2008-08-31 23:59:13 -06:00
|
|
|
/*
|
2008-10-19 10:56:28 -06:00
|
|
|
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
|
2021-01-08 09:04:23 -07:00
|
|
|
Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file)
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2008-10-19 10:56:28 -06:00
|
|
|
Stockfish is free software: you can redistribute it and/or modify
|
2008-08-31 23:59:13 -06:00
|
|
|
it under the terms of the GNU General Public License as published by
|
|
|
|
the Free Software Foundation, either version 3 of the License, or
|
|
|
|
(at your option) any later version.
|
2008-09-03 15:33:49 -06:00
|
|
|
|
2008-10-19 10:56:28 -06:00
|
|
|
Stockfish is distributed in the hope that it will be useful,
|
2008-08-31 23:59:13 -06:00
|
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
|
|
GNU General Public License for more details.
|
2008-09-03 15:33:49 -06:00
|
|
|
|
2008-08-31 23:59:13 -06:00
|
|
|
You should have received a copy of the GNU General Public License
|
|
|
|
along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
*/
|
|
|
|
|
2019-03-31 04:02:19 -06:00
|
|
|
#include <algorithm>
|
2008-08-31 23:59:13 -06:00
|
|
|
#include <cassert>
|
2010-01-19 03:48:22 -07:00
|
|
|
#include <cmath>
|
2014-12-30 02:31:50 -07:00
|
|
|
#include <cstring> // For std::memset
|
2011-12-25 01:04:28 -07:00
|
|
|
#include <iostream>
|
2008-08-31 23:59:13 -06:00
|
|
|
#include <sstream>
|
|
|
|
|
|
|
|
#include "evaluate.h"
|
2014-12-08 00:23:09 -07:00
|
|
|
#include "misc.h"
|
2009-06-11 07:11:08 -06:00
|
|
|
#include "movegen.h"
|
2008-08-31 23:59:13 -06:00
|
|
|
#include "movepick.h"
|
2016-09-17 00:19:06 -06:00
|
|
|
#include "position.h"
|
2008-08-31 23:59:13 -06:00
|
|
|
#include "search.h"
|
|
|
|
#include "thread.h"
|
2018-03-20 18:26:12 -06:00
|
|
|
#include "timeman.h"
|
2008-08-31 23:59:13 -06:00
|
|
|
#include "tt.h"
|
2014-10-26 00:09:19 -06:00
|
|
|
#include "uci.h"
|
2015-01-18 00:05:05 -07:00
|
|
|
#include "syzygy/tbprobe.h"
|
2014-11-25 16:45:28 -07:00
|
|
|
|
2021-02-26 02:02:13 -07:00
|
|
|
namespace Stockfish {
|
|
|
|
|
2011-11-26 04:07:35 -07:00
|
|
|
namespace Search {
|
|
|
|
|
|
|
|
LimitsType Limits;
|
2014-11-30 04:14:14 -07:00
|
|
|
}
|
|
|
|
|
2015-01-18 00:05:05 -07:00
|
|
|
namespace Tablebases {
|
|
|
|
|
|
|
|
int Cardinality;
|
|
|
|
bool RootInTB;
|
|
|
|
bool UseRule50;
|
|
|
|
Depth ProbeDepth;
|
|
|
|
}
|
|
|
|
|
|
|
|
namespace TB = Tablebases;
|
|
|
|
|
2011-12-04 03:46:31 -07:00
|
|
|
using std::string;
|
2012-03-06 02:09:37 -07:00
|
|
|
using Eval::evaluate;
|
2011-12-04 03:46:31 -07:00
|
|
|
using namespace Search;
|
|
|
|
|
2008-08-31 23:59:13 -06:00
|
|
|
namespace {
|
|
|
|
|
2016-01-16 14:34:29 -07:00
|
|
|
// Different node types, used as a template parameter
|
2016-01-18 15:20:16 -07:00
|
|
|
enum NodeType { NonPV, PV };
|
2010-11-08 01:44:28 -07:00
|
|
|
|
2020-04-29 09:39:25 -06:00
|
|
|
constexpr uint64_t TtHitAverageWindow = 4096;
|
|
|
|
constexpr uint64_t TtHitAverageResolution = 1024;
|
Use exploration rate for reductions
This patch measures how frequently search is exploring new configurations.
This is done be computing a running average of ttHit. The ttHitAverage rate
is somewhat low (e.g. 30% for startpos) in the normal case, while it can be
very high if no progress is made (e.g. 90% for the fortress I used for testing).
This information can be used to influence search. In this patch, by adjusting
reductions if the rate > 50%. A first version (using a low ttHitAverageResolution
and this 50% threshold) passed testing:
STC
LLR: 2.96 (-2.94,2.94) [-1.50,4.50]
Total: 26425 W: 5837 L: 5650 D: 14938
http://tests.stockfishchess.org/tests/view/5dcede8b0ebc5902563258fa
LTC
LLR: 2.96 (-2.94,2.94) [0.00,3.50]
Total: 32313 W: 5392 L: 5128 D: 21793
http://tests.stockfishchess.org/tests/view/5dcefb1f0ebc590256325c0e
However, as discussed in pull request 2414, using a larger ttHitAverageResolution
gives a better approximation of the underlying distributions. This needs a slight
adjustment for the threshold as the new distributions are shifted a bit compared
to the older ones, and this threshold seemingly is sensitive (we used 0.53125 here).
https://github.com/official-stockfish/Stockfish/pull/2414
This final version also passed testing, and is used for the patch:
STC
LLR: 2.95 (-2.94,2.94) [-1.50,4.50]
Total: 16025 W: 3555 L: 3399 D: 9071
http://tests.stockfishchess.org/tests/view/5dd070b90ebc5902579e20c2
LTC
LLR: 2.96 (-2.94,2.94) [0.00,3.50]
Total: 37576 W: 6277 L: 5998 D: 25301
http://tests.stockfishchess.org/tests/view/5dd0f58e6f544e798086f224
Closes https://github.com/official-stockfish/Stockfish/pull/2414
Bench: 4989584
2019-11-15 10:16:27 -07:00
|
|
|
|
Remove razoring
has become ineffective now.
STC https://tests.stockfishchess.org/tests/view/5fe653403932f79192d3981a
LLR: 2.95 (-2.94,2.94) {-1.25,0.25}
Total: 63448 W: 5965 L: 5934 D: 51549
Ptnml(0-2): 230, 4738, 21769, 4745, 242
LTC https://tests.stockfishchess.org/tests/view/5fe6f0f03932f79192d39856
LLR: 2.93 (-2.94,2.94) {-0.75,0.25}
Total: 65368 W: 2485 L: 2459 D: 60424
Ptnml(0-2): 33, 2186, 28230, 2192, 43
closes https://github.com/official-stockfish/Stockfish/pull/3278
bench: 4493379
2020-12-26 05:48:04 -07:00
|
|
|
// Futility margin
|
2018-03-07 14:31:51 -07:00
|
|
|
Value futility_margin(Depth d, bool improving) {
|
Tuning Search
This patch tunes constant in search.cpp
STC:
LLR: 2.94 (-2.94,2.94) <-0.50,2.50>
Total: 30648 W: 2580 L: 2410 D: 25658
Ptnml(0-2): 80, 1969, 11093, 2065, 117
https://tests.stockfishchess.org/tests/view/60a71d3cce8ea25a3ef03fae
LTC:
LLR: 2.95 (-2.94,2.94) <0.50,3.50>
Total: 52896 W: 1776 L: 1617 D: 49503
Ptnml(0-2): 13, 1462, 23347, 1605, 21
https://tests.stockfishchess.org/tests/view/60a794ddce8ea25a3ef0400a
closes https://github.com/official-stockfish/Stockfish/pull/3491
Bench: 4004731
2021-05-21 23:47:23 -06:00
|
|
|
return Value(214 * (d - improving));
|
2018-03-07 14:31:51 -07:00
|
|
|
}
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2019-03-05 12:48:29 -07:00
|
|
|
// Reductions lookup table, initialized at startup
|
2019-04-19 09:33:26 -06:00
|
|
|
int Reductions[MAX_MOVES]; // [depth or moveNumber]
|
2010-02-25 09:27:27 -07:00
|
|
|
|
2019-05-07 09:55:56 -06:00
|
|
|
Depth reduction(bool i, Depth d, int mn) {
|
2019-09-28 14:27:23 -06:00
|
|
|
int r = Reductions[d] * Reductions[mn];
|
Tuning Search
This patch tunes constant in search.cpp
STC:
LLR: 2.94 (-2.94,2.94) <-0.50,2.50>
Total: 30648 W: 2580 L: 2410 D: 25658
Ptnml(0-2): 80, 1969, 11093, 2065, 117
https://tests.stockfishchess.org/tests/view/60a71d3cce8ea25a3ef03fae
LTC:
LLR: 2.95 (-2.94,2.94) <0.50,3.50>
Total: 52896 W: 1776 L: 1617 D: 49503
Ptnml(0-2): 13, 1462, 23347, 1605, 21
https://tests.stockfishchess.org/tests/view/60a794ddce8ea25a3ef0400a
closes https://github.com/official-stockfish/Stockfish/pull/3491
Bench: 4004731
2021-05-21 23:47:23 -06:00
|
|
|
return (r + 534) / 1024 + (!i && r > 904);
|
2011-04-24 01:31:47 -06:00
|
|
|
}
|
|
|
|
|
2019-10-18 18:20:38 -06:00
|
|
|
constexpr int futility_move_count(bool improving, Depth depth) {
|
Tuned values for search constants
Tuned search constants after many search patches since the last
successful tune.
1st LTC @ 60+0.6 th 1 :
LLR: 2.97 (-2.94,2.94) {0.25,1.75}
Total: 57656 W: 7369 L: 7036 D: 43251
Ptnml(0-2): 393, 5214, 17336, 5437, 448
https://tests.stockfishchess.org/tests/view/5ee1e074f29b40b0fc95af19
SMP LTC @ 20+0.2 th 8 :
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 83576 W: 9731 L: 9341 D: 64504
Ptnml(0-2): 464, 7062, 26369, 7406, 487
https://tests.stockfishchess.org/tests/view/5ee35a21f29b40b0fc95b008
The changes were rebased on top of a successful patch by Viz (see #2734)
and two different ways of doing this were tested. The successful test
modified the constants in the patch by Viz in a similar manner to the
tuning run:
LTC (rebased) @ 60+0.6 th 1 :
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 193384 W: 24241 L: 23521 D: 145622
Ptnml(0-2): 1309, 17497, 58472, 17993, 1421
https://tests.stockfishchess.org/tests/view/5ee43319ca6c451633a995f9
Further work: the recent patch to quantize eval #2733 affects search quit
quite a bit, so doing another tune in, say, three months time might be a
good idea.
closes https://github.com/official-stockfish/Stockfish/pull/2735
Bench 4246971
2020-06-13 02:54:07 -06:00
|
|
|
return (3 + depth * depth) / (2 - improving);
|
2019-03-05 12:48:29 -07:00
|
|
|
}
|
|
|
|
|
2017-01-25 07:32:10 -07:00
|
|
|
// History and stats update bonus, based on depth
|
2019-09-28 14:27:23 -06:00
|
|
|
int stat_bonus(Depth d) {
|
Tuning Search
This patch tunes constant in search.cpp
STC:
LLR: 2.94 (-2.94,2.94) <-0.50,2.50>
Total: 30648 W: 2580 L: 2410 D: 25658
Ptnml(0-2): 80, 1969, 11093, 2065, 117
https://tests.stockfishchess.org/tests/view/60a71d3cce8ea25a3ef03fae
LTC:
LLR: 2.95 (-2.94,2.94) <0.50,3.50>
Total: 52896 W: 1776 L: 1617 D: 49503
Ptnml(0-2): 13, 1462, 23347, 1605, 21
https://tests.stockfishchess.org/tests/view/60a794ddce8ea25a3ef0400a
closes https://github.com/official-stockfish/Stockfish/pull/3491
Bench: 4004731
2021-05-21 23:47:23 -06:00
|
|
|
return d > 14 ? 73 : 6 * d * d + 229 * d - 215;
|
2017-01-25 07:32:10 -07:00
|
|
|
}
|
|
|
|
|
2021-01-09 08:46:06 -07:00
|
|
|
// Add a small random component to draw evaluations to avoid 3-fold blindness
|
2019-09-27 11:25:22 -06:00
|
|
|
Value value_draw(Thread* thisThread) {
|
|
|
|
return VALUE_DRAW + Value(2 * (thisThread->nodes & 1) - 1);
|
Randomize draw eval
The patch adds a small random component (+-1) to VALUE_DRAW for the evaluation
of draw positions (mostly 3folds). This random component is not static, but
potentially different for each visit of the node (hence derived from the node
counter). The effect is that in positions with many 3fold draw lines, different
lines are followed at each iteration. This keeps the search much more dynamic,
as opposed to being locked to one particular 3fold.
An example of a position where master suffers from 3fold-blindness and this patch
solves quickly is the famous TCEC game 53:
FEN: 3r2k1/pr6/1p3q1p/5R2/3P3p/8/5RP1/3Q2K1 b - - 0 51
master doesn't see that this is a lost position (draw eval up to depth 50) as
Qf6-e6 d4-d5 (found by patch at depth 23) leads to a loss.
The 3fold-blindness is more important at longer TC, the patch was yellow STC and
LTC, but passed VLTC:
STC
LLR: -2.95 (-2.94,2.94) [0.00,5.00]
Total: 46328 W: 10048 L: 9953 D: 26327
http://tests.stockfishchess.org/tests/view/5b9c0ca20ebc592cf275f7c7
LTC
LLR: -2.95 (-2.94,2.94) [0.00,5.00]
Total: 54663 W: 8938 L: 8846 D: 36879
http://tests.stockfishchess.org/tests/view/5b9ca1610ebc592cf27601d3
VLTC
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 31789 W: 4512 L: 4284 D: 22993
http://tests.stockfishchess.org/tests/view/5b9d1a670ebc592cf276076d
Credit to @crossbr for pointing to this problem repeatedly, and giving the hint
that many draw lines are typical in those situations.
Bench: 4756639
2018-10-14 12:33:24 -06:00
|
|
|
}
|
|
|
|
|
2016-01-16 14:34:29 -07:00
|
|
|
// Skill structure is used to implement strength limit
|
2015-01-31 02:43:47 -07:00
|
|
|
struct Skill {
|
2017-10-10 23:49:58 -06:00
|
|
|
explicit Skill(int l) : level(l) {}
|
2015-01-31 02:43:47 -07:00
|
|
|
bool enabled() const { return level < 20; }
|
2019-09-28 14:27:23 -06:00
|
|
|
bool time_to_pick(Depth depth) const { return depth == 1 + level; }
|
2015-01-31 02:43:47 -07:00
|
|
|
Move pick_best(size_t multiPV);
|
2010-02-07 01:53:15 -07:00
|
|
|
|
2015-01-31 02:43:47 -07:00
|
|
|
int level;
|
|
|
|
Move best = MOVE_NONE;
|
|
|
|
};
|
2010-02-07 01:53:15 -07:00
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
template <NodeType NT>
|
2018-05-08 02:43:46 -06:00
|
|
|
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode);
|
2010-05-08 02:54:51 -06:00
|
|
|
|
2018-03-13 01:10:59 -06:00
|
|
|
template <NodeType NT>
|
2019-09-28 14:27:23 -06:00
|
|
|
Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth = 0);
|
2010-10-16 03:01:45 -06:00
|
|
|
|
2010-07-15 03:00:20 -06:00
|
|
|
Value value_to_tt(Value v, int ply);
|
Fix incorrect mate score.
Current master 648c7ec25db2040c0af34dd846dfa3f57af5ad0a will generate an
incorrect mate score for:
```
setoption name Hash value 8
setoption name Threads value 1
position fen 8/1p2KP2/1p4q1/1Pp5/2P5/N1Pp1k2/3P4/1N6 b - - 76 40
go depth 49
```
even though the position is a draw. Generally, SF tries to display only
proven mate scores, so this is a bug.
This was posted http://www.talkchess.com/forum3/viewtopic.php?f=2&t=72166
by Uri Blass, with the correct analysis that this must be related to the
50 moves draw rule being ignored somewhere.
Indeed, this is possible as positions and there eval are stored in the TT,
without reference to the 50mr counter. Depending on the search path followed
a position can thus be mate or draw in the TT (GHI or Graph history interaction).
Therefore, to prove mate lines, the TT content has to be used with care. Rather
than ignoring TT content in general or for mate scores (which impact search or
mate finding), it is possible to be more selective. In particular, @WOnder93
suggested to only ignore the TT if the 50mr draw ply is closer than the mate
ply. This patch implements this idea, by clamping the eval in the TT to
+-VALUE_MATED_IN_MAX_PLY. This retains the TTmove, but causes a research of
these lines (with the current 50mr counter) as needed.
This patch hardly ever affects search (as indicated by the unchanged
bench), but fixes the testcase. As the conditions are very specific,
also mate finding will almost never be less efficient (testing welcome).
It was also shown to pass STC and LTC non-regression testing, in a form
using if/then/else instead of ternary operators:
STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 93605 W: 15346 L: 15340 D: 62919
http://tests.stockfishchess.org/tests/view/5db45bb00ebc5908127538d4
LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 33873 W: 7359 L: 7261 D: 19253
http://tests.stockfishchess.org/tests/view/5db4c8940ebc5902d6b146fc
closes https://github.com/official-stockfish/Stockfish/issues/2370
Bench: 4362323
2019-10-26 08:34:19 -06:00
|
|
|
Value value_from_tt(Value v, int ply, int r50c);
|
2014-11-21 01:10:52 -07:00
|
|
|
void update_pv(Move* pv, Move move, Move* childPv);
|
2017-06-30 09:20:00 -06:00
|
|
|
void update_continuation_histories(Stack* ss, Piece pc, Square to, int bonus);
|
Improve move order near the root
Current move histories are known to work well near the leaves, whilst at
higher depths they aren't very helpful. To address this problem this
patch introduces a table dedicated for what's happening at plies 0-3.
It's structured like mainHistory with ply index instead of color.
It get cleared with each new search and is filled during iterative
deepening at higher depths when recording successful quiet moves near
the root or traversing nodes which were in the principal variation
(ttPv).
Medium TC (20+0.2):
https://tests.stockfishchess.org/tests/view/5e4d358790a0a02810d096dc
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 100910 W: 16682 L: 16376 D: 67852
Ptnml(0-2): 1177, 10983, 25883, 11181, 1231
LTC:
https://tests.stockfishchess.org/tests/view/5e4e2cb790a0a02810d09714
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 80444 W: 10495 L: 10095 D: 59854
Ptnml(0-2): 551, 7479, 23803, 7797, 592
closes https://github.com/official-stockfish/Stockfish/pull/2557
Bench: 4705960
2020-02-21 06:01:59 -07:00
|
|
|
void update_quiet_stats(const Position& pos, Stack* ss, Move move, int bonus, int depth);
|
Refactor final stats updates.
This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done.
Effectively, all stat updates that need to be done after search is finished and a bestmove is found,
are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```.
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```.
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture).
passed non-regression STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 75196 W: 16364 L: 16347 D: 42485
http://tests.stockfishchess.org/tests/view/5db004ec0ebc5902c06db9e1
The diff is most easily readable as ```git diff master --patience```
No functional change
2019-10-23 00:26:47 -06:00
|
|
|
void update_all_stats(const Position& pos, Stack* ss, Move bestMove, Value bestValue, Value beta, Square prevSq,
|
Revert 5 recent patches
Revert 5 patches which were merged, but lead to a regression test that showed negative Elo gain:
http://tests.stockfishchess.org/tests/view/5e307251ab2d69d58394fdb9
This was discussed in depth in:
https://github.com/official-stockfish/Stockfish/issues/2531
Each patch was removed and tested as a simplification, full list below, and the whole combo as well.
After the revert the regression test showed a neutral result:
http://tests.stockfishchess.org/tests/view/5e334851708b13464ceea33c
As a result of this experience, the SPRT testing bounds will be made more strict.
Reverted patches:
1 Dynamic Complexity 6d0eabd5fe2961551477820ab7619e2c31e01ffd :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31fcacec661e2e6a340d08 :
LLR: 2.97 (-2.94,2.94) {-1.50,0.50}
Total: 38130 W: 7326 L: 7189 D: 23615
Ptnml(0-2): 677, 4346, 8843, 4545, 646
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c18fec661e2e6a340d73 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 38675 W: 4941 L: 4866 D: 28868
Ptnml(0-2): 270, 3556, 11429, 3584, 291
3 More bonus for bestMoves on past PV nodes 71e0b5385e2717679a57c6b77d8c7ac5fff3b89f :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31fe93ec661e2e6a340d10 :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 46100 W: 8853 L: 8727 D: 28520
Ptnml(0-2): 796, 5297, 10749, 5387, 813
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c187ec661e2e6a340d71 :
LLR: 2.96 (-2.94,2.94) {-1.50,0.50}
Total: 16920 W: 2161 L: 2055 D: 12704
Ptnml(0-2): 115, 1498, 5006, 1569, 130
4 Tweak Restricted Piece Bonus 0ae00454ba6928d181b46103e5c83e6d58fcebe5 :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31fefaec661e2e6a340d15 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 88328 W: 17060 L: 16997 D: 54271
Ptnml(0-2): 1536, 10446, 20169, 10422, 1581
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c17aec661e2e6a340d6f :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 34784 W: 4551 L: 4466 D: 25767
Ptnml(0-2): 255, 3279, 10061, 3345, 262
5 History update for pruned captures 01b6088af39902001d2d6844561b6a2faa549282 :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31ff5eec661e2e6a340d1a :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 29541 W: 5735 L: 5588 D: 18218
Ptnml(0-2): 483, 3445, 6820, 3469, 545
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c196ec661e2e6a340d75 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 22177 W: 2854 L: 2757 D: 16566
Ptnml(0-2): 143, 2005, 6555, 2055, 164
6 Tweak trapped rook penalty 18fc21eba0368fd5e3c4c4b8ee1000c9ac445425 :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31ffb1ec661e2e6a340d1c :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 24476 W: 4727 L: 4569 D: 15180
Ptnml(0-2): 390, 2834, 5659, 2933, 417
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c19eec661e2e6a340d77 :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 97332 W: 12492 L: 12466 D: 72374
Ptnml(0-2): 690, 9107, 28738, 9034, 720
All 5 as one simplification :
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e334098708b13464ceea330 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 7829 W: 1079 L: 964 D: 5786
Ptnml(0-2): 52, 690, 2281, 781, 65
Bench: 5153165
2020-01-30 13:44:04 -07:00
|
|
|
Move* quietsSearched, int quietCount, Move* capturesSearched, int captureCount, Depth depth);
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2017-08-15 02:05:22 -06:00
|
|
|
// perft() is our utility to verify move generation. All the leaf nodes up
|
|
|
|
// to the given depth are generated and counted, and the sum is returned.
|
|
|
|
template<bool Root>
|
|
|
|
uint64_t perft(Position& pos, Depth depth) {
|
|
|
|
|
|
|
|
StateInfo st;
|
2021-04-19 11:50:19 -06:00
|
|
|
ASSERT_ALIGNED(&st, Eval::NNUE::CacheLineSize);
|
2020-11-03 03:23:35 -07:00
|
|
|
|
2017-08-15 02:05:22 -06:00
|
|
|
uint64_t cnt, nodes = 0;
|
2019-09-28 14:27:23 -06:00
|
|
|
const bool leaf = (depth == 2);
|
2017-08-15 02:05:22 -06:00
|
|
|
|
|
|
|
for (const auto& m : MoveList<LEGAL>(pos))
|
|
|
|
{
|
2019-09-28 14:27:23 -06:00
|
|
|
if (Root && depth <= 1)
|
2017-08-15 02:05:22 -06:00
|
|
|
cnt = 1, nodes++;
|
|
|
|
else
|
|
|
|
{
|
|
|
|
pos.do_move(m, st);
|
2019-09-28 14:27:23 -06:00
|
|
|
cnt = leaf ? MoveList<LEGAL>(pos).size() : perft<false>(pos, depth - 1);
|
2017-08-15 02:05:22 -06:00
|
|
|
nodes += cnt;
|
|
|
|
pos.undo_move(m);
|
|
|
|
}
|
|
|
|
if (Root)
|
|
|
|
sync_cout << UCI::move(m, pos.is_chess960()) << ": " << cnt << sync_endl;
|
|
|
|
}
|
|
|
|
return nodes;
|
|
|
|
}
|
|
|
|
|
2011-01-16 15:40:06 -07:00
|
|
|
} // namespace
|
2008-08-31 23:59:13 -06:00
|
|
|
|
|
|
|
|
2018-02-12 14:57:42 -07:00
|
|
|
/// Search::init() is called at startup to initialize various lookup tables
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2011-11-26 04:07:35 -07:00
|
|
|
void Search::init() {
|
2010-06-01 14:28:45 -06:00
|
|
|
|
2019-04-19 09:33:26 -06:00
|
|
|
for (int i = 1; i < MAX_MOVES; ++i)
|
Simplify the thread term for reduction formula
Dependance on Threads.size() was removed Search::init() for the Reductions[] initialization.
STC:
LLR: 2.94 (-2.94,2.94) <-2.50,0.50>
Total: 17376 W: 1024 L: 929 D: 15423
Ptnml(0-2): 24, 781, 6989, 864, 30
https://tests.stockfishchess.org/tests/view/60ac110812066fd2997957dc
LTC:
LLR: 2.95 (-2.94,2.94) <-2.50,0.50>
Total: 145552 W: 3656 L: 3673 D: 138223
Ptnml(0-2): 37, 3351, 66014, 3340, 34
https://tests.stockfishchess.org/tests/view/60ac267412066fd299795825
closes https://github.com/official-stockfish/Stockfish/pull/3502
Bench 3864295
2021-05-20 12:02:32 -06:00
|
|
|
Reductions[i] = int(21.3 * std::log(i + 0.25 * std::log(i)));
|
2010-06-01 14:28:45 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
|
2017-08-06 05:43:02 -06:00
|
|
|
/// Search::clear() resets search state to its initial value
|
2015-05-06 05:24:00 -06:00
|
|
|
|
2015-10-25 01:30:07 -06:00
|
|
|
void Search::clear() {
|
2015-05-06 05:24:00 -06:00
|
|
|
|
2017-08-06 05:43:02 -06:00
|
|
|
Threads.main()->wait_for_search_finished();
|
|
|
|
|
|
|
|
Time.availableNodes = 0;
|
2015-05-09 03:09:06 -06:00
|
|
|
TT.clear();
|
2017-12-26 02:40:42 -07:00
|
|
|
Threads.clear();
|
2019-03-31 03:47:36 -06:00
|
|
|
Tablebases::init(Options["SyzygyPath"]); // Free mapped files
|
2015-05-06 05:24:00 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
|
2019-03-31 03:47:36 -06:00
|
|
|
/// MainThread::search() is started when the program receives the UCI 'go'
|
|
|
|
/// command. It searches from the root position and outputs the "bestmove".
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2015-11-05 00:40:23 -07:00
|
|
|
void MainThread::search() {
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2017-08-15 02:05:22 -06:00
|
|
|
if (Limits.perft)
|
|
|
|
{
|
2019-09-28 14:27:23 -06:00
|
|
|
nodes = perft<true>(rootPos, Limits.perft);
|
2017-08-15 02:05:22 -06:00
|
|
|
sync_cout << "\nNodes searched: " << nodes << "\n" << sync_endl;
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
Color us = rootPos.side_to_move();
|
|
|
|
Time.init(Limits, us, rootPos.game_ply());
|
2017-06-06 01:48:57 -06:00
|
|
|
TT.new_search();
|
2011-11-06 05:13:54 -07:00
|
|
|
|
2020-09-09 02:49:31 -06:00
|
|
|
Eval::NNUE::verify();
|
Add NNUE evaluation
This patch ports the efficiently updatable neural network (NNUE) evaluation to Stockfish.
Both the NNUE and the classical evaluations are available, and can be used to
assign a value to a position that is later used in alpha-beta (PVS) search to find the
best move. The classical evaluation computes this value as a function of various chess
concepts, handcrafted by experts, tested and tuned using fishtest. The NNUE evaluation
computes this value with a neural network based on basic inputs. The network is optimized
and trained on the evalutions of millions of positions at moderate search depth.
The NNUE evaluation was first introduced in shogi, and ported to Stockfish afterward.
It can be evaluated efficiently on CPUs, and exploits the fact that only parts
of the neural network need to be updated after a typical chess move.
[The nodchip repository](https://github.com/nodchip/Stockfish) provides additional
tools to train and develop the NNUE networks.
This patch is the result of contributions of various authors, from various communities,
including: nodchip, ynasu87, yaneurao (initial port and NNUE authors), domschl, FireFather,
rqs, xXH4CKST3RXx, tttak, zz4032, joergoster, mstembera, nguyenpham, erbsenzaehler,
dorzechowski, and vondele.
This new evaluation needed various changes to fishtest and the corresponding infrastructure,
for which tomtor, ppigazzini, noobpwnftw, daylen, and vondele are gratefully acknowledged.
The first networks have been provided by gekkehenker and sergiovieri, with the latter
net (nn-97f742aaefcd.nnue) being the current default.
The evaluation function can be selected at run time with the `Use NNUE` (true/false) UCI option,
provided the `EvalFile` option points the the network file (depending on the GUI, with full path).
The performance of the NNUE evaluation relative to the classical evaluation depends somewhat on
the hardware, and is expected to improve quickly, but is currently on > 80 Elo on fishtest:
60000 @ 10+0.1 th 1
https://tests.stockfishchess.org/tests/view/5f28fe6ea5abc164f05e4c4c
ELO: 92.77 +-2.1 (95%) LOS: 100.0%
Total: 60000 W: 24193 L: 8543 D: 27264
Ptnml(0-2): 609, 3850, 9708, 10948, 4885
40000 @ 20+0.2 th 8
https://tests.stockfishchess.org/tests/view/5f290229a5abc164f05e4c58
ELO: 89.47 +-2.0 (95%) LOS: 100.0%
Total: 40000 W: 12756 L: 2677 D: 24567
Ptnml(0-2): 74, 1583, 8550, 7776, 2017
At the same time, the impact on the classical evaluation remains minimal, causing no significant
regression:
sprt @ 10+0.1 th 1
https://tests.stockfishchess.org/tests/view/5f2906a2a5abc164f05e4c5b
LLR: 2.94 (-2.94,2.94) {-6.00,-4.00}
Total: 34936 W: 6502 L: 6825 D: 21609
Ptnml(0-2): 571, 4082, 8434, 3861, 520
sprt @ 60+0.6 th 1
https://tests.stockfishchess.org/tests/view/5f2906cfa5abc164f05e4c5d
LLR: 2.93 (-2.94,2.94) {-6.00,-4.00}
Total: 10088 W: 1232 L: 1265 D: 7591
Ptnml(0-2): 49, 914, 3170, 843, 68
The needed networks can be found at https://tests.stockfishchess.org/nns
It is recommended to use the default one as indicated by the `EvalFile` UCI option.
Guidelines for testing new nets can be found at
https://github.com/glinscott/fishtest/wiki/Creating-my-first-test#nnue-net-tests
Integration has been discussed in various issues:
https://github.com/official-stockfish/Stockfish/issues/2823
https://github.com/official-stockfish/Stockfish/issues/2728
The integration branch will be closed after the merge:
https://github.com/official-stockfish/Stockfish/pull/2825
https://github.com/official-stockfish/Stockfish/tree/nnue-player-wip
closes https://github.com/official-stockfish/Stockfish/pull/2912
This will be an exciting time for computer chess, looking forward to seeing the evolution of
this approach.
Bench: 4746616
2020-08-05 09:11:15 -06:00
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
if (rootMoves.empty())
|
2008-10-30 04:35:44 -06:00
|
|
|
{
|
2017-08-13 06:33:25 -06:00
|
|
|
rootMoves.emplace_back(MOVE_NONE);
|
2012-08-29 05:28:59 -06:00
|
|
|
sync_cout << "info depth 0 score "
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
<< UCI::value(rootPos.checkers() ? -VALUE_MATE : VALUE_DRAW)
|
2012-10-24 06:37:52 -06:00
|
|
|
<< sync_endl;
|
2012-01-14 03:45:54 -07:00
|
|
|
}
|
2014-11-10 06:46:05 -07:00
|
|
|
else
|
|
|
|
{
|
2020-05-31 23:31:14 -06:00
|
|
|
Threads.start_searching(); // start non-main threads
|
|
|
|
Thread::search(); // main thread start searching
|
2014-11-10 06:46:05 -07:00
|
|
|
}
|
2013-05-03 02:25:25 -06:00
|
|
|
|
2013-12-02 11:04:09 -07:00
|
|
|
// When we reach the maximum depth, we can arrive here without a raise of
|
2017-07-13 17:07:19 -06:00
|
|
|
// Threads.stop. However, if we are pondering or in an infinite search,
|
2013-12-02 11:04:09 -07:00
|
|
|
// the UCI protocol states that we shouldn't print the best move before the
|
|
|
|
// GUI sends a "stop" or "ponderhit" command. We therefore simply wait here
|
Simplify pondering time management (#1899)
stopOnPonderhit is used to stop search quickly on a ponderhit. It is set by mainThread as part of its time management. However, master employs it as a signal between mainThread and the UCI thread. This is not necessary, it is sufficient for the UCI thread to signal that pondering finished, and mainThread should do its usual time-keeping job, and in this case stop immediately.
This patch implements this, removing stopOnPonderHit as an atomic variable from the ThreadPool,
and moving it as a normal variable to mainThread, reducing its scope. In MainThread::check_time() the search is stopped immediately if ponder switches to false, and the variable stopOnPonderHit is set.
Furthermore, ponder has been moved to mainThread, as the variable is only used to exchange signals between the UCI thread and mainThread.
The version has been tested locally (as fishtest doesn't support ponder):
Score of ponderSimp vs master: 2616 - 2528 - 8630 [0.503] 13774
Elo difference: 2.22 +/- 3.54
which indicates no regression.
No functional change.
2019-01-20 11:14:24 -07:00
|
|
|
// until the GUI sends one of those commands.
|
2017-08-04 11:48:07 -06:00
|
|
|
|
Simplify pondering time management (#1899)
stopOnPonderhit is used to stop search quickly on a ponderhit. It is set by mainThread as part of its time management. However, master employs it as a signal between mainThread and the UCI thread. This is not necessary, it is sufficient for the UCI thread to signal that pondering finished, and mainThread should do its usual time-keeping job, and in this case stop immediately.
This patch implements this, removing stopOnPonderHit as an atomic variable from the ThreadPool,
and moving it as a normal variable to mainThread, reducing its scope. In MainThread::check_time() the search is stopped immediately if ponder switches to false, and the variable stopOnPonderHit is set.
Furthermore, ponder has been moved to mainThread, as the variable is only used to exchange signals between the UCI thread and mainThread.
The version has been tested locally (as fishtest doesn't support ponder):
Score of ponderSimp vs master: 2616 - 2528 - 8630 [0.503] 13774
Elo difference: 2.22 +/- 3.54
which indicates no regression.
No functional change.
2019-01-20 11:14:24 -07:00
|
|
|
while (!Threads.stop && (ponder || Limits.infinite))
|
2017-08-04 11:48:07 -06:00
|
|
|
{} // Busy wait for a stop or a ponder reset
|
2010-12-30 08:18:22 -07:00
|
|
|
|
2017-08-04 11:48:07 -06:00
|
|
|
// Stop the threads if not already stopped (also raise the stop if
|
|
|
|
// "ponderhit" just reset Threads.ponder).
|
2017-07-13 17:07:19 -06:00
|
|
|
Threads.stop = true;
|
2015-11-09 01:50:02 -07:00
|
|
|
|
|
|
|
// Wait until all threads have finished
|
2020-05-31 23:31:14 -06:00
|
|
|
Threads.wait_for_search_finished();
|
2015-11-09 01:50:02 -07:00
|
|
|
|
2017-09-29 08:39:12 -06:00
|
|
|
// When playing in 'nodes as time' mode, subtract the searched nodes from
|
|
|
|
// the available ones before exiting.
|
|
|
|
if (Limits.npmsec)
|
|
|
|
Time.availableNodes += Limits.inc[us] - Threads.nodes_searched();
|
|
|
|
|
2015-11-02 02:58:18 -07:00
|
|
|
Thread* bestThread = this;
|
2019-03-31 03:47:36 -06:00
|
|
|
|
2020-07-09 14:01:06 -06:00
|
|
|
if ( int(Options["MultiPV"]) == 1
|
|
|
|
&& !Limits.depth
|
|
|
|
&& !(Skill(Options["Skill Level"]).enabled() || int(Options["UCI_LimitStrength"]))
|
|
|
|
&& rootMoves[0].pv[0] != MOVE_NONE)
|
2020-05-31 23:31:14 -06:00
|
|
|
bestThread = Threads.get_best_thread();
|
2015-11-02 02:58:18 -07:00
|
|
|
|
2020-04-12 12:30:08 -06:00
|
|
|
bestPreviousScore = bestThread->rootMoves[0].score;
|
2016-01-03 07:00:56 -07:00
|
|
|
|
2018-02-12 14:57:42 -07:00
|
|
|
// Send again PV info if we have a new best thread
|
2015-11-02 02:58:18 -07:00
|
|
|
if (bestThread != this)
|
|
|
|
sync_cout << UCI::pv(bestThread->rootPos, bestThread->completedDepth, -VALUE_INFINITE, VALUE_INFINITE) << sync_endl;
|
2014-11-23 17:53:00 -07:00
|
|
|
|
2015-11-02 02:58:18 -07:00
|
|
|
sync_cout << "bestmove " << UCI::move(bestThread->rootMoves[0].pv[0], rootPos.is_chess960());
|
|
|
|
|
|
|
|
if (bestThread->rootMoves[0].pv.size() > 1 || bestThread->rootMoves[0].extract_ponder_from_tt(rootPos))
|
|
|
|
std::cout << " ponder " << UCI::move(bestThread->rootMoves[0].pv[1], rootPos.is_chess960());
|
2014-11-23 17:53:00 -07:00
|
|
|
|
|
|
|
std::cout << sync_endl;
|
2008-08-31 23:59:13 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
|
2017-03-14 22:00:03 -06:00
|
|
|
/// Thread::search() is the main iterative deepening loop. It calls search()
|
|
|
|
/// repeatedly with increasing depth until the allocated thinking time has been
|
|
|
|
/// consumed, the user stops the search, or the maximum search depth is reached.
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2015-11-05 00:40:23 -07:00
|
|
|
void Thread::search() {
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2019-03-31 03:47:36 -06:00
|
|
|
// To allow access to (ss-7) up to (ss+2), the stack must be oversized.
|
2018-12-19 13:04:36 -07:00
|
|
|
// The former is needed to allow update_continuation_histories(ss-1, ...),
|
2019-03-31 03:47:36 -06:00
|
|
|
// which accesses its argument at ss-6, also near the root.
|
2018-12-19 13:04:36 -07:00
|
|
|
// The latter is needed for statScores and killer initialization.
|
2019-02-27 13:25:12 -07:00
|
|
|
Stack stack[MAX_PLY+10], *ss = stack+7;
|
Fix a segfault.
this patch fixes a rare but reproducible segfault observed playing a
multi-threaded match, it is discussed somewhat in fishcooking.
From the core file, it could be observed that the issue was in qsearch, namely:
````
ss->pv[0] = MOVE_NONE;
````
and the backtrace shows the it arrives there via razoring, called from the rootNode:
````
(gdb) bt
alpha=-19, beta=682, depth=DEPTH_ZERO) at search.cpp:1247
````
Indeed, ss->pv can indeed by a nullptr at the rootNode. However, why is the
segfault so rare ?
The reason is that the condition that guards razoring:
````
(depth < 2 * ONE_PLY && eval <= alpha - RazorMargin)
````
is almost never true, since at the root alpha for depth < 5 is -VALUE_INFINITE.
Nevertheless with the new failHigh scheme, this is not guaranteed, and rootDepth > 5,
can still result in a depth < 2 search at the rootNode. If now another thread,
via the hash, writes a new low eval to the rootPos qsearch can be entered.
Rare but not unseen... I assume that some of the crashes in fishtest recently
might be due to this.
Closes https://github.com/official-stockfish/Stockfish/pull/1860
No functional change
2018-12-16 01:51:29 -07:00
|
|
|
Move pv[MAX_PLY+1];
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
Value bestValue, alpha, beta, delta;
|
Replace easyMove with simple scheme
Reduces time for a stable bestMove, giving some of the won time for the next move.
the version before the pvDraw passed both STC and LTC
passed STC:
http://tests.stockfishchess.org/tests/view/59e98d5a0ebc590ccbb896ec
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 78561 W: 13945 L: 13921 D: 50695
elo = 0.106 +- 1.445 LOS: 55.716%
passed LTC:
http://tests.stockfishchess.org/tests/view/59eb9df90ebc590ccbb897ae
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 29056 W: 3640 L: 3530 D: 21886
elo = 1.315 +- 1.982 LOS: 90.314%
This version, rebased on pvDrawPR with the obvious change, was verified again on STC:
http://tests.stockfishchess.org/tests/view/59ee104e0ebc590ccbb89899
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 19890 W: 3648 L: 3525 D: 12717
elo = 2.149 +- 2.895 LOS: 92.692%
and LTC:
http://tests.stockfishchess.org/tests/view/59f9673a0ebc590ccbb89ea0
Total : 17966
Win : 2273 ( 12.652%)
Loss : 2149 ( 11.961%)
Draw : 13544 ( 75.387%)
Score : 50.345%
Sensitivity : 0.014%
2*(W-L)/(W+L) : 5.608%
LLR [-3.0, 1.0] : 2.95
BayesElo range : [ -1.161, 4.876, 10.830] (DrawElo: 341.132)
LogisticElo range : [ -0.501, 2.105, 4.677]
LOS : 94.369 %
LTC again:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 17966 W: 2273 L: 2149 D: 13544
LogisticElo range : [ -0.501, 2.105, 4.677]
LOS : 94.369 %
unchanged bench: 5234652
2017-11-03 06:51:53 -06:00
|
|
|
Move lastBestMove = MOVE_NONE;
|
2019-09-28 14:27:23 -06:00
|
|
|
Depth lastBestMoveDepth = 0;
|
2015-12-23 02:07:54 -07:00
|
|
|
MainThread* mainThread = (this == Threads.main() ? Threads.main() : nullptr);
|
Use average bestMoveChanges across all threads #2072
The current update only by main thread depends on the luck of
whether main thread sees any/many changes to the best move or not.
It then makes large, lumpy changes to the time to be
used (1x, 2x, 3x, etc) depending on that sample of 1.
Use the average across all threads to get a more reliable
number with a smoother distribution.
STC @ 5+0.05 th 4 :
LLR: 2.95 (-2.94,2.94) [0.50,4.50]
Total: 51899 W: 11446 L: 11029 D: 29424
http://tests.stockfishchess.org/tests/view/5ca32ff20ebc5925cf0016fb
STC @ 5+0.05 th 8 :
LLR: 2.96 (-2.94,2.94) [0.50,4.50]
Total: 13851 W: 2843 L: 2620 D: 8388
http://tests.stockfishchess.org/tests/view/5ca35ae00ebc5925cf001adb
LTC @ 20+0.2 th 8 :
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 48527 W: 7941 L: 7635 D: 32951
http://tests.stockfishchess.org/tests/view/5ca37cb70ebc5925cf001cec
Further work:
Similar changes might be possible for the fallingEval and timeReduction calculations (and elsewhere?), using either the min, average or max values across all threads.
Bench 3506898
2019-04-03 01:35:55 -06:00
|
|
|
double timeReduction = 1, totBestMoveChanges = 0;
|
Introduce dynamic contempt
Make contempt dependent on the current score of the root position.
The idea is that we now use a linear formula like the following to decide
on the contempt to use during a search :
contempt = x + y * eval
where x is the base contempt set by the user in the "Contempt" UCI option,
and y * eval is the dynamic part which adapts itself to the estimation of
the evaluation of the root position returned by the search. In this patch,
we use x = 18 centipawns by default, and the y * eval correction can go
from -20 centipawns if the root eval is less than -2.0 pawns, up to +20
centipawns when the root eval is more than 2.0 pawns.
To summarize, the new contempt goes from -0.02 to 0.38 pawns, depending if
Stockfish is losing or winning, with an average value of 0.18 pawns by default.
STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 110052 W: 24614 L: 23938 D: 61500
http://tests.stockfishchess.org/tests/view/5a72e6020ebc590f2c86ea20
LTC:
LLR: 2.97 (-2.94,2.94) [0.00,5.00]
Total: 16470 W: 2896 L: 2705 D: 10869
http://tests.stockfishchess.org/tests/view/5a76c5b90ebc5902971a9830
A second match at LTC was organised against the current master:
ELO: 1.45 +-2.9 (95%) LOS: 84.0%
Total: 19369 W: 3350 L: 3269 D: 12750
http://tests.stockfishchess.org/tests/view/5a7acf980ebc5902971a9a2e
Finally, we checked that there is no apparent problem with multithreading,
despite the fact that some threads might have a slightly different contempt
level that the main thread.
Match of this version against master, both using 5 threads, time control 30+0.3:
ELO: 2.18 +-3.2 (95%) LOS: 90.8%
Total: 14840 W: 2502 L: 2409 D: 9929
http://tests.stockfishchess.org/tests/view/5a7bf3e80ebc5902971a9aa2
Include suggestions from Marco Costalba, Aram Tumanian, Ronald de Man, etc.
Bench: 5207156
2018-02-09 10:43:53 -07:00
|
|
|
Color us = rootPos.side_to_move();
|
2019-12-08 04:06:19 -07:00
|
|
|
int iterIdx = 0;
|
2008-10-30 04:35:44 -06:00
|
|
|
|
2019-02-27 13:25:12 -07:00
|
|
|
std::memset(ss-7, 0, 10 * sizeof(Stack));
|
|
|
|
for (int i = 7; i > 0; i--)
|
2019-10-08 08:44:01 -06:00
|
|
|
(ss-i)->continuationHistory = &this->continuationHistory[0][0][NO_PIECE][0]; // Use as a sentinel
|
2019-10-05 08:42:36 -06:00
|
|
|
|
Fix a segfault.
this patch fixes a rare but reproducible segfault observed playing a
multi-threaded match, it is discussed somewhat in fishcooking.
From the core file, it could be observed that the issue was in qsearch, namely:
````
ss->pv[0] = MOVE_NONE;
````
and the backtrace shows the it arrives there via razoring, called from the rootNode:
````
(gdb) bt
alpha=-19, beta=682, depth=DEPTH_ZERO) at search.cpp:1247
````
Indeed, ss->pv can indeed by a nullptr at the rootNode. However, why is the
segfault so rare ?
The reason is that the condition that guards razoring:
````
(depth < 2 * ONE_PLY && eval <= alpha - RazorMargin)
````
is almost never true, since at the root alpha for depth < 5 is -VALUE_INFINITE.
Nevertheless with the new failHigh scheme, this is not guaranteed, and rootDepth > 5,
can still result in a depth < 2 search at the rootNode. If now another thread,
via the hash, writes a new low eval to the rootPos qsearch can be entered.
Rare but not unseen... I assume that some of the crashes in fishtest recently
might be due to this.
Closes https://github.com/official-stockfish/Stockfish/pull/1860
No functional change
2018-12-16 01:51:29 -07:00
|
|
|
ss->pv = pv;
|
2011-01-17 02:44:00 -07:00
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
bestValue = delta = alpha = -VALUE_INFINITE;
|
|
|
|
beta = VALUE_INFINITE;
|
2015-03-12 13:49:30 -06:00
|
|
|
|
2019-12-08 04:06:19 -07:00
|
|
|
if (mainThread)
|
|
|
|
{
|
2020-04-12 12:30:08 -06:00
|
|
|
if (mainThread->bestPreviousScore == VALUE_INFINITE)
|
2020-05-23 05:26:13 -06:00
|
|
|
for (int i = 0; i < 4; ++i)
|
2019-12-08 04:06:19 -07:00
|
|
|
mainThread->iterValue[i] = VALUE_ZERO;
|
|
|
|
else
|
2020-05-23 05:26:13 -06:00
|
|
|
for (int i = 0; i < 4; ++i)
|
2020-04-12 12:30:08 -06:00
|
|
|
mainThread->iterValue[i] = mainThread->bestPreviousScore;
|
2019-12-08 04:06:19 -07:00
|
|
|
}
|
|
|
|
|
Keep low ply history from previous move
This patch keeps the low-ply history from the previous move, shifting the data down by 2 ply.
Tested with closedpos book:
STC:
LLR: 2.93 (-2.94,2.94) {-0.50,1.50}
Total: 71584 W: 14175 L: 13891 D: 43518
Ptnml(0-2): 1069, 8228, 16993, 8354, 1148
https://tests.stockfishchess.org/tests/view/5ec0eaafe9d85f94dc429974
LTC:
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 96552 W: 13946 L: 13498 D: 69108
Ptnml(0-2): 676, 9082, 28375, 9404, 739
https://tests.stockfishchess.org/tests/view/5ec145efe9d85f94dc4299b0
closes https://github.com/official-stockfish/Stockfish/pull/2688
Bench 5148950
2020-05-21 14:17:21 -06:00
|
|
|
std::copy(&lowPlyHistory[2][0], &lowPlyHistory.back().back() + 1, &lowPlyHistory[0][0]);
|
|
|
|
std::fill(&lowPlyHistory[MAX_LPH - 2][0], &lowPlyHistory.back().back() + 1, 0);
|
|
|
|
|
2020-05-23 05:26:13 -06:00
|
|
|
size_t multiPV = size_t(Options["MultiPV"]);
|
UCI_Elo implementation (#2225)
This exploits the recent fractional Skill Level, and is a result from some discussion in #2221 and the older #758.
Basically, if UCI_LimitStrength is set, it will internally convert UCI_Elo to a matching fractional Skill Level.
The Elo estimate is based on games at TC 60+0.6, Hash 64Mb, 8moves_v3.pgn, rated with Ordo, anchored to goldfish1.13 (CCRL 40/4 ~2000).
Note that this is mostly about internal consistency, the anchoring to CCRL is a bit weak, e.g. within this tournament,
goldfish and sungorus only have a 200Elo difference, their rating difference on CCRL is 300Elo.
I propose that we continue to expose 'Skill Level' as an UCI option, for backwards compatibility.
The result of a tournament under those conditions are given by the following table, where the player name reflects the UCI_Elo.
# PLAYER : RATING ERROR POINTS PLAYED (%) CFS(%)
1 Elo2837 : 2792.2 50.8 536.5 711 75 100
2 Elo2745 : 2739.0 49.0 487.5 711 69 100
3 Elo2654 : 2666.4 49.2 418.0 711 59 100
4 Elo2562 : 2604.5 38.5 894.5 1383 65 100
5 Elo2471 : 2515.2 38.1 651.5 924 71 100
6 Elo2380 : 2365.9 35.4 478.5 924 52 100
7 Elo2289 : 2290.0 28.0 864.0 1596 54 100
8 sungorus1.4 : 2204.9 27.8 680.5 1596 43 60
9 Elo2197 : 2201.1 30.1 523.5 924 57 100
10 Elo2106 : 2103.8 24.5 730.5 1428 51 100
11 Elo2014 : 2030.5 30.3 377.5 756 50 98
12 goldfish1.13 : 2000.0 ---- 511.0 1428 36 100
13 Elo1923 : 1928.5 30.9 641.5 1260 51 100
14 Elo1831 : 1829.0 42.1 370.5 756 49 100
15 Elo1740 : 1738.3 42.9 277.5 756 37 100
16 Elo1649 : 1625.0 42.1 525.5 1260 42 100
17 Elo1558 : 1521.5 49.9 298.0 756 39 100
18 Elo1467 : 1471.3 51.3 246.5 756 33 100
19 Elo1375 : 1407.1 51.9 183.0 756 24 ---
It can be observed that all set Elos correspond within the error bars with the observed Ordo rating.
No functional change
2019-07-14 06:47:50 -06:00
|
|
|
|
2019-07-01 06:07:54 -06:00
|
|
|
// Pick integer skill levels, but non-deterministically round up or down
|
|
|
|
// such that the average integer skill corresponds to the input floating point one.
|
UCI_Elo implementation (#2225)
This exploits the recent fractional Skill Level, and is a result from some discussion in #2221 and the older #758.
Basically, if UCI_LimitStrength is set, it will internally convert UCI_Elo to a matching fractional Skill Level.
The Elo estimate is based on games at TC 60+0.6, Hash 64Mb, 8moves_v3.pgn, rated with Ordo, anchored to goldfish1.13 (CCRL 40/4 ~2000).
Note that this is mostly about internal consistency, the anchoring to CCRL is a bit weak, e.g. within this tournament,
goldfish and sungorus only have a 200Elo difference, their rating difference on CCRL is 300Elo.
I propose that we continue to expose 'Skill Level' as an UCI option, for backwards compatibility.
The result of a tournament under those conditions are given by the following table, where the player name reflects the UCI_Elo.
# PLAYER : RATING ERROR POINTS PLAYED (%) CFS(%)
1 Elo2837 : 2792.2 50.8 536.5 711 75 100
2 Elo2745 : 2739.0 49.0 487.5 711 69 100
3 Elo2654 : 2666.4 49.2 418.0 711 59 100
4 Elo2562 : 2604.5 38.5 894.5 1383 65 100
5 Elo2471 : 2515.2 38.1 651.5 924 71 100
6 Elo2380 : 2365.9 35.4 478.5 924 52 100
7 Elo2289 : 2290.0 28.0 864.0 1596 54 100
8 sungorus1.4 : 2204.9 27.8 680.5 1596 43 60
9 Elo2197 : 2201.1 30.1 523.5 924 57 100
10 Elo2106 : 2103.8 24.5 730.5 1428 51 100
11 Elo2014 : 2030.5 30.3 377.5 756 50 98
12 goldfish1.13 : 2000.0 ---- 511.0 1428 36 100
13 Elo1923 : 1928.5 30.9 641.5 1260 51 100
14 Elo1831 : 1829.0 42.1 370.5 756 49 100
15 Elo1740 : 1738.3 42.9 277.5 756 37 100
16 Elo1649 : 1625.0 42.1 525.5 1260 42 100
17 Elo1558 : 1521.5 49.9 298.0 756 39 100
18 Elo1467 : 1471.3 51.3 246.5 756 33 100
19 Elo1375 : 1407.1 51.9 183.0 756 24 ---
It can be observed that all set Elos correspond within the error bars with the observed Ordo rating.
No functional change
2019-07-14 06:47:50 -06:00
|
|
|
// UCI_Elo is converted to a suitable fractional skill level, using anchoring
|
|
|
|
// to CCRL Elo (goldfish 1.13 = 2000) and a fit through Ordo derived Elo
|
|
|
|
// for match (TC 60+0.6) results spanning a wide range of k values.
|
2019-07-01 06:07:54 -06:00
|
|
|
PRNG rng(now());
|
UCI_Elo implementation (#2225)
This exploits the recent fractional Skill Level, and is a result from some discussion in #2221 and the older #758.
Basically, if UCI_LimitStrength is set, it will internally convert UCI_Elo to a matching fractional Skill Level.
The Elo estimate is based on games at TC 60+0.6, Hash 64Mb, 8moves_v3.pgn, rated with Ordo, anchored to goldfish1.13 (CCRL 40/4 ~2000).
Note that this is mostly about internal consistency, the anchoring to CCRL is a bit weak, e.g. within this tournament,
goldfish and sungorus only have a 200Elo difference, their rating difference on CCRL is 300Elo.
I propose that we continue to expose 'Skill Level' as an UCI option, for backwards compatibility.
The result of a tournament under those conditions are given by the following table, where the player name reflects the UCI_Elo.
# PLAYER : RATING ERROR POINTS PLAYED (%) CFS(%)
1 Elo2837 : 2792.2 50.8 536.5 711 75 100
2 Elo2745 : 2739.0 49.0 487.5 711 69 100
3 Elo2654 : 2666.4 49.2 418.0 711 59 100
4 Elo2562 : 2604.5 38.5 894.5 1383 65 100
5 Elo2471 : 2515.2 38.1 651.5 924 71 100
6 Elo2380 : 2365.9 35.4 478.5 924 52 100
7 Elo2289 : 2290.0 28.0 864.0 1596 54 100
8 sungorus1.4 : 2204.9 27.8 680.5 1596 43 60
9 Elo2197 : 2201.1 30.1 523.5 924 57 100
10 Elo2106 : 2103.8 24.5 730.5 1428 51 100
11 Elo2014 : 2030.5 30.3 377.5 756 50 98
12 goldfish1.13 : 2000.0 ---- 511.0 1428 36 100
13 Elo1923 : 1928.5 30.9 641.5 1260 51 100
14 Elo1831 : 1829.0 42.1 370.5 756 49 100
15 Elo1740 : 1738.3 42.9 277.5 756 37 100
16 Elo1649 : 1625.0 42.1 525.5 1260 42 100
17 Elo1558 : 1521.5 49.9 298.0 756 39 100
18 Elo1467 : 1471.3 51.3 246.5 756 33 100
19 Elo1375 : 1407.1 51.9 183.0 756 24 ---
It can be observed that all set Elos correspond within the error bars with the observed Ordo rating.
No functional change
2019-07-14 06:47:50 -06:00
|
|
|
double floatLevel = Options["UCI_LimitStrength"] ?
|
2020-07-11 08:59:33 -06:00
|
|
|
std::clamp(std::pow((Options["UCI_Elo"] - 1346.6) / 143.4, 1 / 0.806), 0.0, 20.0) :
|
UCI_Elo implementation (#2225)
This exploits the recent fractional Skill Level, and is a result from some discussion in #2221 and the older #758.
Basically, if UCI_LimitStrength is set, it will internally convert UCI_Elo to a matching fractional Skill Level.
The Elo estimate is based on games at TC 60+0.6, Hash 64Mb, 8moves_v3.pgn, rated with Ordo, anchored to goldfish1.13 (CCRL 40/4 ~2000).
Note that this is mostly about internal consistency, the anchoring to CCRL is a bit weak, e.g. within this tournament,
goldfish and sungorus only have a 200Elo difference, their rating difference on CCRL is 300Elo.
I propose that we continue to expose 'Skill Level' as an UCI option, for backwards compatibility.
The result of a tournament under those conditions are given by the following table, where the player name reflects the UCI_Elo.
# PLAYER : RATING ERROR POINTS PLAYED (%) CFS(%)
1 Elo2837 : 2792.2 50.8 536.5 711 75 100
2 Elo2745 : 2739.0 49.0 487.5 711 69 100
3 Elo2654 : 2666.4 49.2 418.0 711 59 100
4 Elo2562 : 2604.5 38.5 894.5 1383 65 100
5 Elo2471 : 2515.2 38.1 651.5 924 71 100
6 Elo2380 : 2365.9 35.4 478.5 924 52 100
7 Elo2289 : 2290.0 28.0 864.0 1596 54 100
8 sungorus1.4 : 2204.9 27.8 680.5 1596 43 60
9 Elo2197 : 2201.1 30.1 523.5 924 57 100
10 Elo2106 : 2103.8 24.5 730.5 1428 51 100
11 Elo2014 : 2030.5 30.3 377.5 756 50 98
12 goldfish1.13 : 2000.0 ---- 511.0 1428 36 100
13 Elo1923 : 1928.5 30.9 641.5 1260 51 100
14 Elo1831 : 1829.0 42.1 370.5 756 49 100
15 Elo1740 : 1738.3 42.9 277.5 756 37 100
16 Elo1649 : 1625.0 42.1 525.5 1260 42 100
17 Elo1558 : 1521.5 49.9 298.0 756 39 100
18 Elo1467 : 1471.3 51.3 246.5 756 33 100
19 Elo1375 : 1407.1 51.9 183.0 756 24 ---
It can be observed that all set Elos correspond within the error bars with the observed Ordo rating.
No functional change
2019-07-14 06:47:50 -06:00
|
|
|
double(Options["Skill Level"]);
|
|
|
|
int intLevel = int(floatLevel) +
|
|
|
|
((floatLevel - int(floatLevel)) * 1024 > rng.rand<unsigned>() % 1024 ? 1 : 0);
|
2019-07-01 06:07:54 -06:00
|
|
|
Skill skill(intLevel);
|
2013-07-03 10:58:49 -06:00
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
// When playing with strength handicap enable MultiPV search that we will
|
|
|
|
// use behind the scenes to retrieve a set of possible moves.
|
|
|
|
if (skill.enabled())
|
|
|
|
multiPV = std::max(multiPV, (size_t)4);
|
2015-03-29 01:24:17 -06:00
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
multiPV = std::min(multiPV, rootMoves.size());
|
2020-04-29 09:39:25 -06:00
|
|
|
ttHitAverage = TtHitAverageWindow * TtHitAverageResolution / 2;
|
2012-10-24 04:05:20 -06:00
|
|
|
|
2018-04-18 20:16:19 -06:00
|
|
|
int ct = int(Options["Contempt"]) * PawnValueEg / 100; // From centipawns
|
Analysis Contempt combo box
This patch introduces an Analysis Contempt UCI combo box to control
the behaviour of contempt during analysis. The possible values are
Both, Off, White, Black. Technically, the engine is supposed to be in
analysis mode if UCI_AnalyseMode is set by the graphical user interface
or if the user has chosen infinite analysis mode ("go infinite").
Credits: the idea for the combo box is due to Michel Van den Bergh.
No functional change (outside analysis mode).
-----------------------------------------------------
The so-called "contempt" is an optimism value that the engine adds
to one color to avoid simplifications and keep tension in the position
during its search. It was introduced in Stockfish 9 and seemed to give
good results during the TCEC 11 tournament (Stockfish seemed to play a
little bit more actively than in previous seasons).
The patch does not change the play during match or blitz play, but gives
more options for correspondance players to decide for which color(s) they
would like to use contempt in analysis mode (infinite time). Here is a
description of the various options:
* Both : in analysis mode, use the contempt for both players (alternating)
* Off : in analysis mode, use the contempt for none of the players
* White : in analysis mode, White will play actively, Black will play passively
* Black : in analysis mode, Black will play actively, White will play passively
2018-04-18 09:30:00 -06:00
|
|
|
|
|
|
|
// In analysis mode, adjust contempt in accordance with user preference
|
|
|
|
if (Limits.infinite || Options["UCI_AnalyseMode"])
|
|
|
|
ct = Options["Analysis Contempt"] == "Off" ? 0
|
|
|
|
: Options["Analysis Contempt"] == "Both" ? ct
|
|
|
|
: Options["Analysis Contempt"] == "White" && us == BLACK ? -ct
|
|
|
|
: Options["Analysis Contempt"] == "Black" && us == WHITE ? -ct
|
|
|
|
: ct;
|
|
|
|
|
2019-03-31 03:47:36 -06:00
|
|
|
// Evaluation score is from the white point of view
|
Use per-thread dynamic contempt
We now use per-thread dynamic contempt. This patch has the following
effects:
* for Threads=1: **non-functional**
* for Threads>1:
* with MultiPV=1: **no regression, little to no ELO gain**
* with MultiPV>1: **clear improvement over master**
First, I tried testing at standard MultiPV=1 play with [0,5] bounds.
This yielded 2 yellow and 1 red test:
5+0.05, Threads=5:
LLR: -2.96 (-2.94,2.94) [0.00,5.00]
Total: 82689 W: 16439 L: 16190 D: 50060
http://tests.stockfishchess.org/tests/view/5aa93a5a0ebc5902952892e6
5+0.05, Threads=8:
LLR: -2.96 (-2.94,2.94) [0.00,5.00]
Total: 27164 W: 4974 L: 4983 D: 17207
http://tests.stockfishchess.org/tests/view/5ab2639b0ebc5902a6fbefd5
5+0.5, Threads=16:
LLR: -2.97 (-2.94,2.94) [0.00,5.00]
Total: 41396 W: 7127 L: 7082 D: 27187
http://tests.stockfishchess.org/tests/view/5ab124220ebc59029516cb62
Then, I tested with Skill Level=17 (implicitly MutliPV=4), showing
a clear improvement:
5+0.05, Threads=5:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 3498 W: 1316 L: 1135 D: 1047
http://tests.stockfishchess.org/tests/view/5ab4b6580ebc5902932aeca2
Next, I tested the patch with MultiPV=1 again, this time checking for
non-regression ([-3, 1]):
5+0.5, Threads=5:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 65575 W: 12786 L: 12745 D: 40044
http://tests.stockfishchess.org/tests/view/5ab4e8500ebc5902932aecb3
Finally, I ran some tests with fixed number of games, checking if
reverting dynamic contempt gains more elo with Skill Level=17 (i.e.
MultiPV) than applying the "prevScore" fix and this patch. These tests
showed, that this patch gains 15 ELO when playing with Skill Level=17:
5+0.05, Threads=3, "revert dynamic contempt" vs. "WITHOUT this patch":
ELO: -11.43 +-4.1 (95%) LOS: 0.0%
Total: 20000 W: 7085 L: 7743 D: 5172
http://tests.stockfishchess.org/tests/view/5ab636450ebc590295d88536
5+0.05, Threads=3, "revert dynamic contempt" vs. "WITH this patch":
ELO: -26.42 +-4.1 (95%) LOS: 0.0%
Total: 20000 W: 6661 L: 8179 D: 5160
http://tests.stockfishchess.org/tests/view/5ab62e680ebc590295d88524
---
***FAQ***
**Why should this be commited?**
I believe that the gain for multi-thread MultiPV search is a sufficient
justification for this otherwise neutral change. I also believe this
implementation of dynamic contempt is more logical, although this may
be just my opinion.
**Why is per-thread contempt better at MultiPV?**
A likely explanation for the gain in MultiPV mode is that during
search each thread independently switches between rootMoves and via
the shared contempt score skews each other's evaluation.
**Why were the tests done with Skill Level=17?**
This was originally suggested by @Hanamuke and the idea is that with
Skill Level Stockfish sometimes plays also moves it thinks are slightly
sub-optimal and thus the quality of all moves offered by the MultiPV
search is checked by the test.
**Why are the ELO differences so huge?**
This is most likely because of the nature of Skill Level mode --
since it slower and weaker than normal mode, bugs in evaluation have
much greater effect.
---
Closes https://github.com/official-stockfish/Stockfish/pull/1515.
No functional change -- in single thread mode.
2018-03-30 02:47:05 -06:00
|
|
|
contempt = (us == WHITE ? make_score(ct, ct / 2)
|
|
|
|
: -make_score(ct, ct / 2));
|
Introduce dynamic contempt
Make contempt dependent on the current score of the root position.
The idea is that we now use a linear formula like the following to decide
on the contempt to use during a search :
contempt = x + y * eval
where x is the base contempt set by the user in the "Contempt" UCI option,
and y * eval is the dynamic part which adapts itself to the estimation of
the evaluation of the root position returned by the search. In this patch,
we use x = 18 centipawns by default, and the y * eval correction can go
from -20 centipawns if the root eval is less than -2.0 pawns, up to +20
centipawns when the root eval is more than 2.0 pawns.
To summarize, the new contempt goes from -0.02 to 0.38 pawns, depending if
Stockfish is losing or winning, with an average value of 0.18 pawns by default.
STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 110052 W: 24614 L: 23938 D: 61500
http://tests.stockfishchess.org/tests/view/5a72e6020ebc590f2c86ea20
LTC:
LLR: 2.97 (-2.94,2.94) [0.00,5.00]
Total: 16470 W: 2896 L: 2705 D: 10869
http://tests.stockfishchess.org/tests/view/5a76c5b90ebc5902971a9830
A second match at LTC was organised against the current master:
ELO: 1.45 +-2.9 (95%) LOS: 84.0%
Total: 19369 W: 3350 L: 3269 D: 12750
http://tests.stockfishchess.org/tests/view/5a7acf980ebc5902971a9a2e
Finally, we checked that there is no apparent problem with multithreading,
despite the fact that some threads might have a slightly different contempt
level that the main thread.
Match of this version against master, both using 5 threads, time control 30+0.3:
ELO: 2.18 +-3.2 (95%) LOS: 90.8%
Total: 14840 W: 2502 L: 2409 D: 9929
http://tests.stockfishchess.org/tests/view/5a7bf3e80ebc5902971a9aa2
Include suggestions from Marco Costalba, Aram Tumanian, Ronald de Man, etc.
Bench: 5207156
2018-02-09 10:43:53 -07:00
|
|
|
|
Smarter time management near stop limit
This patch makes Stockfish search same depth again if > 60% of optimum time is
already used, instead of trying the next iteration. The idea is that the next
iteration will generally take about the same amount of time as has already been
used in total. When we are likely to begin the last iteration, as judged by total
time taken so far > 0.6 * optimum time, searching the last depth again instead of
increasing the depth still helps the other threads in lazy SMP and prepares better
move ordering for the next moves.
STC :
LLR: 2.95 (-2.94,2.94) {-1.00,3.00}
Total: 13436 W: 2695 L: 2558 D: 8183
Ptnml(0-2): 222, 1538, 3087, 1611, 253
https://tests.stockfishchess.org/tests/view/5e1618a761fe5f83a67dd964
LTC :
LLR: 2.94 (-2.94,2.94) {0.00,2.00}
Total: 32160 W: 4261 L: 4047 D: 23852
Ptnml(0-2): 211, 2988, 9448, 3135, 247
https://tests.stockfishchess.org/tests/view/5e162ca061fe5f83a67dd96d
The code was revised as suggested by @vondele for multithreading:
STC (8 threads):
LLR: 2.95 (-2.94,2.94) {0.00,2.00}
Total: 16640 W: 2049 L: 1885 D: 12706
Ptnml(0-2): 119, 1369, 5158, 1557, 108
https://tests.stockfishchess.org/tests/view/5e19826a2cc590e03c3c2f52
LTC (8 threads):
LLR: 2.95 (-2.94,2.94) {-1.00,3.00}
Total: 16536 W: 2758 L: 2629 D: 11149
Ptnml(0-2): 182, 1758, 4296, 1802, 224
https://tests.stockfishchess.org/tests/view/5e18b91a27dab692fcf9a140
Thanks to those discussing Stockfish lazy SMP on fishcooking which made me
try this, and to @vondele for suggestions and doing related tests.
See full discussion in the pull request thread:
https://github.com/official-stockfish/Stockfish/pull/2482
Bench: 4586187
2020-01-11 15:10:22 -07:00
|
|
|
int searchAgainCounter = 0;
|
|
|
|
|
2016-08-19 04:17:38 -06:00
|
|
|
// Iterative deepening loop until requested to stop or the target depth is reached
|
2019-09-28 14:27:23 -06:00
|
|
|
while ( ++rootDepth < MAX_PLY
|
2017-07-13 17:07:19 -06:00
|
|
|
&& !Threads.stop
|
2019-09-28 14:27:23 -06:00
|
|
|
&& !(Limits.depth && mainThread && rootDepth > Limits.depth))
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
{
|
|
|
|
// Age out PV variability metric
|
2015-12-23 02:07:54 -07:00
|
|
|
if (mainThread)
|
Use average bestMoveChanges across all threads #2072
The current update only by main thread depends on the luck of
whether main thread sees any/many changes to the best move or not.
It then makes large, lumpy changes to the time to be
used (1x, 2x, 3x, etc) depending on that sample of 1.
Use the average across all threads to get a more reliable
number with a smoother distribution.
STC @ 5+0.05 th 4 :
LLR: 2.95 (-2.94,2.94) [0.50,4.50]
Total: 51899 W: 11446 L: 11029 D: 29424
http://tests.stockfishchess.org/tests/view/5ca32ff20ebc5925cf0016fb
STC @ 5+0.05 th 8 :
LLR: 2.96 (-2.94,2.94) [0.50,4.50]
Total: 13851 W: 2843 L: 2620 D: 8388
http://tests.stockfishchess.org/tests/view/5ca35ae00ebc5925cf001adb
LTC @ 20+0.2 th 8 :
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 48527 W: 7941 L: 7635 D: 32951
http://tests.stockfishchess.org/tests/view/5ca37cb70ebc5925cf001cec
Further work:
Similar changes might be possible for the fallingEval and timeReduction calculations (and elsewhere?), using either the min, average or max values across all threads.
Bench 3506898
2019-04-03 01:35:55 -06:00
|
|
|
totBestMoveChanges /= 2;
|
2012-10-24 04:05:20 -06:00
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
// Save the last iteration's scores before first PV line is searched and
|
|
|
|
// all the move scores except the (new) PV are set to -VALUE_INFINITE.
|
|
|
|
for (RootMove& rm : rootMoves)
|
|
|
|
rm.previousScore = rm.score;
|
2013-08-24 10:29:44 -06:00
|
|
|
|
2018-06-02 09:41:37 -06:00
|
|
|
size_t pvFirst = 0;
|
|
|
|
pvLast = 0;
|
2018-04-18 10:38:38 -06:00
|
|
|
|
Smarter time management near stop limit
This patch makes Stockfish search same depth again if > 60% of optimum time is
already used, instead of trying the next iteration. The idea is that the next
iteration will generally take about the same amount of time as has already been
used in total. When we are likely to begin the last iteration, as judged by total
time taken so far > 0.6 * optimum time, searching the last depth again instead of
increasing the depth still helps the other threads in lazy SMP and prepares better
move ordering for the next moves.
STC :
LLR: 2.95 (-2.94,2.94) {-1.00,3.00}
Total: 13436 W: 2695 L: 2558 D: 8183
Ptnml(0-2): 222, 1538, 3087, 1611, 253
https://tests.stockfishchess.org/tests/view/5e1618a761fe5f83a67dd964
LTC :
LLR: 2.94 (-2.94,2.94) {0.00,2.00}
Total: 32160 W: 4261 L: 4047 D: 23852
Ptnml(0-2): 211, 2988, 9448, 3135, 247
https://tests.stockfishchess.org/tests/view/5e162ca061fe5f83a67dd96d
The code was revised as suggested by @vondele for multithreading:
STC (8 threads):
LLR: 2.95 (-2.94,2.94) {0.00,2.00}
Total: 16640 W: 2049 L: 1885 D: 12706
Ptnml(0-2): 119, 1369, 5158, 1557, 108
https://tests.stockfishchess.org/tests/view/5e19826a2cc590e03c3c2f52
LTC (8 threads):
LLR: 2.95 (-2.94,2.94) {-1.00,3.00}
Total: 16536 W: 2758 L: 2629 D: 11149
Ptnml(0-2): 182, 1758, 4296, 1802, 224
https://tests.stockfishchess.org/tests/view/5e18b91a27dab692fcf9a140
Thanks to those discussing Stockfish lazy SMP on fishcooking which made me
try this, and to @vondele for suggestions and doing related tests.
See full discussion in the pull request thread:
https://github.com/official-stockfish/Stockfish/pull/2482
Bench: 4586187
2020-01-11 15:10:22 -07:00
|
|
|
if (!Threads.increaseDepth)
|
|
|
|
searchAgainCounter++;
|
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
// MultiPV loop. We perform a full root search for each PV line
|
2018-06-02 09:41:37 -06:00
|
|
|
for (pvIdx = 0; pvIdx < multiPV && !Threads.stop; ++pvIdx)
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
{
|
2018-06-02 09:41:37 -06:00
|
|
|
if (pvIdx == pvLast)
|
2018-04-18 10:38:38 -06:00
|
|
|
{
|
2018-06-02 09:41:37 -06:00
|
|
|
pvFirst = pvLast;
|
|
|
|
for (pvLast++; pvLast < rootMoves.size(); pvLast++)
|
|
|
|
if (rootMoves[pvLast].tbRank != rootMoves[pvFirst].tbRank)
|
2018-04-18 10:38:38 -06:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
2017-07-13 17:30:03 -06:00
|
|
|
// Reset UCI info selDepth for each depth and each PV line
|
|
|
|
selDepth = 0;
|
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
// Reset aspiration window starting size
|
2019-09-28 14:27:23 -06:00
|
|
|
if (rootDepth >= 4)
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
{
|
2020-04-12 12:30:08 -06:00
|
|
|
Value prev = rootMoves[pvIdx].previousScore;
|
Assorted search parameter tune
STC https://tests.stockfishchess.org/tests/view/5f31219090816720665374ec
LLR: 2.96 (-2.94,2.94) {-0.50,1.50}
Total: 3376 W: 487 L: 359 D: 2530
Ptnml(0-2): 17, 253, 1042, 337, 39
LTC https://tests.stockfishchess.org/tests/view/5f3127f79081672066537502
LLR: 2.93 (-2.94,2.94) {0.25,1.75}
Total: 8360 W: 581 L: 475 D: 7304
Ptnml(0-2): 11, 407, 3238, 513, 11
closes https://github.com/official-stockfish/Stockfish/pull/2971
bench: 4733874
2020-08-10 07:38:44 -06:00
|
|
|
delta = Value(17);
|
2020-04-12 12:30:08 -06:00
|
|
|
alpha = std::max(prev - delta,-VALUE_INFINITE);
|
|
|
|
beta = std::min(prev + delta, VALUE_INFINITE);
|
Introduce dynamic contempt
Make contempt dependent on the current score of the root position.
The idea is that we now use a linear formula like the following to decide
on the contempt to use during a search :
contempt = x + y * eval
where x is the base contempt set by the user in the "Contempt" UCI option,
and y * eval is the dynamic part which adapts itself to the estimation of
the evaluation of the root position returned by the search. In this patch,
we use x = 18 centipawns by default, and the y * eval correction can go
from -20 centipawns if the root eval is less than -2.0 pawns, up to +20
centipawns when the root eval is more than 2.0 pawns.
To summarize, the new contempt goes from -0.02 to 0.38 pawns, depending if
Stockfish is losing or winning, with an average value of 0.18 pawns by default.
STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 110052 W: 24614 L: 23938 D: 61500
http://tests.stockfishchess.org/tests/view/5a72e6020ebc590f2c86ea20
LTC:
LLR: 2.97 (-2.94,2.94) [0.00,5.00]
Total: 16470 W: 2896 L: 2705 D: 10869
http://tests.stockfishchess.org/tests/view/5a76c5b90ebc5902971a9830
A second match at LTC was organised against the current master:
ELO: 1.45 +-2.9 (95%) LOS: 84.0%
Total: 19369 W: 3350 L: 3269 D: 12750
http://tests.stockfishchess.org/tests/view/5a7acf980ebc5902971a9a2e
Finally, we checked that there is no apparent problem with multithreading,
despite the fact that some threads might have a slightly different contempt
level that the main thread.
Match of this version against master, both using 5 threads, time control 30+0.3:
ELO: 2.18 +-3.2 (95%) LOS: 90.8%
Total: 14840 W: 2502 L: 2409 D: 9929
http://tests.stockfishchess.org/tests/view/5a7bf3e80ebc5902971a9aa2
Include suggestions from Marco Costalba, Aram Tumanian, Ronald de Man, etc.
Bench: 5207156
2018-02-09 10:43:53 -07:00
|
|
|
|
Fix dynamic contempt for MultiPV
Use rootMoves[PVIdx].previousScore instead of bestValue for
dynamic contempt. This is equivalent for MultiPV=1 (bench remained the
same, even for higher depths), but more correct for MultiPV.
STC (MultiPV=3):
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 2657 W: 1079 L: 898 D: 680
http://tests.stockfishchess.org/tests/view/5aaa47cb0ebc590297330403
LTC (MultiPV=3):
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 2390 W: 874 L: 706 D: 810
http://tests.stockfishchess.org/tests/view/5aaa593a0ebc59029733040b
VLTC 240+2.4 (MultiPV=3):
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 2399 W: 861 L: 694 D: 844
http://tests.stockfishchess.org/tests/view/5aaf983e0ebc5902a182131f
LTC (MultiPV=4, Skill Level=17):
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 747 W: 333 L: 175 D: 239
http://tests.stockfishchess.org/tests/view/5aabccee0ebc5902997ff006
Note: although the ELO differences seem huge, they are inflated by the
nature of Skill Level / MultiPV search, so I don't think they can be
reasonably compared with classic ELO strength.
See https://github.com/official-stockfish/Stockfish/pull/1491 for some
verifications searches with MultiPV = 10 at depths 12 and 24 from the
starting position and the position after 1.e4, comparing the outputs
of the full PV by the old master and by this patch.
No functional change for MultiPV=1
2018-03-14 09:47:45 -06:00
|
|
|
// Adjust contempt based on root move's previousScore (dynamic contempt)
|
Assorted search and eval parameter tune
Search and eval parameter tune.
STC https://tests.stockfishchess.org/tests/view/5fba850a67cbf42301d6b07d
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 24312 W: 2388 L: 2228 D: 19696
Ptnml(0-2): 85, 1800, 8241, 1930, 100
LTC https://tests.stockfishchess.org/tests/view/5fbad5ea67cbf42301d6b0fa
LLR: 2.95 (-2.94,2.94) {0.25,1.25}
Total: 88376 W: 3619 L: 3351 D: 81406
Ptnml(0-2): 56, 2977, 37849, 3255, 51
closes https://github.com/official-stockfish/Stockfish/pull/3232
bench: 3600361
2020-11-24 09:06:30 -07:00
|
|
|
int dct = ct + (113 - ct / 2) * prev / (abs(prev) + 147);
|
Introduce dynamic contempt
Make contempt dependent on the current score of the root position.
The idea is that we now use a linear formula like the following to decide
on the contempt to use during a search :
contempt = x + y * eval
where x is the base contempt set by the user in the "Contempt" UCI option,
and y * eval is the dynamic part which adapts itself to the estimation of
the evaluation of the root position returned by the search. In this patch,
we use x = 18 centipawns by default, and the y * eval correction can go
from -20 centipawns if the root eval is less than -2.0 pawns, up to +20
centipawns when the root eval is more than 2.0 pawns.
To summarize, the new contempt goes from -0.02 to 0.38 pawns, depending if
Stockfish is losing or winning, with an average value of 0.18 pawns by default.
STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 110052 W: 24614 L: 23938 D: 61500
http://tests.stockfishchess.org/tests/view/5a72e6020ebc590f2c86ea20
LTC:
LLR: 2.97 (-2.94,2.94) [0.00,5.00]
Total: 16470 W: 2896 L: 2705 D: 10869
http://tests.stockfishchess.org/tests/view/5a76c5b90ebc5902971a9830
A second match at LTC was organised against the current master:
ELO: 1.45 +-2.9 (95%) LOS: 84.0%
Total: 19369 W: 3350 L: 3269 D: 12750
http://tests.stockfishchess.org/tests/view/5a7acf980ebc5902971a9a2e
Finally, we checked that there is no apparent problem with multithreading,
despite the fact that some threads might have a slightly different contempt
level that the main thread.
Match of this version against master, both using 5 threads, time control 30+0.3:
ELO: 2.18 +-3.2 (95%) LOS: 90.8%
Total: 14840 W: 2502 L: 2409 D: 9929
http://tests.stockfishchess.org/tests/view/5a7bf3e80ebc5902971a9aa2
Include suggestions from Marco Costalba, Aram Tumanian, Ronald de Man, etc.
Bench: 5207156
2018-02-09 10:43:53 -07:00
|
|
|
|
Analysis Contempt combo box
This patch introduces an Analysis Contempt UCI combo box to control
the behaviour of contempt during analysis. The possible values are
Both, Off, White, Black. Technically, the engine is supposed to be in
analysis mode if UCI_AnalyseMode is set by the graphical user interface
or if the user has chosen infinite analysis mode ("go infinite").
Credits: the idea for the combo box is due to Michel Van den Bergh.
No functional change (outside analysis mode).
-----------------------------------------------------
The so-called "contempt" is an optimism value that the engine adds
to one color to avoid simplifications and keep tension in the position
during its search. It was introduced in Stockfish 9 and seemed to give
good results during the TCEC 11 tournament (Stockfish seemed to play a
little bit more actively than in previous seasons).
The patch does not change the play during match or blitz play, but gives
more options for correspondance players to decide for which color(s) they
would like to use contempt in analysis mode (infinite time). Here is a
description of the various options:
* Both : in analysis mode, use the contempt for both players (alternating)
* Off : in analysis mode, use the contempt for none of the players
* White : in analysis mode, White will play actively, Black will play passively
* Black : in analysis mode, Black will play actively, White will play passively
2018-04-18 09:30:00 -06:00
|
|
|
contempt = (us == WHITE ? make_score(dct, dct / 2)
|
|
|
|
: -make_score(dct, dct / 2));
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
}
|
2009-04-11 07:46:35 -06:00
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
// Start with a small aspiration window and, in the case of a fail
|
2018-02-12 14:57:42 -07:00
|
|
|
// high/low, re-search with a bigger window until we don't fail
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
// high/low anymore.
|
Simplify reduction for consecutive fails
Revert the heuristic introduced in #3184, by which we reduced more
the late sons of the root position after consecutive fail highs.
---
Before new net architecture:
STC:
LLR: 2.95 (-2.94,2.94) <-2.50,0.50>
Total: 226336 W: 20373 L: 20500 D: 185463
Ptnml(0-2): 755, 16087, 79595, 15992, 739
https://tests.stockfishchess.org/tests/view/609dec205085663412d08e9d
LTC:
LLR: 2.93 (-2.94,2.94) <-2.50,0.50>
Total: 67432 W: 2411 L: 2375 D: 62646
Ptnml(0-2): 33, 1944, 29714, 2004, 21
https://tests.stockfishchess.org/tests/view/609ee30f5085663412d08fc3
---
After new net architecture:
STC:
LLR: 2.95 (-2.94,2.94) <-2.50,0.50>
Total: 141752 W: 11591 L: 11617 D: 118544
Ptnml(0-2): 387, 9231, 51674, 9189, 395
https://tests.stockfishchess.org/tests/view/60a4320ace8ea25a3ef03cfd
LTC:
LLR: 2.95 (-2.94,2.94) <-2.50,0.50>
Total: 294072 W: 9825 L: 9950 D: 274297
Ptnml(0-2): 121, 8610, 129681, 8521, 103
https://tests.stockfishchess.org/tests/view/60a51b5ece8ea25a3ef03dcd
---
closes https://github.com/official-stockfish/Stockfish/pull/3490
Bench: 3752892
2021-05-21 23:41:52 -06:00
|
|
|
int failedHighCnt = 0;
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
while (true)
|
|
|
|
{
|
Smarter time management near stop limit
This patch makes Stockfish search same depth again if > 60% of optimum time is
already used, instead of trying the next iteration. The idea is that the next
iteration will generally take about the same amount of time as has already been
used in total. When we are likely to begin the last iteration, as judged by total
time taken so far > 0.6 * optimum time, searching the last depth again instead of
increasing the depth still helps the other threads in lazy SMP and prepares better
move ordering for the next moves.
STC :
LLR: 2.95 (-2.94,2.94) {-1.00,3.00}
Total: 13436 W: 2695 L: 2558 D: 8183
Ptnml(0-2): 222, 1538, 3087, 1611, 253
https://tests.stockfishchess.org/tests/view/5e1618a761fe5f83a67dd964
LTC :
LLR: 2.94 (-2.94,2.94) {0.00,2.00}
Total: 32160 W: 4261 L: 4047 D: 23852
Ptnml(0-2): 211, 2988, 9448, 3135, 247
https://tests.stockfishchess.org/tests/view/5e162ca061fe5f83a67dd96d
The code was revised as suggested by @vondele for multithreading:
STC (8 threads):
LLR: 2.95 (-2.94,2.94) {0.00,2.00}
Total: 16640 W: 2049 L: 1885 D: 12706
Ptnml(0-2): 119, 1369, 5158, 1557, 108
https://tests.stockfishchess.org/tests/view/5e19826a2cc590e03c3c2f52
LTC (8 threads):
LLR: 2.95 (-2.94,2.94) {-1.00,3.00}
Total: 16536 W: 2758 L: 2629 D: 11149
Ptnml(0-2): 182, 1758, 4296, 1802, 224
https://tests.stockfishchess.org/tests/view/5e18b91a27dab692fcf9a140
Thanks to those discussing Stockfish lazy SMP on fishcooking which made me
try this, and to @vondele for suggestions and doing related tests.
See full discussion in the pull request thread:
https://github.com/official-stockfish/Stockfish/pull/2482
Bench: 4586187
2020-01-11 15:10:22 -07:00
|
|
|
Depth adjustedDepth = std::max(1, rootDepth - failedHighCnt - searchAgainCounter);
|
2021-02-26 02:02:13 -07:00
|
|
|
bestValue = Stockfish::search<PV>(rootPos, ss, alpha, beta, adjustedDepth, false);
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
|
|
|
|
// Bring the best move to the front. It is critical that sorting
|
|
|
|
// is done with a stable algorithm because all the values but the
|
|
|
|
// first and eventually the new best one are set to -VALUE_INFINITE
|
|
|
|
// and we want to keep the same order for all the moves except the
|
|
|
|
// new PV that goes to the front. Note that in case of MultiPV
|
|
|
|
// search the already searched PV lines are preserved.
|
2018-06-02 09:41:37 -06:00
|
|
|
std::stable_sort(rootMoves.begin() + pvIdx, rootMoves.begin() + pvLast);
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
|
2018-02-12 14:57:42 -07:00
|
|
|
// If search has been stopped, we break immediately. Sorting is
|
|
|
|
// safe because RootMoves is still valid, although it refers to
|
|
|
|
// the previous iteration.
|
2017-07-13 17:07:19 -06:00
|
|
|
if (Threads.stop)
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
break;
|
2011-02-28 12:17:57 -07:00
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
// When failing high/low give some update (without cluttering
|
|
|
|
// the UI) before a re-search.
|
2015-12-23 02:07:54 -07:00
|
|
|
if ( mainThread
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
&& multiPV == 1
|
|
|
|
&& (bestValue <= alpha || bestValue >= beta)
|
|
|
|
&& Time.elapsed() > 3000)
|
Fix issues from using adjustedDepth too broadly
The recently committed Fail-High patch (081af9080542a0d076a5482da37103a96ee15f64)
had a number of changes beyond adjusting the depth of search on fail high, with
some undesirable side effects.
1) Decreasing depth on PV output, confusing GUIs and players alike as described in
issue #1787. The depth printed is anyway a convention, let's consider adjustedDepth
an implementation detail, and continue to print rootDepth. Depth, nodes, time and
move quality all increase as we compute more. (fixing this output has no effect on
play).
2) Fixes go depth output (now based on rootDepth again, no effect on play), also
reported in issue #1787
3) The depth lastBestDepth is used to compute how long a move is stable, a new move
found during fail-high is incorrectly considered stable if based on adjustedDepth
instead of rootDepth (this changes time management). Reverting this passed STC
and LTC:
STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 82982 W: 17810 L: 17808 D: 47364
http://tests.stockfishchess.org/tests/view/5bd391a80ebc595e0ae1e993
LTC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 109083 W: 17602 L: 17619 D: 73862
http://tests.stockfishchess.org/tests/view/5bd40c820ebc595e0ae1f1fb
4) In the thread voting scheme, the rank of the fail-high thread is now artificially
low, incorrectly since the quality of the move is much better than what adjustedDepth
suggests (e.g. if it takes 10 iterations to find VALUE_KNOWN_WIN, it has very low
depth). Further evidence comes from a test that showed that the move of highest
depth is not better than that of the last PV (which is potentially of much lower
adjustedDepth).
I.e. this test http://tests.stockfishchess.org/tests/view/5bd37a120ebc595e0ae1e7c3
failed SPRT[0, 5]:
LLR: -2.95 (-2.94,2.94) [0.00,5.00]
Total: 10609 W: 2266 L: 2345 D: 5998
In a running 5+0.05 th 8 test (more than 10000 games) a positive Elo estimate is
shown (strong enough for a [-3,1], possibly not [0,4]):
http://tests.stockfishchess.org/tests/view/5bd421be0ebc595e0ae1f315
LLR: -0.13 (-2.94,2.94) [0.00,4.00]
Total: 13644 W: 2573 L: 2532 D: 8539
Elo 1.04 [-2.52,4.61] / LOS 71%
Thus, restore old behavior as a bugfix, keeping the core of the fail-high patch
idea as resolving scheme. This is non-functional for bench, but changes searches
via time management and in the threaded case.
Bench: 3556672
2018-10-28 08:25:15 -06:00
|
|
|
sync_cout << UCI::pv(rootPos, rootDepth, alpha, beta) << sync_endl;
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
|
|
|
|
// In case of failing low/high increase aspiration window and
|
|
|
|
// re-search, otherwise exit the loop.
|
|
|
|
if (bestValue <= alpha)
|
|
|
|
{
|
|
|
|
beta = (alpha + beta) / 2;
|
|
|
|
alpha = std::max(bestValue - delta, -VALUE_INFINITE);
|
2012-10-24 04:05:20 -06:00
|
|
|
|
2019-03-31 09:33:32 -06:00
|
|
|
failedHighCnt = 0;
|
2015-12-23 02:07:54 -07:00
|
|
|
if (mainThread)
|
Simplify pondering time management (#1899)
stopOnPonderhit is used to stop search quickly on a ponderhit. It is set by mainThread as part of its time management. However, master employs it as a signal between mainThread and the UCI thread. This is not necessary, it is sufficient for the UCI thread to signal that pondering finished, and mainThread should do its usual time-keeping job, and in this case stop immediately.
This patch implements this, removing stopOnPonderHit as an atomic variable from the ThreadPool,
and moving it as a normal variable to mainThread, reducing its scope. In MainThread::check_time() the search is stopped immediately if ponder switches to false, and the variable stopOnPonderHit is set.
Furthermore, ponder has been moved to mainThread, as the variable is only used to exchange signals between the UCI thread and mainThread.
The version has been tested locally (as fishtest doesn't support ponder):
Score of ponderSimp vs master: 2616 - 2528 - 8630 [0.503] 13774
Elo difference: 2.22 +/- 3.54
which indicates no regression.
No functional change.
2019-01-20 11:14:24 -07:00
|
|
|
mainThread->stopOnPonderhit = false;
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
}
|
|
|
|
else if (bestValue >= beta)
|
2018-10-19 02:33:01 -06:00
|
|
|
{
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
beta = std::min(bestValue + delta, VALUE_INFINITE);
|
2019-03-31 09:33:32 -06:00
|
|
|
++failedHighCnt;
|
2018-10-19 02:33:01 -06:00
|
|
|
}
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
else
|
|
|
|
break;
|
2013-02-03 03:14:21 -07:00
|
|
|
|
2015-10-20 20:46:06 -06:00
|
|
|
delta += delta / 4 + 5;
|
2014-11-10 06:46:05 -07:00
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
assert(alpha >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
|
|
|
|
}
|
2009-04-11 07:46:35 -06:00
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
// Sort the PV lines searched so far and update the GUI
|
2018-06-02 09:41:37 -06:00
|
|
|
std::stable_sort(rootMoves.begin() + pvFirst, rootMoves.begin() + pvIdx + 1);
|
2011-04-02 02:05:53 -06:00
|
|
|
|
2017-08-18 11:38:18 -06:00
|
|
|
if ( mainThread
|
2018-06-02 09:41:37 -06:00
|
|
|
&& (Threads.stop || pvIdx + 1 == multiPV || Time.elapsed() > 3000))
|
Fix issues from using adjustedDepth too broadly
The recently committed Fail-High patch (081af9080542a0d076a5482da37103a96ee15f64)
had a number of changes beyond adjusting the depth of search on fail high, with
some undesirable side effects.
1) Decreasing depth on PV output, confusing GUIs and players alike as described in
issue #1787. The depth printed is anyway a convention, let's consider adjustedDepth
an implementation detail, and continue to print rootDepth. Depth, nodes, time and
move quality all increase as we compute more. (fixing this output has no effect on
play).
2) Fixes go depth output (now based on rootDepth again, no effect on play), also
reported in issue #1787
3) The depth lastBestDepth is used to compute how long a move is stable, a new move
found during fail-high is incorrectly considered stable if based on adjustedDepth
instead of rootDepth (this changes time management). Reverting this passed STC
and LTC:
STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 82982 W: 17810 L: 17808 D: 47364
http://tests.stockfishchess.org/tests/view/5bd391a80ebc595e0ae1e993
LTC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 109083 W: 17602 L: 17619 D: 73862
http://tests.stockfishchess.org/tests/view/5bd40c820ebc595e0ae1f1fb
4) In the thread voting scheme, the rank of the fail-high thread is now artificially
low, incorrectly since the quality of the move is much better than what adjustedDepth
suggests (e.g. if it takes 10 iterations to find VALUE_KNOWN_WIN, it has very low
depth). Further evidence comes from a test that showed that the move of highest
depth is not better than that of the last PV (which is potentially of much lower
adjustedDepth).
I.e. this test http://tests.stockfishchess.org/tests/view/5bd37a120ebc595e0ae1e7c3
failed SPRT[0, 5]:
LLR: -2.95 (-2.94,2.94) [0.00,5.00]
Total: 10609 W: 2266 L: 2345 D: 5998
In a running 5+0.05 th 8 test (more than 10000 games) a positive Elo estimate is
shown (strong enough for a [-3,1], possibly not [0,4]):
http://tests.stockfishchess.org/tests/view/5bd421be0ebc595e0ae1f315
LLR: -0.13 (-2.94,2.94) [0.00,4.00]
Total: 13644 W: 2573 L: 2532 D: 8539
Elo 1.04 [-2.52,4.61] / LOS 71%
Thus, restore old behavior as a bugfix, keeping the core of the fail-high patch
idea as resolving scheme. This is non-functional for bench, but changes searches
via time management and in the threaded case.
Bench: 3556672
2018-10-28 08:25:15 -06:00
|
|
|
sync_cout << UCI::pv(rootPos, rootDepth, alpha, beta) << sync_endl;
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
}
|
2015-01-25 03:07:43 -07:00
|
|
|
|
2017-07-13 17:07:19 -06:00
|
|
|
if (!Threads.stop)
|
Fix issues from using adjustedDepth too broadly
The recently committed Fail-High patch (081af9080542a0d076a5482da37103a96ee15f64)
had a number of changes beyond adjusting the depth of search on fail high, with
some undesirable side effects.
1) Decreasing depth on PV output, confusing GUIs and players alike as described in
issue #1787. The depth printed is anyway a convention, let's consider adjustedDepth
an implementation detail, and continue to print rootDepth. Depth, nodes, time and
move quality all increase as we compute more. (fixing this output has no effect on
play).
2) Fixes go depth output (now based on rootDepth again, no effect on play), also
reported in issue #1787
3) The depth lastBestDepth is used to compute how long a move is stable, a new move
found during fail-high is incorrectly considered stable if based on adjustedDepth
instead of rootDepth (this changes time management). Reverting this passed STC
and LTC:
STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 82982 W: 17810 L: 17808 D: 47364
http://tests.stockfishchess.org/tests/view/5bd391a80ebc595e0ae1e993
LTC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 109083 W: 17602 L: 17619 D: 73862
http://tests.stockfishchess.org/tests/view/5bd40c820ebc595e0ae1f1fb
4) In the thread voting scheme, the rank of the fail-high thread is now artificially
low, incorrectly since the quality of the move is much better than what adjustedDepth
suggests (e.g. if it takes 10 iterations to find VALUE_KNOWN_WIN, it has very low
depth). Further evidence comes from a test that showed that the move of highest
depth is not better than that of the last PV (which is potentially of much lower
adjustedDepth).
I.e. this test http://tests.stockfishchess.org/tests/view/5bd37a120ebc595e0ae1e7c3
failed SPRT[0, 5]:
LLR: -2.95 (-2.94,2.94) [0.00,5.00]
Total: 10609 W: 2266 L: 2345 D: 5998
In a running 5+0.05 th 8 test (more than 10000 games) a positive Elo estimate is
shown (strong enough for a [-3,1], possibly not [0,4]):
http://tests.stockfishchess.org/tests/view/5bd421be0ebc595e0ae1f315
LLR: -0.13 (-2.94,2.94) [0.00,4.00]
Total: 13644 W: 2573 L: 2532 D: 8539
Elo 1.04 [-2.52,4.61] / LOS 71%
Thus, restore old behavior as a bugfix, keeping the core of the fail-high patch
idea as resolving scheme. This is non-functional for bench, but changes searches
via time management and in the threaded case.
Bench: 3556672
2018-10-28 08:25:15 -06:00
|
|
|
completedDepth = rootDepth;
|
2015-11-02 02:58:18 -07:00
|
|
|
|
Replace easyMove with simple scheme
Reduces time for a stable bestMove, giving some of the won time for the next move.
the version before the pvDraw passed both STC and LTC
passed STC:
http://tests.stockfishchess.org/tests/view/59e98d5a0ebc590ccbb896ec
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 78561 W: 13945 L: 13921 D: 50695
elo = 0.106 +- 1.445 LOS: 55.716%
passed LTC:
http://tests.stockfishchess.org/tests/view/59eb9df90ebc590ccbb897ae
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 29056 W: 3640 L: 3530 D: 21886
elo = 1.315 +- 1.982 LOS: 90.314%
This version, rebased on pvDrawPR with the obvious change, was verified again on STC:
http://tests.stockfishchess.org/tests/view/59ee104e0ebc590ccbb89899
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 19890 W: 3648 L: 3525 D: 12717
elo = 2.149 +- 2.895 LOS: 92.692%
and LTC:
http://tests.stockfishchess.org/tests/view/59f9673a0ebc590ccbb89ea0
Total : 17966
Win : 2273 ( 12.652%)
Loss : 2149 ( 11.961%)
Draw : 13544 ( 75.387%)
Score : 50.345%
Sensitivity : 0.014%
2*(W-L)/(W+L) : 5.608%
LLR [-3.0, 1.0] : 2.95
BayesElo range : [ -1.161, 4.876, 10.830] (DrawElo: 341.132)
LogisticElo range : [ -0.501, 2.105, 4.677]
LOS : 94.369 %
LTC again:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 17966 W: 2273 L: 2149 D: 13544
LogisticElo range : [ -0.501, 2.105, 4.677]
LOS : 94.369 %
unchanged bench: 5234652
2017-11-03 06:51:53 -06:00
|
|
|
if (rootMoves[0].pv[0] != lastBestMove) {
|
|
|
|
lastBestMove = rootMoves[0].pv[0];
|
Fix issues from using adjustedDepth too broadly
The recently committed Fail-High patch (081af9080542a0d076a5482da37103a96ee15f64)
had a number of changes beyond adjusting the depth of search on fail high, with
some undesirable side effects.
1) Decreasing depth on PV output, confusing GUIs and players alike as described in
issue #1787. The depth printed is anyway a convention, let's consider adjustedDepth
an implementation detail, and continue to print rootDepth. Depth, nodes, time and
move quality all increase as we compute more. (fixing this output has no effect on
play).
2) Fixes go depth output (now based on rootDepth again, no effect on play), also
reported in issue #1787
3) The depth lastBestDepth is used to compute how long a move is stable, a new move
found during fail-high is incorrectly considered stable if based on adjustedDepth
instead of rootDepth (this changes time management). Reverting this passed STC
and LTC:
STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 82982 W: 17810 L: 17808 D: 47364
http://tests.stockfishchess.org/tests/view/5bd391a80ebc595e0ae1e993
LTC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 109083 W: 17602 L: 17619 D: 73862
http://tests.stockfishchess.org/tests/view/5bd40c820ebc595e0ae1f1fb
4) In the thread voting scheme, the rank of the fail-high thread is now artificially
low, incorrectly since the quality of the move is much better than what adjustedDepth
suggests (e.g. if it takes 10 iterations to find VALUE_KNOWN_WIN, it has very low
depth). Further evidence comes from a test that showed that the move of highest
depth is not better than that of the last PV (which is potentially of much lower
adjustedDepth).
I.e. this test http://tests.stockfishchess.org/tests/view/5bd37a120ebc595e0ae1e7c3
failed SPRT[0, 5]:
LLR: -2.95 (-2.94,2.94) [0.00,5.00]
Total: 10609 W: 2266 L: 2345 D: 5998
In a running 5+0.05 th 8 test (more than 10000 games) a positive Elo estimate is
shown (strong enough for a [-3,1], possibly not [0,4]):
http://tests.stockfishchess.org/tests/view/5bd421be0ebc595e0ae1f315
LLR: -0.13 (-2.94,2.94) [0.00,4.00]
Total: 13644 W: 2573 L: 2532 D: 8539
Elo 1.04 [-2.52,4.61] / LOS 71%
Thus, restore old behavior as a bugfix, keeping the core of the fail-high patch
idea as resolving scheme. This is non-functional for bench, but changes searches
via time management and in the threaded case.
Bench: 3556672
2018-10-28 08:25:15 -06:00
|
|
|
lastBestMoveDepth = rootDepth;
|
Replace easyMove with simple scheme
Reduces time for a stable bestMove, giving some of the won time for the next move.
the version before the pvDraw passed both STC and LTC
passed STC:
http://tests.stockfishchess.org/tests/view/59e98d5a0ebc590ccbb896ec
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 78561 W: 13945 L: 13921 D: 50695
elo = 0.106 +- 1.445 LOS: 55.716%
passed LTC:
http://tests.stockfishchess.org/tests/view/59eb9df90ebc590ccbb897ae
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 29056 W: 3640 L: 3530 D: 21886
elo = 1.315 +- 1.982 LOS: 90.314%
This version, rebased on pvDrawPR with the obvious change, was verified again on STC:
http://tests.stockfishchess.org/tests/view/59ee104e0ebc590ccbb89899
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 19890 W: 3648 L: 3525 D: 12717
elo = 2.149 +- 2.895 LOS: 92.692%
and LTC:
http://tests.stockfishchess.org/tests/view/59f9673a0ebc590ccbb89ea0
Total : 17966
Win : 2273 ( 12.652%)
Loss : 2149 ( 11.961%)
Draw : 13544 ( 75.387%)
Score : 50.345%
Sensitivity : 0.014%
2*(W-L)/(W+L) : 5.608%
LLR [-3.0, 1.0] : 2.95
BayesElo range : [ -1.161, 4.876, 10.830] (DrawElo: 341.132)
LogisticElo range : [ -0.501, 2.105, 4.677]
LOS : 94.369 %
LTC again:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 17966 W: 2273 L: 2149 D: 13544
LogisticElo range : [ -0.501, 2.105, 4.677]
LOS : 94.369 %
unchanged bench: 5234652
2017-11-03 06:51:53 -06:00
|
|
|
}
|
|
|
|
|
2017-08-18 11:38:18 -06:00
|
|
|
// Have we found a "mate in x"?
|
|
|
|
if ( Limits.mate
|
|
|
|
&& bestValue >= VALUE_MATE_IN_MAX_PLY
|
|
|
|
&& VALUE_MATE - bestValue <= 2 * Limits.mate)
|
|
|
|
Threads.stop = true;
|
|
|
|
|
2015-12-23 02:07:54 -07:00
|
|
|
if (!mainThread)
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
continue;
|
2015-03-12 13:49:30 -06:00
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
// If skill level is enabled and time is up, pick a sub-optimal best move
|
2015-10-23 23:27:24 -06:00
|
|
|
if (skill.enabled() && skill.time_to_pick(rootDepth))
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
skill.pick_best(multiPV);
|
|
|
|
|
|
|
|
// Do we have time for the next iteration? Can we stop searching now?
|
2018-02-12 14:57:42 -07:00
|
|
|
if ( Limits.use_time_management()
|
|
|
|
&& !Threads.stop
|
Simplify pondering time management (#1899)
stopOnPonderhit is used to stop search quickly on a ponderhit. It is set by mainThread as part of its time management. However, master employs it as a signal between mainThread and the UCI thread. This is not necessary, it is sufficient for the UCI thread to signal that pondering finished, and mainThread should do its usual time-keeping job, and in this case stop immediately.
This patch implements this, removing stopOnPonderHit as an atomic variable from the ThreadPool,
and moving it as a normal variable to mainThread, reducing its scope. In MainThread::check_time() the search is stopped immediately if ponder switches to false, and the variable stopOnPonderHit is set.
Furthermore, ponder has been moved to mainThread, as the variable is only used to exchange signals between the UCI thread and mainThread.
The version has been tested locally (as fishtest doesn't support ponder):
Score of ponderSimp vs master: 2616 - 2528 - 8630 [0.503] 13774
Elo difference: 2.22 +/- 3.54
which indicates no regression.
No functional change.
2019-01-20 11:14:24 -07:00
|
|
|
&& !mainThread->stopOnPonderhit)
|
2019-01-01 06:10:26 -07:00
|
|
|
{
|
Assorted search parameter tune
STC https://tests.stockfishchess.org/tests/view/5f31219090816720665374ec
LLR: 2.96 (-2.94,2.94) {-0.50,1.50}
Total: 3376 W: 487 L: 359 D: 2530
Ptnml(0-2): 17, 253, 1042, 337, 39
LTC https://tests.stockfishchess.org/tests/view/5f3127f79081672066537502
LLR: 2.93 (-2.94,2.94) {0.25,1.75}
Total: 8360 W: 581 L: 475 D: 7304
Ptnml(0-2): 11, 407, 3238, 513, 11
closes https://github.com/official-stockfish/Stockfish/pull/2971
bench: 4733874
2020-08-10 07:38:44 -06:00
|
|
|
double fallingEval = (318 + 6 * (mainThread->bestPreviousScore - bestValue)
|
|
|
|
+ 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 825.0;
|
2020-07-11 08:59:33 -06:00
|
|
|
fallingEval = std::clamp(fallingEval, 0.5, 1.5);
|
2019-01-01 06:10:26 -07:00
|
|
|
|
|
|
|
// If the bestMove is stable over several iterations, reduce time accordingly
|
Assorted search parameter tune
STC https://tests.stockfishchess.org/tests/view/5f31219090816720665374ec
LLR: 2.96 (-2.94,2.94) {-0.50,1.50}
Total: 3376 W: 487 L: 359 D: 2530
Ptnml(0-2): 17, 253, 1042, 337, 39
LTC https://tests.stockfishchess.org/tests/view/5f3127f79081672066537502
LLR: 2.93 (-2.94,2.94) {0.25,1.75}
Total: 8360 W: 581 L: 475 D: 7304
Ptnml(0-2): 11, 407, 3238, 513, 11
closes https://github.com/official-stockfish/Stockfish/pull/2971
bench: 4733874
2020-08-10 07:38:44 -06:00
|
|
|
timeReduction = lastBestMoveDepth + 9 < completedDepth ? 1.92 : 0.95;
|
|
|
|
double reduction = (1.47 + mainThread->previousTimeReduction) / (2.32 * timeReduction);
|
2019-01-01 06:10:26 -07:00
|
|
|
|
|
|
|
// Use part of the gained time from a previous stable move for the current move
|
Use average bestMoveChanges across all threads #2072
The current update only by main thread depends on the luck of
whether main thread sees any/many changes to the best move or not.
It then makes large, lumpy changes to the time to be
used (1x, 2x, 3x, etc) depending on that sample of 1.
Use the average across all threads to get a more reliable
number with a smoother distribution.
STC @ 5+0.05 th 4 :
LLR: 2.95 (-2.94,2.94) [0.50,4.50]
Total: 51899 W: 11446 L: 11029 D: 29424
http://tests.stockfishchess.org/tests/view/5ca32ff20ebc5925cf0016fb
STC @ 5+0.05 th 8 :
LLR: 2.96 (-2.94,2.94) [0.50,4.50]
Total: 13851 W: 2843 L: 2620 D: 8388
http://tests.stockfishchess.org/tests/view/5ca35ae00ebc5925cf001adb
LTC @ 20+0.2 th 8 :
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 48527 W: 7941 L: 7635 D: 32951
http://tests.stockfishchess.org/tests/view/5ca37cb70ebc5925cf001cec
Further work:
Similar changes might be possible for the fallingEval and timeReduction calculations (and elsewhere?), using either the min, average or max values across all threads.
Bench 3506898
2019-04-03 01:35:55 -06:00
|
|
|
for (Thread* th : Threads)
|
2019-04-05 18:03:15 -06:00
|
|
|
{
|
Use average bestMoveChanges across all threads #2072
The current update only by main thread depends on the luck of
whether main thread sees any/many changes to the best move or not.
It then makes large, lumpy changes to the time to be
used (1x, 2x, 3x, etc) depending on that sample of 1.
Use the average across all threads to get a more reliable
number with a smoother distribution.
STC @ 5+0.05 th 4 :
LLR: 2.95 (-2.94,2.94) [0.50,4.50]
Total: 51899 W: 11446 L: 11029 D: 29424
http://tests.stockfishchess.org/tests/view/5ca32ff20ebc5925cf0016fb
STC @ 5+0.05 th 8 :
LLR: 2.96 (-2.94,2.94) [0.50,4.50]
Total: 13851 W: 2843 L: 2620 D: 8388
http://tests.stockfishchess.org/tests/view/5ca35ae00ebc5925cf001adb
LTC @ 20+0.2 th 8 :
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 48527 W: 7941 L: 7635 D: 32951
http://tests.stockfishchess.org/tests/view/5ca37cb70ebc5925cf001cec
Further work:
Similar changes might be possible for the fallingEval and timeReduction calculations (and elsewhere?), using either the min, average or max values across all threads.
Bench 3506898
2019-04-03 01:35:55 -06:00
|
|
|
totBestMoveChanges += th->bestMoveChanges;
|
2019-04-05 18:03:15 -06:00
|
|
|
th->bestMoveChanges = 0;
|
|
|
|
}
|
Use 2 * bestMoveChanges.
NNUE appears to provide a more stable eval than the classic eval,
so the time use dependencies on bestMoveChanges, fallingEval,
etc may need to change to make the best use of available time.
This change doubles the effect of totBestMoveChanges when giving
more time because the choice of best move is unstable.
STC:
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 101928 W: 11995 L: 11698 D: 78235 Elo +0.78
Ptnml(0-2): 592, 8707, 32103, 8936, 626
https://tests.stockfishchess.org/tests/view/5f538a462d02727c56b36cec
LTC:
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 186392 W: 10383 L: 9877 D: 166132 Elo +0.81
Ptnml(0-2): 207, 8370, 75539, 8870, 210
https://tests.stockfishchess.org/tests/view/5f54a9712d02727c56b36d5a
closes https://github.com/official-stockfish/Stockfish/pull/3119
Bench 4222126
2020-09-10 14:10:57 -06:00
|
|
|
double bestMoveInstability = 1 + 2 * totBestMoveChanges / Threads.size();
|
2019-01-01 06:10:26 -07:00
|
|
|
|
Change handling the special case of a single legal move.
Using no searching time in case of a single legal move is not beneficial from
a strength point of view, and this special case can be easily removed:
STC:
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 22472 W: 2458 L: 2357 D: 17657
Ptnml(0-2): 106, 1733, 7453, 1842, 102
https://tests.stockfishchess.org/tests/view/5f926cbc81eda81bd78cb6df
LTC:
LLR: 2.94 (-2.94,2.94) {-0.75,0.25}
Total: 37880 W: 1736 L: 1682 D: 34462
Ptnml(0-2): 22, 1392, 16057, 1448, 21
https://tests.stockfishchess.org/tests/view/5f92a26081eda81bd78cb6fe
The advantage of using the normal time management for a single legal move is that scores
reported for that move are reasonable, not searching leads to artifacts during games
(see e.g. https://tcec-chess.com/#div=sf&game=96&season=19)
The disadvantage of using normal time management of a single legal move is that thinking
times can be unnaturally long, making it 'painful to watch' in online tournaments.
This patch uses normal time management, but caps the used time to 500ms.
This should lead to reasonable scores, and be hardly perceptible.
closes https://github.com/official-stockfish/Stockfish/pull/3195
closes https://github.com/official-stockfish/Stockfish/pull/3183
variant of a patch suggested by SFisGOD
No functional change.
2020-10-22 23:39:35 -06:00
|
|
|
double totalTime = Time.optimum() * fallingEval * reduction * bestMoveInstability;
|
Minimal thinking time, even if only one rootMove.
without search, the eval returned can be misleading (e.g. mate instead of draw),
leading to wrong adjudication. With a minimal search, this is avoided.
This patch leads to 1ms long searches if there is only 1 move,
similar patches all indicate a small Elo gain.
Fixes https://github.com/official-stockfish/Stockfish/issues/2707
Passed non-regression STC:
LLR: 2.93 (-2.94,2.94) {-1.50,0.50}
Total: 22312 W: 4350 L: 4204 D: 13758
Ptnml(0-2): 323, 2488, 5437, 2536, 372
https://tests.stockfishchess.org/tests/view/5ed562b0f29b40b0fc95a7d0
closes https://github.com/official-stockfish/Stockfish/pull/2709
Bench: 4733799
2020-05-31 08:51:38 -06:00
|
|
|
|
Change handling the special case of a single legal move.
Using no searching time in case of a single legal move is not beneficial from
a strength point of view, and this special case can be easily removed:
STC:
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 22472 W: 2458 L: 2357 D: 17657
Ptnml(0-2): 106, 1733, 7453, 1842, 102
https://tests.stockfishchess.org/tests/view/5f926cbc81eda81bd78cb6df
LTC:
LLR: 2.94 (-2.94,2.94) {-0.75,0.25}
Total: 37880 W: 1736 L: 1682 D: 34462
Ptnml(0-2): 22, 1392, 16057, 1448, 21
https://tests.stockfishchess.org/tests/view/5f92a26081eda81bd78cb6fe
The advantage of using the normal time management for a single legal move is that scores
reported for that move are reasonable, not searching leads to artifacts during games
(see e.g. https://tcec-chess.com/#div=sf&game=96&season=19)
The disadvantage of using normal time management of a single legal move is that thinking
times can be unnaturally long, making it 'painful to watch' in online tournaments.
This patch uses normal time management, but caps the used time to 500ms.
This should lead to reasonable scores, and be hardly perceptible.
closes https://github.com/official-stockfish/Stockfish/pull/3195
closes https://github.com/official-stockfish/Stockfish/pull/3183
variant of a patch suggested by SFisGOD
No functional change.
2020-10-22 23:39:35 -06:00
|
|
|
// Cap used time in case of a single legal move for a better viewer experience in tournaments
|
|
|
|
// yielding correct scores and sufficiently fast moves.
|
|
|
|
if (rootMoves.size() == 1)
|
|
|
|
totalTime = std::min(500.0, totalTime);
|
|
|
|
|
|
|
|
// Stop the search if we have exceeded the totalTime
|
Minimal thinking time, even if only one rootMove.
without search, the eval returned can be misleading (e.g. mate instead of draw),
leading to wrong adjudication. With a minimal search, this is avoided.
This patch leads to 1ms long searches if there is only 1 move,
similar patches all indicate a small Elo gain.
Fixes https://github.com/official-stockfish/Stockfish/issues/2707
Passed non-regression STC:
LLR: 2.93 (-2.94,2.94) {-1.50,0.50}
Total: 22312 W: 4350 L: 4204 D: 13758
Ptnml(0-2): 323, 2488, 5437, 2536, 372
https://tests.stockfishchess.org/tests/view/5ed562b0f29b40b0fc95a7d0
closes https://github.com/official-stockfish/Stockfish/pull/2709
Bench: 4733799
2020-05-31 08:51:38 -06:00
|
|
|
if (Time.elapsed() > totalTime)
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
{
|
2019-01-01 06:10:26 -07:00
|
|
|
// If we are allowed to ponder do not stop the search now but
|
|
|
|
// keep pondering until the GUI sends "ponderhit" or "stop".
|
Simplify pondering time management (#1899)
stopOnPonderhit is used to stop search quickly on a ponderhit. It is set by mainThread as part of its time management. However, master employs it as a signal between mainThread and the UCI thread. This is not necessary, it is sufficient for the UCI thread to signal that pondering finished, and mainThread should do its usual time-keeping job, and in this case stop immediately.
This patch implements this, removing stopOnPonderHit as an atomic variable from the ThreadPool,
and moving it as a normal variable to mainThread, reducing its scope. In MainThread::check_time() the search is stopped immediately if ponder switches to false, and the variable stopOnPonderHit is set.
Furthermore, ponder has been moved to mainThread, as the variable is only used to exchange signals between the UCI thread and mainThread.
The version has been tested locally (as fishtest doesn't support ponder):
Score of ponderSimp vs master: 2616 - 2528 - 8630 [0.503] 13774
Elo difference: 2.22 +/- 3.54
which indicates no regression.
No functional change.
2019-01-20 11:14:24 -07:00
|
|
|
if (mainThread->ponder)
|
|
|
|
mainThread->stopOnPonderhit = true;
|
2019-01-01 06:10:26 -07:00
|
|
|
else
|
|
|
|
Threads.stop = true;
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
}
|
Smarter time management near stop limit
This patch makes Stockfish search same depth again if > 60% of optimum time is
already used, instead of trying the next iteration. The idea is that the next
iteration will generally take about the same amount of time as has already been
used in total. When we are likely to begin the last iteration, as judged by total
time taken so far > 0.6 * optimum time, searching the last depth again instead of
increasing the depth still helps the other threads in lazy SMP and prepares better
move ordering for the next moves.
STC :
LLR: 2.95 (-2.94,2.94) {-1.00,3.00}
Total: 13436 W: 2695 L: 2558 D: 8183
Ptnml(0-2): 222, 1538, 3087, 1611, 253
https://tests.stockfishchess.org/tests/view/5e1618a761fe5f83a67dd964
LTC :
LLR: 2.94 (-2.94,2.94) {0.00,2.00}
Total: 32160 W: 4261 L: 4047 D: 23852
Ptnml(0-2): 211, 2988, 9448, 3135, 247
https://tests.stockfishchess.org/tests/view/5e162ca061fe5f83a67dd96d
The code was revised as suggested by @vondele for multithreading:
STC (8 threads):
LLR: 2.95 (-2.94,2.94) {0.00,2.00}
Total: 16640 W: 2049 L: 1885 D: 12706
Ptnml(0-2): 119, 1369, 5158, 1557, 108
https://tests.stockfishchess.org/tests/view/5e19826a2cc590e03c3c2f52
LTC (8 threads):
LLR: 2.95 (-2.94,2.94) {-1.00,3.00}
Total: 16536 W: 2758 L: 2629 D: 11149
Ptnml(0-2): 182, 1758, 4296, 1802, 224
https://tests.stockfishchess.org/tests/view/5e18b91a27dab692fcf9a140
Thanks to those discussing Stockfish lazy SMP on fishcooking which made me
try this, and to @vondele for suggestions and doing related tests.
See full discussion in the pull request thread:
https://github.com/official-stockfish/Stockfish/pull/2482
Bench: 4586187
2020-01-11 15:10:22 -07:00
|
|
|
else if ( Threads.increaseDepth
|
2020-01-13 02:05:49 -07:00
|
|
|
&& !mainThread->ponder
|
Assorted search parameter tune
STC https://tests.stockfishchess.org/tests/view/5f31219090816720665374ec
LLR: 2.96 (-2.94,2.94) {-0.50,1.50}
Total: 3376 W: 487 L: 359 D: 2530
Ptnml(0-2): 17, 253, 1042, 337, 39
LTC https://tests.stockfishchess.org/tests/view/5f3127f79081672066537502
LLR: 2.93 (-2.94,2.94) {0.25,1.75}
Total: 8360 W: 581 L: 475 D: 7304
Ptnml(0-2): 11, 407, 3238, 513, 11
closes https://github.com/official-stockfish/Stockfish/pull/2971
bench: 4733874
2020-08-10 07:38:44 -06:00
|
|
|
&& Time.elapsed() > totalTime * 0.58)
|
Smarter time management near stop limit
This patch makes Stockfish search same depth again if > 60% of optimum time is
already used, instead of trying the next iteration. The idea is that the next
iteration will generally take about the same amount of time as has already been
used in total. When we are likely to begin the last iteration, as judged by total
time taken so far > 0.6 * optimum time, searching the last depth again instead of
increasing the depth still helps the other threads in lazy SMP and prepares better
move ordering for the next moves.
STC :
LLR: 2.95 (-2.94,2.94) {-1.00,3.00}
Total: 13436 W: 2695 L: 2558 D: 8183
Ptnml(0-2): 222, 1538, 3087, 1611, 253
https://tests.stockfishchess.org/tests/view/5e1618a761fe5f83a67dd964
LTC :
LLR: 2.94 (-2.94,2.94) {0.00,2.00}
Total: 32160 W: 4261 L: 4047 D: 23852
Ptnml(0-2): 211, 2988, 9448, 3135, 247
https://tests.stockfishchess.org/tests/view/5e162ca061fe5f83a67dd96d
The code was revised as suggested by @vondele for multithreading:
STC (8 threads):
LLR: 2.95 (-2.94,2.94) {0.00,2.00}
Total: 16640 W: 2049 L: 1885 D: 12706
Ptnml(0-2): 119, 1369, 5158, 1557, 108
https://tests.stockfishchess.org/tests/view/5e19826a2cc590e03c3c2f52
LTC (8 threads):
LLR: 2.95 (-2.94,2.94) {-1.00,3.00}
Total: 16536 W: 2758 L: 2629 D: 11149
Ptnml(0-2): 182, 1758, 4296, 1802, 224
https://tests.stockfishchess.org/tests/view/5e18b91a27dab692fcf9a140
Thanks to those discussing Stockfish lazy SMP on fishcooking which made me
try this, and to @vondele for suggestions and doing related tests.
See full discussion in the pull request thread:
https://github.com/official-stockfish/Stockfish/pull/2482
Bench: 4586187
2020-01-11 15:10:22 -07:00
|
|
|
Threads.increaseDepth = false;
|
|
|
|
else
|
|
|
|
Threads.increaseDepth = true;
|
2019-01-01 06:10:26 -07:00
|
|
|
}
|
2019-12-08 04:06:19 -07:00
|
|
|
|
|
|
|
mainThread->iterValue[iterIdx] = bestValue;
|
|
|
|
iterIdx = (iterIdx + 1) & 3;
|
2008-08-31 23:59:13 -06:00
|
|
|
}
|
|
|
|
|
2015-12-23 02:07:54 -07:00
|
|
|
if (!mainThread)
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
return;
|
|
|
|
|
Replace easyMove with simple scheme
Reduces time for a stable bestMove, giving some of the won time for the next move.
the version before the pvDraw passed both STC and LTC
passed STC:
http://tests.stockfishchess.org/tests/view/59e98d5a0ebc590ccbb896ec
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 78561 W: 13945 L: 13921 D: 50695
elo = 0.106 +- 1.445 LOS: 55.716%
passed LTC:
http://tests.stockfishchess.org/tests/view/59eb9df90ebc590ccbb897ae
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 29056 W: 3640 L: 3530 D: 21886
elo = 1.315 +- 1.982 LOS: 90.314%
This version, rebased on pvDrawPR with the obvious change, was verified again on STC:
http://tests.stockfishchess.org/tests/view/59ee104e0ebc590ccbb89899
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 19890 W: 3648 L: 3525 D: 12717
elo = 2.149 +- 2.895 LOS: 92.692%
and LTC:
http://tests.stockfishchess.org/tests/view/59f9673a0ebc590ccbb89ea0
Total : 17966
Win : 2273 ( 12.652%)
Loss : 2149 ( 11.961%)
Draw : 13544 ( 75.387%)
Score : 50.345%
Sensitivity : 0.014%
2*(W-L)/(W+L) : 5.608%
LLR [-3.0, 1.0] : 2.95
BayesElo range : [ -1.161, 4.876, 10.830] (DrawElo: 341.132)
LogisticElo range : [ -0.501, 2.105, 4.677]
LOS : 94.369 %
LTC again:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 17966 W: 2273 L: 2149 D: 13544
LogisticElo range : [ -0.501, 2.105, 4.677]
LOS : 94.369 %
unchanged bench: 5234652
2017-11-03 06:51:53 -06:00
|
|
|
mainThread->previousTimeReduction = timeReduction;
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
|
|
|
|
// If skill level is enabled, swap best PV line with the sub-optimal one
|
|
|
|
if (skill.enabled())
|
2017-10-10 23:49:58 -06:00
|
|
|
std::swap(rootMoves[0], *std::find(rootMoves.begin(), rootMoves.end(),
|
|
|
|
skill.best ? skill.best : skill.pick_best(multiPV)));
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
namespace {
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2015-10-25 05:07:22 -06:00
|
|
|
// search<>() is the main search function for both PV and non-PV nodes
|
2008-08-31 23:59:13 -06:00
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
template <NodeType NT>
|
2018-05-08 02:43:46 -06:00
|
|
|
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode) {
|
2010-05-08 02:54:51 -06:00
|
|
|
|
Renaming some variables in code
Implements renaming suggestions by Marco Costalba, Günther Demetz,
Gontran Lemaire, Ronald de Man, Stéphane Nicolet, Alain Savard,
Joost VandeVondele, Jerry Donald Watson, Mike Whiteley, xoto10,
and I hope that I haven't forgotten anybody.
Perpetual renaming thread for suggestions:
https://github.com/official-stockfish/Stockfish/issues/1426
No functional change.
2018-03-15 03:44:26 -06:00
|
|
|
constexpr bool PvNode = NT == PV;
|
Let ss->ply denote the number of plies from the root to the current node
This patch lets ss->ply be equal to 0 at the root of the search.
Currently, the root has ss->ply == 1, which is less intuitive:
- Setting the rootNode bool has to check (ss-1)->ply == 0.
- All mate values are off by one: the code seems to assume that mated-in-0
is -VALUE_MATE, mate-1-in-ply is VALUE_MATE-1, mated-in-2-ply is VALUE_MATE+2, etc.
But the mate_in() and mated_in() functions are called with ss->ply, which is 1 in
at the root.
- The is_draw() function currently needs to explain why it has "ply - 1 > i" instead
of simply "ply > i".
- The ss->ply >= MAX_PLY tests in search() and qsearch() already assume that
ss->ply == 0 at the root. If we start at ss->ply == 1, it would make more sense to
go up to and including ss->ply == MAX_PLY, so stop at ss->ply > MAX_PLY. See also
the asserts testing for 0 <= ss->ply && ss->ply < MAX_PLY.
The reason for ss->ply == 1 at the root is the line "ss->ply = (ss-1)->ply + 1" at
the start for search() and qsearch(). By replacing this with "(ss+1)->ply = ss->ply + 1"
we keep ss->ply == 0 at the root. Note that search() already clears killers in (ss+2),
so there is no danger in accessing ss+1.
I have NOT changed pv[MAX_PLY + 1] to pv[MAX_PLY + 2] in search() and qsearch().
It seems to me that MAX_PLY + 1 is exactly right:
- MAX_PLY entries for ss->ply running from 0 to MAX_PLY-1, and 1 entry for the
final MOVE_NONE.
I have verified that mate scores are reported correctly. (They were already reported
correctly due to the extra ply being rounded down when converting to moves.)
The value of seldepth output to the user should probably not change, so I add 1 to it.
(Humans count from 1, computers from 0.)
A small optimisation I did not include: instead of setting ss->ply in every invocation
of search() and qsearch(), it could be set once for all plies at the start of
Thread::search(). This saves a couple of instructions per node.
No functional change (unless the search searches a branch MAX_PLY deep), so bench
does not change.
2017-09-16 13:49:29 -06:00
|
|
|
const bool rootNode = PvNode && ss->ply == 0;
|
Reduce big time spikes by reducing PV re-searches.
Save time by reducing PV re-searches above original depth. Instead use 5% extra time on every move.
STC 10+0.1 th 1 :
LLR: 2.93 (-2.94,2.94) {-0.25,1.25}
Total: 90688 W: 9702 L: 9436 D: 71550
Ptnml(0-2): 408, 7252, 29792, 7450, 442
https://tests.stockfishchess.org/tests/view/5f8df807bacb75a4f9a47223
LTC 60+0.6 th 1 :
LLR: 2.97 (-2.94,2.94) {0.25,1.25}
Total: 97856 W: 4602 L: 4303 D: 88951
Ptnml(0-2): 53, 3757, 41057, 3960, 101
https://tests.stockfishchess.org/tests/view/5f8ec4872c92c7fe3a8c602d
closes https://github.com/official-stockfish/Stockfish/pull/3192
Bench 3943959
2020-10-21 07:52:13 -06:00
|
|
|
const Depth maxNextDepth = rootNode ? depth : depth + 1;
|
2011-05-28 05:13:42 -06:00
|
|
|
|
2018-06-11 01:46:05 -06:00
|
|
|
// Check if we have an upcoming move which draws by repetition, or
|
2018-06-05 02:54:51 -06:00
|
|
|
// if the opponent had an alternative move earlier to this position.
|
|
|
|
if ( pos.rule50_count() >= 3
|
|
|
|
&& alpha < VALUE_DRAW
|
|
|
|
&& !rootNode
|
|
|
|
&& pos.has_game_cycle(ss->ply))
|
|
|
|
{
|
2019-09-27 11:25:22 -06:00
|
|
|
alpha = value_draw(pos.this_thread());
|
2018-06-05 02:54:51 -06:00
|
|
|
if (alpha >= beta)
|
|
|
|
return alpha;
|
|
|
|
}
|
|
|
|
|
|
|
|
// Dive into quiescence search when the depth reaches zero
|
2019-09-28 14:27:23 -06:00
|
|
|
if (depth <= 0)
|
2018-06-05 02:54:51 -06:00
|
|
|
return qsearch<NT>(pos, ss, alpha, beta);
|
|
|
|
|
2014-02-15 01:20:27 -07:00
|
|
|
assert(-VALUE_INFINITE <= alpha && alpha < beta && beta <= VALUE_INFINITE);
|
2012-09-29 10:26:17 -06:00
|
|
|
assert(PvNode || (alpha == beta - 1));
|
2019-09-28 14:27:23 -06:00
|
|
|
assert(0 < depth && depth < MAX_PLY);
|
2016-06-23 08:14:51 -06:00
|
|
|
assert(!(PvNode && cutNode));
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2017-11-03 05:37:11 -06:00
|
|
|
Move pv[MAX_PLY+1], capturesSearched[32], quietsSearched[64];
|
2009-11-05 03:11:02 -07:00
|
|
|
StateInfo st;
|
2021-04-19 11:50:19 -06:00
|
|
|
ASSERT_ALIGNED(&st, Eval::NNUE::CacheLineSize);
|
2020-11-03 03:23:35 -07:00
|
|
|
|
2014-12-13 00:16:35 -07:00
|
|
|
TTEntry* tte;
|
2010-06-02 06:22:48 -06:00
|
|
|
Key posKey;
|
2013-12-14 04:27:29 -07:00
|
|
|
Move ttMove, move, excludedMove, bestMove;
|
2016-09-14 07:09:41 -06:00
|
|
|
Depth extension, newDepth;
|
2020-07-18 07:30:00 -06:00
|
|
|
Value bestValue, value, ttValue, eval, maxValue, probCutBeta;
|
Adjust penalty on refuted early quiet moves
This patch changes how previous early moves are penalized in case
search finds a best move. Here, the first quiet move that was not
a transposition table move is penalized.
passed STC
https://tests.stockfishchess.org/tests/view/5f51d839ba100690c5cc5f69
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 10088 W: 1150 L: 997 D: 7941
Ptnml(0-2): 41, 772, 3278, 899, 54
passed LTC
https://tests.stockfishchess.org/tests/view/5f51e435ba100690c5cc5f76
LLR: 2.93 (-2.94,2.94) {0.25,1.25}
Total: 30808 W: 1564 L: 1405 D: 27839
Ptnml(0-2): 19, 1245, 12717, 1404, 19
closes https://github.com/official-stockfish/Stockfish/pull/3106
bench 3983758
2020-09-04 06:53:59 -06:00
|
|
|
bool formerPv, givesCheck, improving, didLMR, priorCapture;
|
Singular quiet LMR
If ttMove is a capture and had a singular extension, it is probably the best move.
No need to make a decrease of LMR on other moves.
STC
LLR: 2.96 (-2.94,2.94) {-0.50,1.50}
Total: 41968 W: 8170 L: 7918 D: 25880
Ptnml(0-2): 733, 4770, 9726, 5022, 733
https://tests.stockfishchess.org/tests/view/5ed6b666f29b40b0fc95a884
LTC
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 71376 W: 9200 L: 8827 D: 53349
Ptnml(0-2): 486, 6544, 21342, 6743, 573
https://tests.stockfishchess.org/tests/view/5ed7578bf29b40b0fc95a8c9
closes https://github.com/official-stockfish/Stockfish/pull/2713
Bench: 4733799
2020-06-02 14:27:11 -06:00
|
|
|
bool captureOrPromotion, doFullDepthSearch, moveCountPruning,
|
|
|
|
ttCapture, singularQuietLMR;
|
2019-10-06 01:57:20 -06:00
|
|
|
Piece movedPiece;
|
2019-10-21 14:21:50 -06:00
|
|
|
int moveCount, captureCount, quietCount;
|
2011-01-16 04:02:32 -07:00
|
|
|
|
2012-10-01 01:33:13 -06:00
|
|
|
// Step 1. Initialize node
|
2012-09-29 10:26:17 -06:00
|
|
|
Thread* thisThread = pos.this_thread();
|
2021-03-19 12:43:25 -06:00
|
|
|
ss->inCheck = pos.checkers();
|
|
|
|
priorCapture = pos.captured_piece();
|
|
|
|
Color us = pos.side_to_move();
|
|
|
|
moveCount = captureCount = quietCount = ss->moveCount = 0;
|
|
|
|
bestValue = -VALUE_INFINITE;
|
|
|
|
maxValue = VALUE_INFINITE;
|
2012-10-01 01:33:13 -06:00
|
|
|
|
2016-01-16 14:34:29 -07:00
|
|
|
// Check for the available remaining time
|
2017-06-23 23:15:46 -06:00
|
|
|
if (thisThread == Threads.main())
|
|
|
|
static_cast<MainThread*>(thisThread)->check_time();
|
Get rid of timer thread
Unfortunately std::condition_variable::wait_for()
is not accurate in general case and the timer thread
can wake up also after tens or even hundreds of
millisecs after time has elapsded. CPU load, process
priorities, number of concurrent threads, even from
other processes, will have effect upon it.
Even official documentation says: "This function may
block for longer than timeout_duration due to scheduling
or resource contention delays."
So retire timer and use a polling scheme based on a
local thread counter that counts search() calls and
a small trick to keep polling frequency constant,
independently from the number of threads.
Tested for no regression at very fast TC 2+0.05 th 7:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 32969 W: 6720 L: 6620 D: 19629
TC 2+0.05 th 1:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 7765 W: 1917 L: 1765 D: 4083
And at STC TC, both single thread
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 15587 W: 3036 L: 2905 D: 9646
And with 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 8149 W: 1367 L: 1227 D: 5555
bench: 8639247
2015-11-03 03:15:14 -07:00
|
|
|
|
Let ss->ply denote the number of plies from the root to the current node
This patch lets ss->ply be equal to 0 at the root of the search.
Currently, the root has ss->ply == 1, which is less intuitive:
- Setting the rootNode bool has to check (ss-1)->ply == 0.
- All mate values are off by one: the code seems to assume that mated-in-0
is -VALUE_MATE, mate-1-in-ply is VALUE_MATE-1, mated-in-2-ply is VALUE_MATE+2, etc.
But the mate_in() and mated_in() functions are called with ss->ply, which is 1 in
at the root.
- The is_draw() function currently needs to explain why it has "ply - 1 > i" instead
of simply "ply > i".
- The ss->ply >= MAX_PLY tests in search() and qsearch() already assume that
ss->ply == 0 at the root. If we start at ss->ply == 1, it would make more sense to
go up to and including ss->ply == MAX_PLY, so stop at ss->ply > MAX_PLY. See also
the asserts testing for 0 <= ss->ply && ss->ply < MAX_PLY.
The reason for ss->ply == 1 at the root is the line "ss->ply = (ss-1)->ply + 1" at
the start for search() and qsearch(). By replacing this with "(ss+1)->ply = ss->ply + 1"
we keep ss->ply == 0 at the root. Note that search() already clears killers in (ss+2),
so there is no danger in accessing ss+1.
I have NOT changed pv[MAX_PLY + 1] to pv[MAX_PLY + 2] in search() and qsearch().
It seems to me that MAX_PLY + 1 is exactly right:
- MAX_PLY entries for ss->ply running from 0 to MAX_PLY-1, and 1 entry for the
final MOVE_NONE.
I have verified that mate scores are reported correctly. (They were already reported
correctly due to the extra ply being rounded down when converting to moves.)
The value of seldepth output to the user should probably not change, so I add 1 to it.
(Humans count from 1, computers from 0.)
A small optimisation I did not include: instead of setting ss->ply in every invocation
of search() and qsearch(), it could be set once for all plies at the start of
Thread::search(). This saves a couple of instructions per node.
No functional change (unless the search searches a branch MAX_PLY deep), so bench
does not change.
2017-09-16 13:49:29 -06:00
|
|
|
// Used to send selDepth info to GUI (selDepth counts from 1, ply from 0)
|
|
|
|
if (PvNode && thisThread->selDepth < ss->ply + 1)
|
|
|
|
thisThread->selDepth = ss->ply + 1;
|
2009-11-05 03:11:02 -07:00
|
|
|
|
2016-01-18 15:20:16 -07:00
|
|
|
if (!rootNode)
|
2011-06-18 10:10:29 -06:00
|
|
|
{
|
2012-09-29 10:26:17 -06:00
|
|
|
// Step 2. Check for aborted search and immediate draw
|
2018-02-12 14:57:42 -07:00
|
|
|
if ( Threads.stop.load(std::memory_order_relaxed)
|
|
|
|
|| pos.is_draw(ss->ply)
|
|
|
|
|| ss->ply >= MAX_PLY)
|
continuation histories when in check
If in check, don't write to continuation histories ss-4, ss-6.
Adding inCheck to the stack was needed, and might be useful for
future patches.
Passed STC:
https://tests.stockfishchess.org/tests/view/5e9ee24acaaff5d60a50b812
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 61774 W: 11725 L: 11449 D: 38600
Ptnml(0-2): 971, 7211, 14322, 7337, 1046
Passed LTC:
https://tests.stockfishchess.org/tests/view/5e9eecb7caaff5d60a50b831
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 250822 W: 32067 L: 31179 D: 187576
Ptnml(0-2): 1745, 23126, 74824, 23928, 1788
closes https://github.com/official-stockfish/Stockfish/pull/2645
bench: 4808463
2020-04-21 12:55:41 -06:00
|
|
|
return (ss->ply >= MAX_PLY && !ss->inCheck) ? evaluate(pos)
|
2020-06-24 14:19:58 -06:00
|
|
|
: value_draw(pos.this_thread());
|
2012-09-29 10:26:17 -06:00
|
|
|
|
|
|
|
// Step 3. Mate distance pruning. Even if we mate at the next move our score
|
|
|
|
// would be at best mate_in(ss->ply+1), but if alpha is already bigger because
|
|
|
|
// a shorter mate was found upward in the tree then there is no need to search
|
2013-12-02 11:04:09 -07:00
|
|
|
// because we will never beat the current alpha. Same logic but with reversed
|
|
|
|
// signs applies also in the opposite condition of being mated instead of giving
|
|
|
|
// mate. In this case return a fail-high score.
|
2011-12-27 08:01:33 -07:00
|
|
|
alpha = std::max(mated_in(ss->ply), alpha);
|
|
|
|
beta = std::min(mate_in(ss->ply+1), beta);
|
2011-06-18 10:10:29 -06:00
|
|
|
if (alpha >= beta)
|
|
|
|
return alpha;
|
|
|
|
}
|
2010-02-24 03:19:47 -07:00
|
|
|
|
Cleanup MAX_PLY
This area has become obscure and tricky over the course of incremental
changes that did not respect the original's consistency and clarity. Now,
it's not clear why we use MAX_PLY = 120, or why we use MAX_PLY+6, among
other things.
This patch does the following:
* ID loop: depth ranges from 1 to MAX_PLY-1, and due to TT constraint (depth
must fit into an int8_t), MAX_PLY should be 128.
* stack[]: plies now range from 0 to MAX_PLY-1, hence stack[MAX_PLY+4],
because of the extra 2+2 padding elements (for ss-2 and ss+2). Document this
better, while we're at it.
* Enforce 0 <= ply < MAX_PLY:
- stop condition is now ss->ply >= MAX_PLY and not ss->ply > MAX_PLY.
- assert(ss->ply < MAX_PLY), before using ss+1 and ss+2.
- as a result, we don't need the artificial MAX_PLY+6 range. Instead we
can use MAX_PLY+4 and it's clear why (for ss-2 and ss+2).
* fix: extract_pv_from_tt() and insert_pv_in_tt() had no reason to use
MAX_PLY_PLUS_6, because the array is indexed by plies, so the range of
available plies applies (0..MAX_PLY before, and now 0..MAX_PLY-1).
Tested with debug compile, using MAX_PLY=16, and running bench at depth 17,
using 1 and 7 threads. No assert() fired. Feel free to submit to more severe
crash-tests, if you can think of any.
No functional change.
2014-11-03 08:36:24 -07:00
|
|
|
assert(0 <= ss->ply && ss->ply < MAX_PLY);
|
|
|
|
|
Let ss->ply denote the number of plies from the root to the current node
This patch lets ss->ply be equal to 0 at the root of the search.
Currently, the root has ss->ply == 1, which is less intuitive:
- Setting the rootNode bool has to check (ss-1)->ply == 0.
- All mate values are off by one: the code seems to assume that mated-in-0
is -VALUE_MATE, mate-1-in-ply is VALUE_MATE-1, mated-in-2-ply is VALUE_MATE+2, etc.
But the mate_in() and mated_in() functions are called with ss->ply, which is 1 in
at the root.
- The is_draw() function currently needs to explain why it has "ply - 1 > i" instead
of simply "ply > i".
- The ss->ply >= MAX_PLY tests in search() and qsearch() already assume that
ss->ply == 0 at the root. If we start at ss->ply == 1, it would make more sense to
go up to and including ss->ply == MAX_PLY, so stop at ss->ply > MAX_PLY. See also
the asserts testing for 0 <= ss->ply && ss->ply < MAX_PLY.
The reason for ss->ply == 1 at the root is the line "ss->ply = (ss-1)->ply + 1" at
the start for search() and qsearch(). By replacing this with "(ss+1)->ply = ss->ply + 1"
we keep ss->ply == 0 at the root. Note that search() already clears killers in (ss+2),
so there is no danger in accessing ss+1.
I have NOT changed pv[MAX_PLY + 1] to pv[MAX_PLY + 2] in search() and qsearch().
It seems to me that MAX_PLY + 1 is exactly right:
- MAX_PLY entries for ss->ply running from 0 to MAX_PLY-1, and 1 entry for the
final MOVE_NONE.
I have verified that mate scores are reported correctly. (They were already reported
correctly due to the extra ply being rounded down when converting to moves.)
The value of seldepth output to the user should probably not change, so I add 1 to it.
(Humans count from 1, computers from 0.)
A small optimisation I did not include: instead of setting ss->ply in every invocation
of search() and qsearch(), it could be set once for all plies at the start of
Thread::search(). This saves a couple of instructions per node.
No functional change (unless the search searches a branch MAX_PLY deep), so bench
does not change.
2017-09-16 13:49:29 -06:00
|
|
|
(ss+1)->ply = ss->ply + 1;
|
Add / remove leaves from search tree ttPv
add if previous leaf is in search tree and we didn't find a counter move
else remove the position if the leaf is the last one in search tree.
STC : https://tests.stockfishchess.org/tests/view/5f49203c3def640786115314
LLR: 2.95 (-2.94,2.94) {-0.25,1.25}
Total: 29968 W: 3381 L: 3195 D: 23392
Ptnml(0-2): 146, 2432, 9671, 2560, 175
LTC : https://tests.stockfishchess.org/tests/view/5f494bea3def640786115336
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 84952 W: 4619 L: 4333 D: 76000
Ptnml(0-2): 86, 3765, 34481, 4065, 79
closes https://github.com/official-stockfish/Stockfish/pull/3075
Bench 3527337
2020-08-28 04:06:36 -06:00
|
|
|
(ss+1)->ttPv = false;
|
2019-04-24 11:51:57 -06:00
|
|
|
(ss+1)->excludedMove = bestMove = MOVE_NONE;
|
Cleanup MAX_PLY
This area has become obscure and tricky over the course of incremental
changes that did not respect the original's consistency and clarity. Now,
it's not clear why we use MAX_PLY = 120, or why we use MAX_PLY+6, among
other things.
This patch does the following:
* ID loop: depth ranges from 1 to MAX_PLY-1, and due to TT constraint (depth
must fit into an int8_t), MAX_PLY should be 128.
* stack[]: plies now range from 0 to MAX_PLY-1, hence stack[MAX_PLY+4],
because of the extra 2+2 padding elements (for ss-2 and ss+2). Document this
better, while we're at it.
* Enforce 0 <= ply < MAX_PLY:
- stop condition is now ss->ply >= MAX_PLY and not ss->ply > MAX_PLY.
- assert(ss->ply < MAX_PLY), before using ss+1 and ss+2.
- as a result, we don't need the artificial MAX_PLY+6 range. Instead we
can use MAX_PLY+4 and it's clear why (for ss-2 and ss+2).
* fix: extract_pv_from_tt() and insert_pv_in_tt() had no reason to use
MAX_PLY_PLUS_6, because the array is indexed by plies, so the range of
available plies applies (0..MAX_PLY before, and now 0..MAX_PLY-1).
Tested with debug compile, using MAX_PLY=16, and running bench at depth 17,
using 1 and 7 threads. No assert() fired. Feel free to submit to more severe
crash-tests, if you can think of any.
No functional change.
2014-11-03 08:36:24 -07:00
|
|
|
(ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
|
2016-12-05 10:58:12 -07:00
|
|
|
Square prevSq = to_sq((ss-1)->currentMove);
|
Cleanup MAX_PLY
This area has become obscure and tricky over the course of incremental
changes that did not respect the original's consistency and clarity. Now,
it's not clear why we use MAX_PLY = 120, or why we use MAX_PLY+6, among
other things.
This patch does the following:
* ID loop: depth ranges from 1 to MAX_PLY-1, and due to TT constraint (depth
must fit into an int8_t), MAX_PLY should be 128.
* stack[]: plies now range from 0 to MAX_PLY-1, hence stack[MAX_PLY+4],
because of the extra 2+2 padding elements (for ss-2 and ss+2). Document this
better, while we're at it.
* Enforce 0 <= ply < MAX_PLY:
- stop condition is now ss->ply >= MAX_PLY and not ss->ply > MAX_PLY.
- assert(ss->ply < MAX_PLY), before using ss+1 and ss+2.
- as a result, we don't need the artificial MAX_PLY+6 range. Instead we
can use MAX_PLY+4 and it's clear why (for ss-2 and ss+2).
* fix: extract_pv_from_tt() and insert_pv_in_tt() had no reason to use
MAX_PLY_PLUS_6, because the array is indexed by plies, so the range of
available plies applies (0..MAX_PLY before, and now 0..MAX_PLY-1).
Tested with debug compile, using MAX_PLY=16, and running bench at depth 17,
using 1 and 7 threads. No assert() fired. Feel free to submit to more severe
crash-tests, if you can think of any.
No functional change.
2014-11-03 08:36:24 -07:00
|
|
|
|
2018-02-27 10:38:08 -07:00
|
|
|
// Initialize statScore to zero for the grandchildren of the current position.
|
|
|
|
// So statScore is shared between all grandchildren and only the first grandchild
|
|
|
|
// starts with statScore = 0. Later grandchildren start with the last calculated
|
|
|
|
// statScore of the previous grandchild. This influences the reduction rules in
|
|
|
|
// LMR which are based on the statScore of parent position.
|
2020-09-13 20:28:32 -06:00
|
|
|
if (!rootNode)
|
2019-08-14 14:15:41 -06:00
|
|
|
(ss+2)->statScore = 0;
|
2018-02-27 10:38:08 -07:00
|
|
|
|
2015-10-23 23:27:24 -06:00
|
|
|
// Step 4. Transposition table lookup. We don't want the score of a partial
|
|
|
|
// search to overwrite a previous full search TT value, so we use a different
|
|
|
|
// position key in case of an excluded move.
|
2013-11-18 23:19:28 -07:00
|
|
|
excludedMove = ss->excludedMove;
|
Fix fragile code to use proper random 64 bit keys.
This fixes an old issue where we want to make a position unique but only
change a small number of bits in the key instead of all 64 of them randomly.
This is fragile and can lead to non uniqueness issues in the TT.
Key make_key(uint64_t seed) takes any integer and produces a unique random 64 bit key.
It is computationally efficient and is based on a congruential pseudo random number
generator using well tested constants by Donald Knuth
(see https://en.wikipedia.org/wiki/Linear_congruential_generator)
STC https://tests.stockfishchess.org/tests/view/5ef6c78f761b685b4c724bb6
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 154320 W: 29343 L: 29376 D: 95601
Ptnml(0-2): 2543, 18170, 35891, 17889, 2667
LTC https://tests.stockfishchess.org/tests/view/5ef7d1a9020eec13834a940e
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 53488 W: 6629 L: 6584 D: 40275
Ptnml(0-2): 372, 4878, 16183, 4955, 356
closes https://github.com/official-stockfish/Stockfish/pull/2773
bench: 4626776
2020-06-26 18:26:46 -06:00
|
|
|
posKey = excludedMove == MOVE_NONE ? pos.key() : pos.key() ^ make_key(excludedMove);
|
Adjust penalty on refuted early quiet moves
This patch changes how previous early moves are penalized in case
search finds a best move. Here, the first quiet move that was not
a transposition table move is penalized.
passed STC
https://tests.stockfishchess.org/tests/view/5f51d839ba100690c5cc5f69
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 10088 W: 1150 L: 997 D: 7941
Ptnml(0-2): 41, 772, 3278, 899, 54
passed LTC
https://tests.stockfishchess.org/tests/view/5f51e435ba100690c5cc5f76
LLR: 2.93 (-2.94,2.94) {0.25,1.25}
Total: 30808 W: 1564 L: 1405 D: 27839
Ptnml(0-2): 19, 1245, 12717, 1404, 19
closes https://github.com/official-stockfish/Stockfish/pull/3106
bench 3983758
2020-09-04 06:53:59 -06:00
|
|
|
tte = TT.probe(posKey, ss->ttHit);
|
|
|
|
ttValue = ss->ttHit ? value_from_tt(tte->value(), ss->ply, pos.rule50_count()) : VALUE_NONE;
|
2018-06-02 09:41:37 -06:00
|
|
|
ttMove = rootNode ? thisThread->rootMoves[thisThread->pvIdx].pv[0]
|
Adjust penalty on refuted early quiet moves
This patch changes how previous early moves are penalized in case
search finds a best move. Here, the first quiet move that was not
a transposition table move is penalized.
passed STC
https://tests.stockfishchess.org/tests/view/5f51d839ba100690c5cc5f69
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 10088 W: 1150 L: 997 D: 7941
Ptnml(0-2): 41, 772, 3278, 899, 54
passed LTC
https://tests.stockfishchess.org/tests/view/5f51e435ba100690c5cc5f76
LLR: 2.93 (-2.94,2.94) {0.25,1.25}
Total: 30808 W: 1564 L: 1405 D: 27839
Ptnml(0-2): 19, 1245, 12717, 1404, 19
closes https://github.com/official-stockfish/Stockfish/pull/3106
bench 3983758
2020-09-04 06:53:59 -06:00
|
|
|
: ss->ttHit ? tte->move() : MOVE_NONE;
|
Add / remove leaves from search tree ttPv
add if previous leaf is in search tree and we didn't find a counter move
else remove the position if the leaf is the last one in search tree.
STC : https://tests.stockfishchess.org/tests/view/5f49203c3def640786115314
LLR: 2.95 (-2.94,2.94) {-0.25,1.25}
Total: 29968 W: 3381 L: 3195 D: 23392
Ptnml(0-2): 146, 2432, 9671, 2560, 175
LTC : https://tests.stockfishchess.org/tests/view/5f494bea3def640786115336
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 84952 W: 4619 L: 4333 D: 76000
Ptnml(0-2): 86, 3765, 34481, 4065, 79
closes https://github.com/official-stockfish/Stockfish/pull/3075
Bench 3527337
2020-08-28 04:06:36 -06:00
|
|
|
if (!excludedMove)
|
Adjust penalty on refuted early quiet moves
This patch changes how previous early moves are penalized in case
search finds a best move. Here, the first quiet move that was not
a transposition table move is penalized.
passed STC
https://tests.stockfishchess.org/tests/view/5f51d839ba100690c5cc5f69
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 10088 W: 1150 L: 997 D: 7941
Ptnml(0-2): 41, 772, 3278, 899, 54
passed LTC
https://tests.stockfishchess.org/tests/view/5f51e435ba100690c5cc5f76
LLR: 2.93 (-2.94,2.94) {0.25,1.25}
Total: 30808 W: 1564 L: 1405 D: 27839
Ptnml(0-2): 19, 1245, 12717, 1404, 19
closes https://github.com/official-stockfish/Stockfish/pull/3106
bench 3983758
2020-09-04 06:53:59 -06:00
|
|
|
ss->ttPv = PvNode || (ss->ttHit && tte->is_pv());
|
Add / remove leaves from search tree ttPv
add if previous leaf is in search tree and we didn't find a counter move
else remove the position if the leaf is the last one in search tree.
STC : https://tests.stockfishchess.org/tests/view/5f49203c3def640786115314
LLR: 2.95 (-2.94,2.94) {-0.25,1.25}
Total: 29968 W: 3381 L: 3195 D: 23392
Ptnml(0-2): 146, 2432, 9671, 2560, 175
LTC : https://tests.stockfishchess.org/tests/view/5f494bea3def640786115336
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 84952 W: 4619 L: 4333 D: 76000
Ptnml(0-2): 86, 3765, 34481, 4065, 79
closes https://github.com/official-stockfish/Stockfish/pull/3075
Bench 3527337
2020-08-28 04:06:36 -06:00
|
|
|
formerPv = ss->ttPv && !PvNode;
|
Improve move order near the root
Current move histories are known to work well near the leaves, whilst at
higher depths they aren't very helpful. To address this problem this
patch introduces a table dedicated for what's happening at plies 0-3.
It's structured like mainHistory with ply index instead of color.
It get cleared with each new search and is filled during iterative
deepening at higher depths when recording successful quiet moves near
the root or traversing nodes which were in the principal variation
(ttPv).
Medium TC (20+0.2):
https://tests.stockfishchess.org/tests/view/5e4d358790a0a02810d096dc
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 100910 W: 16682 L: 16376 D: 67852
Ptnml(0-2): 1177, 10983, 25883, 11181, 1231
LTC:
https://tests.stockfishchess.org/tests/view/5e4e2cb790a0a02810d09714
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 80444 W: 10495 L: 10095 D: 59854
Ptnml(0-2): 551, 7479, 23803, 7797, 592
closes https://github.com/official-stockfish/Stockfish/pull/2557
Bench: 4705960
2020-02-21 06:01:59 -07:00
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// Update low ply history for previous move if we are near root and position is or has been in PV
|
Add / remove leaves from search tree ttPv
add if previous leaf is in search tree and we didn't find a counter move
else remove the position if the leaf is the last one in search tree.
STC : https://tests.stockfishchess.org/tests/view/5f49203c3def640786115314
LLR: 2.95 (-2.94,2.94) {-0.25,1.25}
Total: 29968 W: 3381 L: 3195 D: 23392
Ptnml(0-2): 146, 2432, 9671, 2560, 175
LTC : https://tests.stockfishchess.org/tests/view/5f494bea3def640786115336
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 84952 W: 4619 L: 4333 D: 76000
Ptnml(0-2): 86, 3765, 34481, 4065, 79
closes https://github.com/official-stockfish/Stockfish/pull/3075
Bench 3527337
2020-08-28 04:06:36 -06:00
|
|
|
if ( ss->ttPv
|
2020-07-09 14:01:06 -06:00
|
|
|
&& depth > 12
|
|
|
|
&& ss->ply - 1 < MAX_LPH
|
|
|
|
&& !priorCapture
|
|
|
|
&& is_ok((ss-1)->currentMove))
|
Improve move order near the root
Current move histories are known to work well near the leaves, whilst at
higher depths they aren't very helpful. To address this problem this
patch introduces a table dedicated for what's happening at plies 0-3.
It's structured like mainHistory with ply index instead of color.
It get cleared with each new search and is filled during iterative
deepening at higher depths when recording successful quiet moves near
the root or traversing nodes which were in the principal variation
(ttPv).
Medium TC (20+0.2):
https://tests.stockfishchess.org/tests/view/5e4d358790a0a02810d096dc
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 100910 W: 16682 L: 16376 D: 67852
Ptnml(0-2): 1177, 10983, 25883, 11181, 1231
LTC:
https://tests.stockfishchess.org/tests/view/5e4e2cb790a0a02810d09714
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 80444 W: 10495 L: 10095 D: 59854
Ptnml(0-2): 551, 7479, 23803, 7797, 592
closes https://github.com/official-stockfish/Stockfish/pull/2557
Bench: 4705960
2020-02-21 06:01:59 -07:00
|
|
|
thisThread->lowPlyHistory[ss->ply - 1][from_to((ss-1)->currentMove)] << stat_bonus(depth - 5);
|
|
|
|
|
Use exploration rate for reductions
This patch measures how frequently search is exploring new configurations.
This is done be computing a running average of ttHit. The ttHitAverage rate
is somewhat low (e.g. 30% for startpos) in the normal case, while it can be
very high if no progress is made (e.g. 90% for the fortress I used for testing).
This information can be used to influence search. In this patch, by adjusting
reductions if the rate > 50%. A first version (using a low ttHitAverageResolution
and this 50% threshold) passed testing:
STC
LLR: 2.96 (-2.94,2.94) [-1.50,4.50]
Total: 26425 W: 5837 L: 5650 D: 14938
http://tests.stockfishchess.org/tests/view/5dcede8b0ebc5902563258fa
LTC
LLR: 2.96 (-2.94,2.94) [0.00,3.50]
Total: 32313 W: 5392 L: 5128 D: 21793
http://tests.stockfishchess.org/tests/view/5dcefb1f0ebc590256325c0e
However, as discussed in pull request 2414, using a larger ttHitAverageResolution
gives a better approximation of the underlying distributions. This needs a slight
adjustment for the threshold as the new distributions are shifted a bit compared
to the older ones, and this threshold seemingly is sensitive (we used 0.53125 here).
https://github.com/official-stockfish/Stockfish/pull/2414
This final version also passed testing, and is used for the patch:
STC
LLR: 2.95 (-2.94,2.94) [-1.50,4.50]
Total: 16025 W: 3555 L: 3399 D: 9071
http://tests.stockfishchess.org/tests/view/5dd070b90ebc5902579e20c2
LTC
LLR: 2.96 (-2.94,2.94) [0.00,3.50]
Total: 37576 W: 6277 L: 5998 D: 25301
http://tests.stockfishchess.org/tests/view/5dd0f58e6f544e798086f224
Closes https://github.com/official-stockfish/Stockfish/pull/2414
Bench: 4989584
2019-11-15 10:16:27 -07:00
|
|
|
// thisThread->ttHitAverage can be used to approximate the running average of ttHit
|
2020-04-29 09:39:25 -06:00
|
|
|
thisThread->ttHitAverage = (TtHitAverageWindow - 1) * thisThread->ttHitAverage / TtHitAverageWindow
|
Adjust penalty on refuted early quiet moves
This patch changes how previous early moves are penalized in case
search finds a best move. Here, the first quiet move that was not
a transposition table move is penalized.
passed STC
https://tests.stockfishchess.org/tests/view/5f51d839ba100690c5cc5f69
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 10088 W: 1150 L: 997 D: 7941
Ptnml(0-2): 41, 772, 3278, 899, 54
passed LTC
https://tests.stockfishchess.org/tests/view/5f51e435ba100690c5cc5f76
LLR: 2.93 (-2.94,2.94) {0.25,1.25}
Total: 30808 W: 1564 L: 1405 D: 27839
Ptnml(0-2): 19, 1245, 12717, 1404, 19
closes https://github.com/official-stockfish/Stockfish/pull/3106
bench 3983758
2020-09-04 06:53:59 -06:00
|
|
|
+ TtHitAverageResolution * ss->ttHit;
|
2008-09-06 07:53:43 -06:00
|
|
|
|
2015-10-23 23:27:24 -06:00
|
|
|
// At non-PV nodes we check for an early TT cutoff
|
2014-11-18 03:57:57 -07:00
|
|
|
if ( !PvNode
|
Adjust penalty on refuted early quiet moves
This patch changes how previous early moves are penalized in case
search finds a best move. Here, the first quiet move that was not
a transposition table move is penalized.
passed STC
https://tests.stockfishchess.org/tests/view/5f51d839ba100690c5cc5f69
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 10088 W: 1150 L: 997 D: 7941
Ptnml(0-2): 41, 772, 3278, 899, 54
passed LTC
https://tests.stockfishchess.org/tests/view/5f51e435ba100690c5cc5f76
LLR: 2.93 (-2.94,2.94) {0.25,1.25}
Total: 30808 W: 1564 L: 1405 D: 27839
Ptnml(0-2): 19, 1245, 12717, 1404, 19
closes https://github.com/official-stockfish/Stockfish/pull/3106
bench 3983758
2020-09-04 06:53:59 -06:00
|
|
|
&& ss->ttHit
|
2012-12-15 03:11:38 -07:00
|
|
|
&& tte->depth() >= depth
|
2015-10-23 23:27:24 -06:00
|
|
|
&& ttValue != VALUE_NONE // Possible in case of TT access race
|
2014-11-12 14:13:55 -07:00
|
|
|
&& (ttValue >= beta ? (tte->bound() & BOUND_LOWER)
|
|
|
|
: (tte->bound() & BOUND_UPPER)))
|
2008-09-06 07:53:43 -06:00
|
|
|
{
|
2017-01-09 03:57:34 -07:00
|
|
|
// If ttMove is quiet, update move sorting heuristics on TT hit
|
2017-01-25 07:32:10 -07:00
|
|
|
if (ttMove)
|
2016-08-24 08:52:05 -06:00
|
|
|
{
|
2017-01-25 07:32:10 -07:00
|
|
|
if (ttValue >= beta)
|
|
|
|
{
|
2020-12-01 05:02:35 -07:00
|
|
|
// Bonus for a quiet ttMove that fails high
|
2017-01-25 07:32:10 -07:00
|
|
|
if (!pos.capture_or_promotion(ttMove))
|
Improve move order near the root
Current move histories are known to work well near the leaves, whilst at
higher depths they aren't very helpful. To address this problem this
patch introduces a table dedicated for what's happening at plies 0-3.
It's structured like mainHistory with ply index instead of color.
It get cleared with each new search and is filled during iterative
deepening at higher depths when recording successful quiet moves near
the root or traversing nodes which were in the principal variation
(ttPv).
Medium TC (20+0.2):
https://tests.stockfishchess.org/tests/view/5e4d358790a0a02810d096dc
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 100910 W: 16682 L: 16376 D: 67852
Ptnml(0-2): 1177, 10983, 25883, 11181, 1231
LTC:
https://tests.stockfishchess.org/tests/view/5e4e2cb790a0a02810d09714
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 80444 W: 10495 L: 10095 D: 59854
Ptnml(0-2): 551, 7479, 23803, 7797, 592
closes https://github.com/official-stockfish/Stockfish/pull/2557
Bench: 4705960
2020-02-21 06:01:59 -07:00
|
|
|
update_quiet_stats(pos, ss, ttMove, stat_bonus(depth), depth);
|
2016-08-24 08:52:05 -06:00
|
|
|
|
2019-04-09 08:51:39 -06:00
|
|
|
// Extra penalty for early quiet moves of the previous ply
|
2019-10-05 08:42:36 -06:00
|
|
|
if ((ss-1)->moveCount <= 2 && !priorCapture)
|
2019-09-28 14:27:23 -06:00
|
|
|
update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + 1));
|
2017-01-25 07:32:10 -07:00
|
|
|
}
|
|
|
|
// Penalty for a quiet ttMove that fails low
|
2017-01-29 00:54:58 -07:00
|
|
|
else if (!pos.capture_or_promotion(ttMove))
|
2017-01-25 07:32:10 -07:00
|
|
|
{
|
Revert 5 recent patches
Revert 5 patches which were merged, but lead to a regression test that showed negative Elo gain:
http://tests.stockfishchess.org/tests/view/5e307251ab2d69d58394fdb9
This was discussed in depth in:
https://github.com/official-stockfish/Stockfish/issues/2531
Each patch was removed and tested as a simplification, full list below, and the whole combo as well.
After the revert the regression test showed a neutral result:
http://tests.stockfishchess.org/tests/view/5e334851708b13464ceea33c
As a result of this experience, the SPRT testing bounds will be made more strict.
Reverted patches:
1 Dynamic Complexity 6d0eabd5fe2961551477820ab7619e2c31e01ffd :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31fcacec661e2e6a340d08 :
LLR: 2.97 (-2.94,2.94) {-1.50,0.50}
Total: 38130 W: 7326 L: 7189 D: 23615
Ptnml(0-2): 677, 4346, 8843, 4545, 646
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c18fec661e2e6a340d73 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 38675 W: 4941 L: 4866 D: 28868
Ptnml(0-2): 270, 3556, 11429, 3584, 291
3 More bonus for bestMoves on past PV nodes 71e0b5385e2717679a57c6b77d8c7ac5fff3b89f :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31fe93ec661e2e6a340d10 :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 46100 W: 8853 L: 8727 D: 28520
Ptnml(0-2): 796, 5297, 10749, 5387, 813
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c187ec661e2e6a340d71 :
LLR: 2.96 (-2.94,2.94) {-1.50,0.50}
Total: 16920 W: 2161 L: 2055 D: 12704
Ptnml(0-2): 115, 1498, 5006, 1569, 130
4 Tweak Restricted Piece Bonus 0ae00454ba6928d181b46103e5c83e6d58fcebe5 :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31fefaec661e2e6a340d15 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 88328 W: 17060 L: 16997 D: 54271
Ptnml(0-2): 1536, 10446, 20169, 10422, 1581
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c17aec661e2e6a340d6f :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 34784 W: 4551 L: 4466 D: 25767
Ptnml(0-2): 255, 3279, 10061, 3345, 262
5 History update for pruned captures 01b6088af39902001d2d6844561b6a2faa549282 :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31ff5eec661e2e6a340d1a :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 29541 W: 5735 L: 5588 D: 18218
Ptnml(0-2): 483, 3445, 6820, 3469, 545
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c196ec661e2e6a340d75 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 22177 W: 2854 L: 2757 D: 16566
Ptnml(0-2): 143, 2005, 6555, 2055, 164
6 Tweak trapped rook penalty 18fc21eba0368fd5e3c4c4b8ee1000c9ac445425 :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31ffb1ec661e2e6a340d1c :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 24476 W: 4727 L: 4569 D: 15180
Ptnml(0-2): 390, 2834, 5659, 2933, 417
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c19eec661e2e6a340d77 :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 97332 W: 12492 L: 12466 D: 72374
Ptnml(0-2): 690, 9107, 28738, 9034, 720
All 5 as one simplification :
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e334098708b13464ceea330 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 7829 W: 1079 L: 964 D: 5786
Ptnml(0-2): 52, 690, 2281, 781, 65
Bench: 5153165
2020-01-30 13:44:04 -07:00
|
|
|
int penalty = -stat_bonus(depth);
|
2018-05-22 12:30:58 -06:00
|
|
|
thisThread->mainHistory[us][from_to(ttMove)] << penalty;
|
2017-06-30 09:20:00 -06:00
|
|
|
update_continuation_histories(ss, pos.moved_piece(ttMove), to_sq(ttMove), penalty);
|
2017-01-25 07:32:10 -07:00
|
|
|
}
|
2016-08-24 08:52:05 -06:00
|
|
|
}
|
50-moves rule improvement for transposition table
User "adentong" reported recently of a game where Stockfish blundered a game
in a tournament because during a search there was an hash-table issue for
positions inside the tree very close to the 50-moves draw rule. This is part
of a problem which is commonly referred to as the Graph History Interaction (GHI),
and is difficult to solve in computer chess because storing the 50-moves counter
in the hash-table loses Elo in general.
Links:
Issue 2451 : https://github.com/official-stockfish/Stockfish/issues/2451
About the GHI : https://www.chessprogramming.org/Graph_History_Interaction
This patch tries to address the issue in this particular game and similar
reported games: it prevents that values from the transposition table are
getting used when the 50-move counter is close to reaching 100 (). The idea
is that in such cases values from previous searches, with a much lower 50-move
count, become less and less reliable.
More precisely, the heuristic we use in this patch is that we don't take the
transposition table cutoff when we have reached a 45-moves limit, but let the
search continue doing its job. There is a possible slowdown involved, but it will
also help to find either a draw when it thought to be losing, or a way to avoid
the draw by 50-move rule. This heuristics probably will not fix all possible cases,
but seems to be working reasonably well in practice while not losing too much Elo.
Passed non-regression tests:
STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 274452 W: 59700 L: 60075 D: 154677
http://tests.stockfishchess.org/tests/view/5df546116932658fe9b451bf
LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 95235 W: 15297 L: 15292 D: 64646
http://tests.stockfishchess.org/tests/view/5df69c926932658fe9b4520e
Closes https://github.com/official-stockfish/Stockfish/pull/2453
Bench: 4586187
2019-12-12 04:53:47 -07:00
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// Partial workaround for the graph history interaction problem
|
|
|
|
// For high rule50 counts don't produce transposition table cutoffs.
|
50-moves rule improvement for transposition table
User "adentong" reported recently of a game where Stockfish blundered a game
in a tournament because during a search there was an hash-table issue for
positions inside the tree very close to the 50-moves draw rule. This is part
of a problem which is commonly referred to as the Graph History Interaction (GHI),
and is difficult to solve in computer chess because storing the 50-moves counter
in the hash-table loses Elo in general.
Links:
Issue 2451 : https://github.com/official-stockfish/Stockfish/issues/2451
About the GHI : https://www.chessprogramming.org/Graph_History_Interaction
This patch tries to address the issue in this particular game and similar
reported games: it prevents that values from the transposition table are
getting used when the 50-move counter is close to reaching 100 (). The idea
is that in such cases values from previous searches, with a much lower 50-move
count, become less and less reliable.
More precisely, the heuristic we use in this patch is that we don't take the
transposition table cutoff when we have reached a 45-moves limit, but let the
search continue doing its job. There is a possible slowdown involved, but it will
also help to find either a draw when it thought to be losing, or a way to avoid
the draw by 50-move rule. This heuristics probably will not fix all possible cases,
but seems to be working reasonably well in practice while not losing too much Elo.
Passed non-regression tests:
STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 274452 W: 59700 L: 60075 D: 154677
http://tests.stockfishchess.org/tests/view/5df546116932658fe9b451bf
LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 95235 W: 15297 L: 15292 D: 64646
http://tests.stockfishchess.org/tests/view/5df69c926932658fe9b4520e
Closes https://github.com/official-stockfish/Stockfish/pull/2453
Bench: 4586187
2019-12-12 04:53:47 -07:00
|
|
|
if (pos.rule50_count() < 90)
|
|
|
|
return ttValue;
|
2008-08-31 23:59:13 -06:00
|
|
|
}
|
|
|
|
|
2018-02-12 14:57:42 -07:00
|
|
|
// Step 5. Tablebases probe
|
2016-01-18 15:20:16 -07:00
|
|
|
if (!rootNode && TB::Cardinality)
|
2015-01-18 00:05:05 -07:00
|
|
|
{
|
2017-03-08 19:45:09 -07:00
|
|
|
int piecesCount = pos.count<ALL_PIECES>();
|
2015-01-18 00:05:05 -07:00
|
|
|
|
2016-12-20 03:18:19 -07:00
|
|
|
if ( piecesCount <= TB::Cardinality
|
|
|
|
&& (piecesCount < TB::Cardinality || depth >= TB::ProbeDepth)
|
2016-01-20 08:24:21 -07:00
|
|
|
&& pos.rule50_count() == 0
|
|
|
|
&& !pos.can_castle(ANY_CASTLING))
|
2015-01-18 00:05:05 -07:00
|
|
|
{
|
2016-07-16 00:10:45 -06:00
|
|
|
TB::ProbeState err;
|
2018-01-28 06:40:07 -07:00
|
|
|
TB::WDLScore wdl = Tablebases::probe_wdl(pos, &err);
|
2015-01-18 00:05:05 -07:00
|
|
|
|
2018-06-04 02:31:25 -06:00
|
|
|
// Force check of time on the next occasion
|
|
|
|
if (thisThread == Threads.main())
|
|
|
|
static_cast<MainThread*>(thisThread)->callsCnt = 0;
|
|
|
|
|
2016-07-16 00:10:45 -06:00
|
|
|
if (err != TB::ProbeState::FAIL)
|
2015-01-18 00:05:05 -07:00
|
|
|
{
|
2017-06-23 23:15:46 -06:00
|
|
|
thisThread->tbHits.fetch_add(1, std::memory_order_relaxed);
|
2015-01-18 00:05:05 -07:00
|
|
|
|
|
|
|
int drawScore = TB::UseRule50 ? 1 : 0;
|
|
|
|
|
Fix for incorrect VALUE_MATE_IN_MAX_PLY usage.
Fixes #2533, fixes #2543, fixes #2423.
the code that prevents false mate announcements depending on the TT
state (GHI), incorrectly used VALUE_MATE_IN_MAX_PLY. The latter
constant, however, also includes, counterintuitively, the TB win range.
This patch fixes that, by restoring the behavior for TB win scores,
while retaining the false mate correctness, and improving the mate
finding ability. In particular
no alse mates are announced with the poisened hash testcase
```
position fen 8/8/8/3k4/8/8/6K1/7R w - - 0 1
go depth 40
position fen 8/8/8/3k4/8/8/6K1/7R w - - 76 1
go depth 20
ucinewgame
```
mates are found with the testcases reported in #2543
```
position fen 4k3/3pp3/8/8/8/8/2PPP3/4K3 w - - 0 1
setoption name Hash value 1024
go depth 55
ucinewgame
```
and
```
position fen 4k3/4p3/8/8/8/8/3PP3/4K3 w - - 0 1
setoption name Hash value 1024
go depth 45
ucinewgame
```
furthermore, on the mate finding benchmark (ChestUCI_23102018.epd),
performance improves over master, roughly reaching performance with the
false mate protection reverted
```
Analyzing 6566 mate positions for best and found mates:
----------------best ---------------found
nodes master revert fixed master revert fixed
16000000 4233 4236 4235 5200 5201 5199
32000000 4583 4585 4585 5417 5424 5418
64000000 4852 4853 4855 5575 5584 5579
128000000 5071 5068 5066 5710 5720 5716
256000000 5280 5282 5279 5819 5827 5826
512000000 5471 5468 5468 5919 5935 5932
```
On a testcase with TB enabled, progress is made consistently, contrary
to master
```
setoption name SyzygyPath value ../../../syzygy/3-4-5/
setoption name Hash value 2048
position fen 1R6/3k4/8/K2p4/4n3/2P5/8/8 w - - 0 1
go depth 58
ucinewgame
```
The PR (prior to a rewrite for clarity)
passed STC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 65405 W: 12454 L: 12384 D: 40567
Ptnml(0-2): 920, 7256, 16285, 7286, 944
http://tests.stockfishchess.org/tests/view/5e441a3be70d848499f63d15
passed LTC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 27096 W: 3477 L: 3413 D: 20206
Ptnml(0-2): 128, 2215, 8776, 2292, 122
http://tests.stockfishchess.org/tests/view/5e44e277e70d848499f63d63
The incorrectly named VALUE_MATE_IN_MAX_PLY and VALUE_MATED_IN_MAX_PLY
were renamed into VALUE_TB_WIN_IN_MAX_PLY and VALUE_TB_LOSS_IN_MAX_PLY,
and correclty defined VALUE_MATE_IN_MAX_PLY and VALUE_MATED_IN_MAX_PLY
were introduced.
One further (corner case) mistake using these constants was fixed (go
mate X), which could lead to a premature return if X > MAX_PLY / 2,
but TB were present.
Thanks to @svivanov72 for one of the reports and help fixing the issue.
closes https://github.com/official-stockfish/Stockfish/pull/2552
Bench: 4932981
2020-02-11 12:42:32 -07:00
|
|
|
// use the range VALUE_MATE_IN_MAX_PLY to VALUE_TB_WIN_IN_MAX_PLY to score
|
|
|
|
value = wdl < -drawScore ? VALUE_MATED_IN_MAX_PLY + ss->ply + 1
|
|
|
|
: wdl > drawScore ? VALUE_MATE_IN_MAX_PLY - ss->ply - 1
|
|
|
|
: VALUE_DRAW + 2 * wdl * drawScore;
|
2015-01-18 00:05:05 -07:00
|
|
|
|
2018-01-28 06:40:07 -07:00
|
|
|
Bound b = wdl < -drawScore ? BOUND_UPPER
|
|
|
|
: wdl > drawScore ? BOUND_LOWER : BOUND_EXACT;
|
2015-01-18 00:05:05 -07:00
|
|
|
|
2018-01-28 06:40:07 -07:00
|
|
|
if ( b == BOUND_EXACT
|
|
|
|
|| (b == BOUND_LOWER ? value >= beta : value <= alpha))
|
|
|
|
{
|
Add / remove leaves from search tree ttPv
add if previous leaf is in search tree and we didn't find a counter move
else remove the position if the leaf is the last one in search tree.
STC : https://tests.stockfishchess.org/tests/view/5f49203c3def640786115314
LLR: 2.95 (-2.94,2.94) {-0.25,1.25}
Total: 29968 W: 3381 L: 3195 D: 23392
Ptnml(0-2): 146, 2432, 9671, 2560, 175
LTC : https://tests.stockfishchess.org/tests/view/5f494bea3def640786115336
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 84952 W: 4619 L: 4333 D: 76000
Ptnml(0-2): 86, 3765, 34481, 4065, 79
closes https://github.com/official-stockfish/Stockfish/pull/3075
Bench 3527337
2020-08-28 04:06:36 -06:00
|
|
|
tte->save(posKey, value_to_tt(value, ss->ply), ss->ttPv, b,
|
2019-09-28 14:27:23 -06:00
|
|
|
std::min(MAX_PLY - 1, depth + 6),
|
2018-07-03 16:58:16 -06:00
|
|
|
MOVE_NONE, VALUE_NONE);
|
2018-01-28 06:40:07 -07:00
|
|
|
|
|
|
|
return value;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (PvNode)
|
|
|
|
{
|
|
|
|
if (b == BOUND_LOWER)
|
|
|
|
bestValue = value, alpha = std::max(alpha, bestValue);
|
|
|
|
else
|
|
|
|
maxValue = value;
|
|
|
|
}
|
2015-01-18 00:05:05 -07:00
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
Introduce capture history pruning
This patch introduces a heuristic that is similar to countermove based pruning but for captures - capture history pruning. The idea is that we can (almost) safely prune really late captures with negative history if they don't give check so will most likely not produce some king-attacking tactic.
passed STC
https://tests.stockfishchess.org/tests/view/5e8c60d40ffd2be7f15e5470
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 23748 W: 4758 L: 4529 D: 14461
Ptnml(0-2): 421, 2712, 5400, 2899, 442
passed LTC
https://tests.stockfishchess.org/tests/view/5e8c72bf0ffd2be7f15e547f
LLR: 2.96 (-2.94,2.94) {0.25,1.75}
Total: 17330 W: 2415 L: 2190 D: 12725
Ptnml(0-2): 126, 1561, 5107, 1704, 167
closes https://github.com/official-stockfish/Stockfish/pull/2618
bench 4417023
2020-04-07 07:53:24 -06:00
|
|
|
CapturePieceToHistory& captureHistory = thisThread->captureHistory;
|
|
|
|
|
2018-05-08 17:40:32 -06:00
|
|
|
// Step 6. Static evaluation of the position
|
continuation histories when in check
If in check, don't write to continuation histories ss-4, ss-6.
Adding inCheck to the stack was needed, and might be useful for
future patches.
Passed STC:
https://tests.stockfishchess.org/tests/view/5e9ee24acaaff5d60a50b812
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 61774 W: 11725 L: 11449 D: 38600
Ptnml(0-2): 971, 7211, 14322, 7337, 1046
Passed LTC:
https://tests.stockfishchess.org/tests/view/5e9eecb7caaff5d60a50b831
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 250822 W: 32067 L: 31179 D: 187576
Ptnml(0-2): 1745, 23126, 74824, 23928, 1788
closes https://github.com/official-stockfish/Stockfish/pull/2645
bench: 4808463
2020-04-21 12:55:41 -06:00
|
|
|
if (ss->inCheck)
|
2013-07-07 05:27:31 -06:00
|
|
|
{
|
2020-06-24 14:19:58 -06:00
|
|
|
// Skip early pruning when in check
|
2019-03-29 07:05:02 -06:00
|
|
|
ss->staticEval = eval = VALUE_NONE;
|
2018-03-13 16:19:36 -06:00
|
|
|
improving = false;
|
2020-06-24 14:19:58 -06:00
|
|
|
goto moves_loop;
|
2013-07-07 05:27:31 -06:00
|
|
|
}
|
Adjust penalty on refuted early quiet moves
This patch changes how previous early moves are penalized in case
search finds a best move. Here, the first quiet move that was not
a transposition table move is penalized.
passed STC
https://tests.stockfishchess.org/tests/view/5f51d839ba100690c5cc5f69
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 10088 W: 1150 L: 997 D: 7941
Ptnml(0-2): 41, 772, 3278, 899, 54
passed LTC
https://tests.stockfishchess.org/tests/view/5f51e435ba100690c5cc5f76
LLR: 2.93 (-2.94,2.94) {0.25,1.25}
Total: 30808 W: 1564 L: 1405 D: 27839
Ptnml(0-2): 19, 1245, 12717, 1404, 19
closes https://github.com/official-stockfish/Stockfish/pull/3106
bench 3983758
2020-09-04 06:53:59 -06:00
|
|
|
else if (ss->ttHit)
|
2010-01-17 04:55:10 -07:00
|
|
|
{
|
2019-06-09 07:07:36 -06:00
|
|
|
// Never assume anything about values stored in TT
|
2019-03-29 07:05:02 -06:00
|
|
|
ss->staticEval = eval = tte->eval();
|
2018-08-28 17:22:22 -06:00
|
|
|
if (eval == VALUE_NONE)
|
2019-03-29 07:05:02 -06:00
|
|
|
ss->staticEval = eval = evaluate(pos);
|
2012-10-26 04:33:58 -06:00
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// Randomize draw evaluation
|
More random draw evaluations
Use the randomized draw function value_draw() also for draw evalutions.
This extends the earlier commit
https://github.com/official-stockfish/Stockfish/commit/97d2cc9a9c1c4b6ff1b470676fa18c7fc6509886
which did this only for 3folds.
As in that case, this test was yellow at STC and LTC, but green at VLTC,
indicative of the fact that the higher the drawrate, the more likely this
idea is beneficial.
STC:
LLR: -2.96 (-2.94,2.94) [0.50,4.50]
Total: 83573 W: 18584 L: 18335 D: 46654
http://tests.stockfishchess.org/tests/view/5d84e44d0ebc5971531d4f94
LTC:
LLR: -2.96 (-2.94,2.94) [0.00,3.50]
Total: 92252 W: 15240 L: 15160 D: 61852
http://tests.stockfishchess.org/tests/view/5d865dd90ebc5971531d68e1
VLTC: 120+1.2 @ 2th
LLR: 2.96 (-2.94,2.94) [0.00,3.50]
Total: 51902 W: 7323 L: 7028 D: 37551
http://tests.stockfishchess.org/tests/view/5d8763620ebc595f57c22b15
Closes https://github.com/official-stockfish/Stockfish/pull/2321
Bench: 3441237
2019-09-20 08:33:57 -06:00
|
|
|
if (eval == VALUE_DRAW)
|
2019-09-27 11:25:22 -06:00
|
|
|
eval = value_draw(thisThread);
|
More random draw evaluations
Use the randomized draw function value_draw() also for draw evalutions.
This extends the earlier commit
https://github.com/official-stockfish/Stockfish/commit/97d2cc9a9c1c4b6ff1b470676fa18c7fc6509886
which did this only for 3folds.
As in that case, this test was yellow at STC and LTC, but green at VLTC,
indicative of the fact that the higher the drawrate, the more likely this
idea is beneficial.
STC:
LLR: -2.96 (-2.94,2.94) [0.50,4.50]
Total: 83573 W: 18584 L: 18335 D: 46654
http://tests.stockfishchess.org/tests/view/5d84e44d0ebc5971531d4f94
LTC:
LLR: -2.96 (-2.94,2.94) [0.00,3.50]
Total: 92252 W: 15240 L: 15160 D: 61852
http://tests.stockfishchess.org/tests/view/5d865dd90ebc5971531d68e1
VLTC: 120+1.2 @ 2th
LLR: 2.96 (-2.94,2.94) [0.00,3.50]
Total: 51902 W: 7323 L: 7028 D: 37551
http://tests.stockfishchess.org/tests/view/5d8763620ebc595f57c22b15
Closes https://github.com/official-stockfish/Stockfish/pull/2321
Bench: 3441237
2019-09-20 08:33:57 -06:00
|
|
|
|
2012-10-22 01:50:00 -06:00
|
|
|
// Can ttValue be used as a better position evaluation?
|
2018-02-12 14:57:42 -07:00
|
|
|
if ( ttValue != VALUE_NONE
|
2017-07-27 03:14:18 -06:00
|
|
|
&& (tte->bound() & (ttValue > eval ? BOUND_LOWER : BOUND_UPPER)))
|
|
|
|
eval = ttValue;
|
2012-12-27 04:13:31 -07:00
|
|
|
}
|
|
|
|
else
|
|
|
|
{
|
2020-12-01 05:02:35 -07:00
|
|
|
// In case of null move search use previous static eval with a different sign
|
|
|
|
// and addition of two tempos
|
2018-08-28 17:22:22 -06:00
|
|
|
if ((ss-1)->currentMove != MOVE_NULL)
|
2020-08-17 06:58:03 -06:00
|
|
|
ss->staticEval = eval = evaluate(pos);
|
2018-08-28 17:22:22 -06:00
|
|
|
else
|
Remove Tempo
The Tempo variable was introduced 10 years ago in our search because the
classical evaluation function was antisymmetrical in White and Black by design
to gain speed:
Eval(White to play) = -Eval(Black to play)
Nowadays our neural networks know which side is to play in a position when
they evaluate a position and are trained on real games, so the neural network
encodes the advantage of moving as an output of search. This patch shows that
the Tempo variable is not necessary anymore.
STC:
LLR: 2.94 (-2.94,2.94) <-2.50,0.50>
Total: 33512 W: 2805 L: 2709 D: 27998
Ptnml(0-2): 80, 2209, 12095, 2279, 93
https://tests.stockfishchess.org/tests/view/60a44ceace8ea25a3ef03d30
LTC:
LLR: 2.95 (-2.94,2.94) <-2.50,0.50>
Total: 53920 W: 1807 L: 1760 D: 50353
Ptnml(0-2): 16, 1617, 23650, 1658, 19
https://tests.stockfishchess.org/tests/view/60a477f0ce8ea25a3ef03d49
We also tried a match (20000 games) at STC using purely classical, result was neutral:
https://tests.stockfishchess.org/tests/view/60a4eebcce8ea25a3ef03db5
Note: there are two locations left in search.cpp where we assume antisymmetry
of evaluation (in relation with a speed optimization for null moves in lines
770 and 1439), but as the values are just used for heuristic pruning this
approximation should not hurt too much because the order of magnitude is still
true most of the time.
closes https://github.com/official-stockfish/Stockfish/pull/3481
Bench: 4015864
2021-05-18 17:24:51 -06:00
|
|
|
ss->staticEval = eval = -(ss-1)->staticEval;
|
Use an affine formula to mix stats and eval
Follow-up for the previous patch: we use an affine formula to mix stats
and evaluation in search. The idea is to give a bonus if the previous
move of the opponent was historically bad, and a malus if the previous
move of the opponent was historically good.
More precisely, if x is the stat score of the previous move by the opponent,
we implement the following formulas to tweak the evaluation at an internal
node of the tree for our pruning decisions at this node:
if x = 0, use v' = eval(P)
if x > 0, use v' = eval(P) - 5 - x/1024
if x < 0, use v' = eval(P) + 5 - x/1024
For reference, the previous master had this simpler rule:
if x > 0, use v' = eval(P) - 10
if x <= 0, use v' = eval(P)
STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 29322 W: 6359 L: 6088 D: 16875
http://tests.stockfishchess.org/tests/view/5b76a5980ebc5902bdba957f
LTC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 30893 W: 5154 L: 4910 D: 20829
http://tests.stockfishchess.org/tests/view/5b76ca6d0ebc5902bdba9914
Closes https://github.com/official-stockfish/Stockfish/pull/1740
Bench: 4592766
2018-08-17 17:23:36 -06:00
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// Save static evaluation into transposition table
|
Add / remove leaves from search tree ttPv
add if previous leaf is in search tree and we didn't find a counter move
else remove the position if the leaf is the last one in search tree.
STC : https://tests.stockfishchess.org/tests/view/5f49203c3def640786115314
LLR: 2.95 (-2.94,2.94) {-0.25,1.25}
Total: 29968 W: 3381 L: 3195 D: 23392
Ptnml(0-2): 146, 2432, 9671, 2560, 175
LTC : https://tests.stockfishchess.org/tests/view/5f494bea3def640786115336
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 84952 W: 4619 L: 4333 D: 76000
Ptnml(0-2): 86, 3765, 34481, 4065, 79
closes https://github.com/official-stockfish/Stockfish/pull/3075
Bench 3527337
2020-08-28 04:06:36 -06:00
|
|
|
tte->save(posKey, VALUE_NONE, ss->ttPv, BOUND_NONE, DEPTH_NONE, MOVE_NONE, eval);
|
2011-10-31 01:28:59 -06:00
|
|
|
}
|
2008-08-31 23:59:13 -06:00
|
|
|
|
Simplify condition for assigning static-eval based bonus
for quiet move ordering and simplify bonus formula.
Due to clamping the bonus to relative low values the impact on high
depths is minimal, thus the restriction to low depths seems not
necessary.
Also the condition of movecount in previous node seems to be not
determinant.
Passed STC:
LLR: 2.95 (-2.94,2.94) {-1.25,0.25}
Total: 14600 W: 1424 L: 1323 D: 11853
Ptnml(0-2): 55, 1033, 5020, 1140, 52
https://tests.stockfishchess.org/tests/view/5fd67b381ac16912018885ec
Passed LTC:
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 85008 W: 3218 L: 3206 D: 78584
Ptnml(0-2): 49, 2840, 36700, 2880, 35
https://tests.stockfishchess.org/tests/view/5fd6af041ac16912018885f8
closes https://github.com/official-stockfish/Stockfish/pull/3265
bench: 4524994
2020-12-14 08:30:56 -07:00
|
|
|
// Use static evaluation difference to improve quiet move ordering
|
|
|
|
if (is_ok((ss-1)->currentMove) && !(ss-1)->inCheck && !priorCapture)
|
Introduce static history
The idea of this patch can be described as following: we update static
history stats based on comparison of the static evaluations of the
position before and after the move. If the move increases static evaluation
it's assigned positive bonus, if it decreases static evaluation
it's assigned negative bonus. These stats are used in movepicker
to sort quiet moves.
passed STC
https://tests.stockfishchess.org/tests/view/5fca4c0842a050a89f02cd66
LLR: 3.00 (-2.94,2.94) {-0.25,1.25}
Total: 78152 W: 7409 L: 7171 D: 63572
Ptnml(0-2): 303, 5695, 26873, 5871, 334
passed LTC
https://tests.stockfishchess.org/tests/view/5fca6be442a050a89f02cd75
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 40240 W: 1602 L: 1441 D: 37197
Ptnml(0-2): 19, 1306, 17305, 1475, 15
closes https://github.com/official-stockfish/Stockfish/pull/3253
bench 3845156
2020-12-04 18:00:41 -07:00
|
|
|
{
|
Remove Tempo
The Tempo variable was introduced 10 years ago in our search because the
classical evaluation function was antisymmetrical in White and Black by design
to gain speed:
Eval(White to play) = -Eval(Black to play)
Nowadays our neural networks know which side is to play in a position when
they evaluate a position and are trained on real games, so the neural network
encodes the advantage of moving as an output of search. This patch shows that
the Tempo variable is not necessary anymore.
STC:
LLR: 2.94 (-2.94,2.94) <-2.50,0.50>
Total: 33512 W: 2805 L: 2709 D: 27998
Ptnml(0-2): 80, 2209, 12095, 2279, 93
https://tests.stockfishchess.org/tests/view/60a44ceace8ea25a3ef03d30
LTC:
LLR: 2.95 (-2.94,2.94) <-2.50,0.50>
Total: 53920 W: 1807 L: 1760 D: 50353
Ptnml(0-2): 16, 1617, 23650, 1658, 19
https://tests.stockfishchess.org/tests/view/60a477f0ce8ea25a3ef03d49
We also tried a match (20000 games) at STC using purely classical, result was neutral:
https://tests.stockfishchess.org/tests/view/60a4eebcce8ea25a3ef03db5
Note: there are two locations left in search.cpp where we assume antisymmetry
of evaluation (in relation with a speed optimization for null moves in lines
770 and 1439), but as the values are just used for heuristic pruning this
approximation should not hurt too much because the order of magnitude is still
true most of the time.
closes https://github.com/official-stockfish/Stockfish/pull/3481
Bench: 4015864
2021-05-18 17:24:51 -06:00
|
|
|
int bonus = std::clamp(-depth * 4 * int((ss-1)->staticEval + ss->staticEval), -1000, 1000);
|
Merge static history into main history,
thus simplifying and reducing the memory footprint.
I believe using static diff for better move ordering is more suited for
low depths, so restrict writing to low depths.
Todo: probably the condition for writing can be simplified
LTC:
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 18752 W: 768 L: 705 D: 17279
Ptnml(0-2): 7, 635, 8034, 688, 12
https://tests.stockfishchess.org/tests/view/5fd631791ac169120188859e
STC:
LLR: 2.95 (-2.94,2.94) {-1.25,0.25}
Total: 36504 W: 3380 L: 3313 D: 29811
Ptnml(0-2): 116, 2667, 12645, 2682, 142
https://tests.stockfishchess.org/tests/view/5fd5ed861ac1691201888569
closes https://github.com/official-stockfish/Stockfish/pull/3262
bench: 4018036
2020-12-13 13:23:30 -07:00
|
|
|
thisThread->mainHistory[~us][from_to((ss-1)->currentMove)] << bonus;
|
Introduce static history
The idea of this patch can be described as following: we update static
history stats based on comparison of the static evaluations of the
position before and after the move. If the move increases static evaluation
it's assigned positive bonus, if it decreases static evaluation
it's assigned negative bonus. These stats are used in movepicker
to sort quiet moves.
passed STC
https://tests.stockfishchess.org/tests/view/5fca4c0842a050a89f02cd66
LLR: 3.00 (-2.94,2.94) {-0.25,1.25}
Total: 78152 W: 7409 L: 7171 D: 63572
Ptnml(0-2): 303, 5695, 26873, 5871, 334
passed LTC
https://tests.stockfishchess.org/tests/view/5fca6be442a050a89f02cd75
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 40240 W: 1602 L: 1441 D: 37197
Ptnml(0-2): 19, 1306, 17305, 1475, 15
closes https://github.com/official-stockfish/Stockfish/pull/3253
bench 3845156
2020-12-04 18:00:41 -07:00
|
|
|
}
|
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// Set up improving flag that is used in various pruning heuristics
|
|
|
|
// We define position as improving if static evaluation of position is better
|
|
|
|
// Than the previous static evaluation at our turn
|
|
|
|
// In case of us being in check at our previous move we look at move prior to it
|
2020-07-11 08:59:33 -06:00
|
|
|
improving = (ss-2)->staticEval == VALUE_NONE
|
|
|
|
? ss->staticEval > (ss-4)->staticEval || (ss-4)->staticEval == VALUE_NONE
|
|
|
|
: ss->staticEval > (ss-2)->staticEval;
|
2018-05-08 17:40:32 -06:00
|
|
|
|
Remove razoring
has become ineffective now.
STC https://tests.stockfishchess.org/tests/view/5fe653403932f79192d3981a
LLR: 2.95 (-2.94,2.94) {-1.25,0.25}
Total: 63448 W: 5965 L: 5934 D: 51549
Ptnml(0-2): 230, 4738, 21769, 4745, 242
LTC https://tests.stockfishchess.org/tests/view/5fe6f0f03932f79192d39856
LLR: 2.93 (-2.94,2.94) {-0.75,0.25}
Total: 65368 W: 2485 L: 2459 D: 60424
Ptnml(0-2): 33, 2186, 28230, 2192, 43
closes https://github.com/official-stockfish/Stockfish/pull/3278
bench: 4493379
2020-12-26 05:48:04 -07:00
|
|
|
// Step 7. Futility pruning: child node (~50 Elo)
|
2018-12-12 12:34:17 -07:00
|
|
|
if ( !PvNode
|
Assorted parameter tweak
Parameter tweak from various tunes and patches.
STC https://tests.stockfishchess.org/tests/view/5fec2ae36019e097de3ee94a
LLR: 2.97 (-2.94,2.94) {-0.25,1.25}
Total: 41976 W: 4032 L: 3848 D: 34096
Ptnml(0-2): 147, 3086, 14341, 3264, 150
LTC https://tests.stockfishchess.org/tests/view/5fec5c3c6019e097de3ee973
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 23936 W: 970 L: 844 D: 22122
Ptnml(0-2): 14, 749, 10319, 869, 17
closes https://github.com/official-stockfish/Stockfish/pull/3281
bench: 4354546
2020-12-30 07:38:25 -07:00
|
|
|
&& depth < 9
|
2018-03-07 14:31:51 -07:00
|
|
|
&& eval - futility_margin(depth, improving) >= beta
|
2018-02-12 14:57:42 -07:00
|
|
|
&& eval < VALUE_KNOWN_WIN) // Do not return unproven wins
|
2016-10-07 23:06:33 -06:00
|
|
|
return eval;
|
2010-01-21 10:03:06 -07:00
|
|
|
|
Remove razoring
has become ineffective now.
STC https://tests.stockfishchess.org/tests/view/5fe653403932f79192d3981a
LLR: 2.95 (-2.94,2.94) {-1.25,0.25}
Total: 63448 W: 5965 L: 5934 D: 51549
Ptnml(0-2): 230, 4738, 21769, 4745, 242
LTC https://tests.stockfishchess.org/tests/view/5fe6f0f03932f79192d39856
LLR: 2.93 (-2.94,2.94) {-0.75,0.25}
Total: 65368 W: 2485 L: 2459 D: 60424
Ptnml(0-2): 33, 2186, 28230, 2192, 43
closes https://github.com/official-stockfish/Stockfish/pull/3278
bench: 4493379
2020-12-26 05:48:04 -07:00
|
|
|
// Step 8. Null move search with verification search (~40 Elo)
|
2010-05-08 02:54:51 -06:00
|
|
|
if ( !PvNode
|
2018-05-08 02:43:46 -06:00
|
|
|
&& (ss-1)->currentMove != MOVE_NULL
|
Tuning Search
This patch tunes constant in search.cpp
STC:
LLR: 2.94 (-2.94,2.94) <-0.50,2.50>
Total: 30648 W: 2580 L: 2410 D: 25658
Ptnml(0-2): 80, 1969, 11093, 2065, 117
https://tests.stockfishchess.org/tests/view/60a71d3cce8ea25a3ef03fae
LTC:
LLR: 2.95 (-2.94,2.94) <0.50,3.50>
Total: 52896 W: 1776 L: 1617 D: 49503
Ptnml(0-2): 13, 1462, 23347, 1605, 21
https://tests.stockfishchess.org/tests/view/60a794ddce8ea25a3ef0400a
closes https://github.com/official-stockfish/Stockfish/pull/3491
Bench: 4004731
2021-05-21 23:47:23 -06:00
|
|
|
&& (ss-1)->statScore < 23767
|
2012-10-22 01:50:00 -06:00
|
|
|
&& eval >= beta
|
2019-08-14 18:46:09 -06:00
|
|
|
&& eval >= ss->staticEval
|
Tuning Search
This patch tunes constant in search.cpp
STC:
LLR: 2.94 (-2.94,2.94) <-0.50,2.50>
Total: 30648 W: 2580 L: 2410 D: 25658
Ptnml(0-2): 80, 1969, 11093, 2065, 117
https://tests.stockfishchess.org/tests/view/60a71d3cce8ea25a3ef03fae
LTC:
LLR: 2.95 (-2.94,2.94) <0.50,3.50>
Total: 52896 W: 1776 L: 1617 D: 49503
Ptnml(0-2): 13, 1462, 23347, 1605, 21
https://tests.stockfishchess.org/tests/view/60a794ddce8ea25a3ef0400a
closes https://github.com/official-stockfish/Stockfish/pull/3491
Bench: 4004731
2021-05-21 23:47:23 -06:00
|
|
|
&& ss->staticEval >= beta - 20 * depth - 22 * improving + 168 * ss->ttPv + 159
|
2018-05-13 22:52:16 -06:00
|
|
|
&& !excludedMove
|
2018-05-22 12:30:58 -06:00
|
|
|
&& pos.non_pawn_material(us)
|
2018-06-04 01:10:30 -06:00
|
|
|
&& (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor))
|
2009-08-29 13:19:09 -06:00
|
|
|
{
|
2014-01-24 13:52:56 -07:00
|
|
|
assert(eval - beta >= 0);
|
2009-11-13 03:25:34 -07:00
|
|
|
|
2014-01-24 13:52:56 -07:00
|
|
|
// Null move dynamic reduction based on depth and value
|
Tuning Search
This patch tunes constant in search.cpp
STC:
LLR: 2.94 (-2.94,2.94) <-0.50,2.50>
Total: 30648 W: 2580 L: 2410 D: 25658
Ptnml(0-2): 80, 1969, 11093, 2065, 117
https://tests.stockfishchess.org/tests/view/60a71d3cce8ea25a3ef03fae
LTC:
LLR: 2.95 (-2.94,2.94) <0.50,3.50>
Total: 52896 W: 1776 L: 1617 D: 49503
Ptnml(0-2): 13, 1462, 23347, 1605, 21
https://tests.stockfishchess.org/tests/view/60a794ddce8ea25a3ef0400a
closes https://github.com/official-stockfish/Stockfish/pull/3491
Bench: 4004731
2021-05-21 23:47:23 -06:00
|
|
|
Depth R = (1090 + 81 * depth) / 256 + std::min(int(eval - beta) / 205, 3);
|
2009-08-29 13:19:09 -06:00
|
|
|
|
2017-03-08 19:35:23 -07:00
|
|
|
ss->currentMove = MOVE_NULL;
|
2019-10-08 08:44:01 -06:00
|
|
|
ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0];
|
2017-03-08 19:35:23 -07:00
|
|
|
|
2013-01-27 03:45:01 -07:00
|
|
|
pos.do_null_move(st);
|
2018-03-15 02:21:34 -06:00
|
|
|
|
2018-05-08 02:43:46 -06:00
|
|
|
Value nullValue = -search<NonPV>(pos, ss+1, -beta, -beta+1, depth-R, !cutNode);
|
2018-03-15 02:21:34 -06:00
|
|
|
|
2013-01-27 03:45:01 -07:00
|
|
|
pos.undo_null_move();
|
2009-08-24 08:46:03 -06:00
|
|
|
|
2014-02-12 06:16:21 -07:00
|
|
|
if (nullValue >= beta)
|
|
|
|
{
|
2020-03-30 14:45:35 -06:00
|
|
|
// Do not return unproven mate or TB scores
|
Fix for incorrect VALUE_MATE_IN_MAX_PLY usage.
Fixes #2533, fixes #2543, fixes #2423.
the code that prevents false mate announcements depending on the TT
state (GHI), incorrectly used VALUE_MATE_IN_MAX_PLY. The latter
constant, however, also includes, counterintuitively, the TB win range.
This patch fixes that, by restoring the behavior for TB win scores,
while retaining the false mate correctness, and improving the mate
finding ability. In particular
no alse mates are announced with the poisened hash testcase
```
position fen 8/8/8/3k4/8/8/6K1/7R w - - 0 1
go depth 40
position fen 8/8/8/3k4/8/8/6K1/7R w - - 76 1
go depth 20
ucinewgame
```
mates are found with the testcases reported in #2543
```
position fen 4k3/3pp3/8/8/8/8/2PPP3/4K3 w - - 0 1
setoption name Hash value 1024
go depth 55
ucinewgame
```
and
```
position fen 4k3/4p3/8/8/8/8/3PP3/4K3 w - - 0 1
setoption name Hash value 1024
go depth 45
ucinewgame
```
furthermore, on the mate finding benchmark (ChestUCI_23102018.epd),
performance improves over master, roughly reaching performance with the
false mate protection reverted
```
Analyzing 6566 mate positions for best and found mates:
----------------best ---------------found
nodes master revert fixed master revert fixed
16000000 4233 4236 4235 5200 5201 5199
32000000 4583 4585 4585 5417 5424 5418
64000000 4852 4853 4855 5575 5584 5579
128000000 5071 5068 5066 5710 5720 5716
256000000 5280 5282 5279 5819 5827 5826
512000000 5471 5468 5468 5919 5935 5932
```
On a testcase with TB enabled, progress is made consistently, contrary
to master
```
setoption name SyzygyPath value ../../../syzygy/3-4-5/
setoption name Hash value 2048
position fen 1R6/3k4/8/K2p4/4n3/2P5/8/8 w - - 0 1
go depth 58
ucinewgame
```
The PR (prior to a rewrite for clarity)
passed STC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 65405 W: 12454 L: 12384 D: 40567
Ptnml(0-2): 920, 7256, 16285, 7286, 944
http://tests.stockfishchess.org/tests/view/5e441a3be70d848499f63d15
passed LTC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 27096 W: 3477 L: 3413 D: 20206
Ptnml(0-2): 128, 2215, 8776, 2292, 122
http://tests.stockfishchess.org/tests/view/5e44e277e70d848499f63d63
The incorrectly named VALUE_MATE_IN_MAX_PLY and VALUE_MATED_IN_MAX_PLY
were renamed into VALUE_TB_WIN_IN_MAX_PLY and VALUE_TB_LOSS_IN_MAX_PLY,
and correclty defined VALUE_MATE_IN_MAX_PLY and VALUE_MATED_IN_MAX_PLY
were introduced.
One further (corner case) mistake using these constants was fixed (go
mate X), which could lead to a premature return if X > MAX_PLY / 2,
but TB were present.
Thanks to @svivanov72 for one of the reports and help fixing the issue.
closes https://github.com/official-stockfish/Stockfish/pull/2552
Bench: 4932981
2020-02-11 12:42:32 -07:00
|
|
|
if (nullValue >= VALUE_TB_WIN_IN_MAX_PLY)
|
2014-02-12 06:16:21 -07:00
|
|
|
nullValue = beta;
|
|
|
|
|
Assorted search and eval parameter tune
Search and eval parameter tune.
STC https://tests.stockfishchess.org/tests/view/5fba850a67cbf42301d6b07d
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 24312 W: 2388 L: 2228 D: 19696
Ptnml(0-2): 85, 1800, 8241, 1930, 100
LTC https://tests.stockfishchess.org/tests/view/5fbad5ea67cbf42301d6b0fa
LLR: 2.95 (-2.94,2.94) {0.25,1.25}
Total: 88376 W: 3619 L: 3351 D: 81406
Ptnml(0-2): 56, 2977, 37849, 3255, 51
closes https://github.com/official-stockfish/Stockfish/pull/3232
bench: 3600361
2020-11-24 09:06:30 -07:00
|
|
|
if (thisThread->nmpMinPly || (abs(beta) < VALUE_KNOWN_WIN && depth < 14))
|
2014-02-12 06:16:21 -07:00
|
|
|
return nullValue;
|
|
|
|
|
2018-06-02 09:41:37 -06:00
|
|
|
assert(!thisThread->nmpMinPly); // Recursive verification is not allowed
|
2018-05-24 10:26:21 -06:00
|
|
|
|
|
|
|
// Do verification search at high depths, with null move pruning disabled
|
2018-06-02 09:41:37 -06:00
|
|
|
// for us, until ply exceeds nmpMinPly.
|
2019-09-28 14:27:23 -06:00
|
|
|
thisThread->nmpMinPly = ss->ply + 3 * (depth-R) / 4;
|
2018-06-02 09:41:37 -06:00
|
|
|
thisThread->nmpColor = us;
|
2017-12-18 08:30:27 -07:00
|
|
|
|
2018-05-08 02:43:46 -06:00
|
|
|
Value v = search<NonPV>(pos, ss, beta-1, beta, depth-R, false);
|
2018-01-13 01:01:23 -07:00
|
|
|
|
2018-06-02 09:41:37 -06:00
|
|
|
thisThread->nmpMinPly = 0;
|
2014-02-12 06:16:21 -07:00
|
|
|
|
|
|
|
if (v >= beta)
|
|
|
|
return nullValue;
|
|
|
|
}
|
2009-08-29 13:19:09 -06:00
|
|
|
}
|
2008-08-31 23:59:13 -06:00
|
|
|
|
Search Parameters Tuning
A simple tuning on search.cpp.
based SPSA test:
https://tests.stockfishchess.org/tests/view/601f2a787f517a561bc493cd
passed STC:
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 117840 W: 10796 L: 10508 D: 96536
Ptnml(0-2): 422, 8381, 41041, 8639, 437
https://tests.stockfishchess.org/tests/view/602144c37f517a561bc494ae
passed LTC:
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 25024 W: 972 L: 847 D: 23205
Ptnml(0-2): 7, 767, 10847, 876, 15
https://tests.stockfishchess.org/tests/view/602156877f517a561bc494be
closes https://github.com/official-stockfish/Stockfish/pull/3340
Bench: 3974098
2021-02-04 17:50:22 -07:00
|
|
|
probCutBeta = beta + 209 - 44 * improving;
|
Maximize usage of transposition table in probcut
Probcut is a heuristic that wasn't changed a lot in past years,
all attempts to change it using information / writing info to transposition table failed.
This patch has a number of differences that can be summarized as follows:
* For TT write/read we use depth - 3. Because probcut search is depth - 4 but we actually do the move prior to it so effectively we do depth - 3 search;
* In any case of depth of eval from transposition table being >= depth - 3 we either produce cutoff or refuse to even do probcut search, this is allowing us to write info of probcut to transposition table because we know that we wouldn't be overwriting some deeper data with our depth - 3 search - this is an important aspect of this patch;
* For some not really known reason this patch completely ignores tte->bound() - which was the case for previous patch that made probcut interact with TT, maybe 2) is the reason, although it's unproven.
A first version of this patch passed STC and LTC
passed STC
https://tests.stockfishchess.org/tests/view/5f05908a59f6f03532894613
LLR: 2.95 (-2.94,2.94) {-0.50,1.50}
Total: 95776 W: 18300 L: 17973 D: 59503
Ptnml(0-2): 1646, 10944, 22377, 11279, 1642
passed LTC
https://tests.stockfishchess.org/tests/view/5f06b54059f6f035328946bb
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 57128 W: 7266 L: 6938 D: 42924
Ptnml(0-2): 372, 5163, 17217, 5389, 423
However, an additional bugfix was needed to avoid checking a condition on ttMove if was not available. This passed non-regression bounds on top of the first version:
at STC
https://tests.stockfishchess.org/tests/view/5f080e5059f6f03532894766
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 14096 W: 2800 L: 2628 D: 8668
Ptnml(0-2): 225, 1620, 3238, 1688, 277
at LTC
https://tests.stockfishchess.org/tests/view/5f0836a559f6f0353289479c
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 25352 W: 3228 L: 3139 D: 18985
Ptnml(0-2): 175, 2350, 7549, 2415, 187
closes https://github.com/official-stockfish/Stockfish/pull/2804
Bench 4540940
2020-07-10 15:06:55 -06:00
|
|
|
|
Remove early return in Probcut code
We simplify away early return in ProbCut, as it seems not to bring any strength anymore.
STC:
LLR: 2.93 (-2.94,2.94) <-2.50,0.50>
Total: 42632 W: 3705 L: 3617 D: 35310
Ptnml(0-2): 123, 2947, 15110, 2991, 145
https://tests.stockfishchess.org/tests/view/609c49da7746e3dc74ffae02
LTC:
LLR: 2.96 (-2.94,2.94) <-2.50,0.50>
Total: 35384 W: 1314 L: 1251 D: 32819
Ptnml(0-2): 11, 1130, 15355, 1177, 19
https://tests.stockfishchess.org/tests/view/609c71467746e3dc74ffae47
---
While at it, we also update the Elo estimate of ProbCut
(see https://tests.stockfishchess.org/tests/view/609bfb597746e3dc74ffabe3).
closes https://github.com/official-stockfish/Stockfish/pull/3462
bench: 3764662
2021-05-13 08:12:56 -06:00
|
|
|
// Step 9. ProbCut (~4 Elo)
|
2016-08-28 04:39:49 -06:00
|
|
|
// If we have a good enough capture and a reduced search returns a value
|
|
|
|
// much above beta, we can (almost) safely prune the previous move.
|
2011-05-21 10:17:11 -06:00
|
|
|
if ( !PvNode
|
Retuned values after eval quantize patch.
The last search tune patch was tested before the implementation of #2733 which
presumably changed the search characteristics noticeably. Another tuning run was
done, see https://tests.stockfishchess.org/tests/view/5ee5b434ca6c451633a9a08c
and the updated values passed these tests:
STC:
LLR: 2.93 (-2.94,2.94) {-0.50,1.50}
Total: 34352 W: 6600 L: 6360 D: 21392
Ptnml(0-2): 581, 3947, 7914, 4119, 615
https://tests.stockfishchess.org/tests/view/5ee62f05ca6c451633a9a15f
LTC 60+0.6 th 1 :
LLR: 2.97 (-2.94,2.94) {0.25,1.75}
Total: 11176 W: 1499 L: 1304 D: 8373
Ptnml(0-2): 69, 933, 3403, 1100, 83
https://tests.stockfishchess.org/tests/view/5ee6205bca6c451633a9a147
SMP LTC 20+0.2 th 8 :
LLR: 2.93 (-2.94,2.94) {0.25,1.75}
Total: 54032 W: 6126 L: 5826 D: 42080
Ptnml(0-2): 278, 4454, 17280, 4698, 306
https://tests.stockfishchess.org/tests/view/5ee62f25ca6c451633a9a162
Closes https://github.com/official-stockfish/Stockfish/pull/2742
Bench 4957812
2020-06-14 14:50:27 -06:00
|
|
|
&& depth > 4
|
Maximize usage of transposition table in probcut
Probcut is a heuristic that wasn't changed a lot in past years,
all attempts to change it using information / writing info to transposition table failed.
This patch has a number of differences that can be summarized as follows:
* For TT write/read we use depth - 3. Because probcut search is depth - 4 but we actually do the move prior to it so effectively we do depth - 3 search;
* In any case of depth of eval from transposition table being >= depth - 3 we either produce cutoff or refuse to even do probcut search, this is allowing us to write info of probcut to transposition table because we know that we wouldn't be overwriting some deeper data with our depth - 3 search - this is an important aspect of this patch;
* For some not really known reason this patch completely ignores tte->bound() - which was the case for previous patch that made probcut interact with TT, maybe 2) is the reason, although it's unproven.
A first version of this patch passed STC and LTC
passed STC
https://tests.stockfishchess.org/tests/view/5f05908a59f6f03532894613
LLR: 2.95 (-2.94,2.94) {-0.50,1.50}
Total: 95776 W: 18300 L: 17973 D: 59503
Ptnml(0-2): 1646, 10944, 22377, 11279, 1642
passed LTC
https://tests.stockfishchess.org/tests/view/5f06b54059f6f035328946bb
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 57128 W: 7266 L: 6938 D: 42924
Ptnml(0-2): 372, 5163, 17217, 5389, 423
However, an additional bugfix was needed to avoid checking a condition on ttMove if was not available. This passed non-regression bounds on top of the first version:
at STC
https://tests.stockfishchess.org/tests/view/5f080e5059f6f03532894766
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 14096 W: 2800 L: 2628 D: 8668
Ptnml(0-2): 225, 1620, 3238, 1688, 277
at LTC
https://tests.stockfishchess.org/tests/view/5f0836a559f6f0353289479c
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 25352 W: 3228 L: 3139 D: 18985
Ptnml(0-2): 175, 2350, 7549, 2415, 187
closes https://github.com/official-stockfish/Stockfish/pull/2804
Bench 4540940
2020-07-10 15:06:55 -06:00
|
|
|
&& abs(beta) < VALUE_TB_WIN_IN_MAX_PLY
|
2020-07-18 07:30:00 -06:00
|
|
|
// if value from transposition table is lower than probCutBeta, don't attempt probCut
|
|
|
|
// there and in further interactions with transposition table cutoff depth is set to depth - 3
|
|
|
|
// because probCut search has depth set to depth - 4 but we also do a move before it
|
|
|
|
// so effective depth is equal to depth - 3
|
Adjust penalty on refuted early quiet moves
This patch changes how previous early moves are penalized in case
search finds a best move. Here, the first quiet move that was not
a transposition table move is penalized.
passed STC
https://tests.stockfishchess.org/tests/view/5f51d839ba100690c5cc5f69
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 10088 W: 1150 L: 997 D: 7941
Ptnml(0-2): 41, 772, 3278, 899, 54
passed LTC
https://tests.stockfishchess.org/tests/view/5f51e435ba100690c5cc5f76
LLR: 2.93 (-2.94,2.94) {0.25,1.25}
Total: 30808 W: 1564 L: 1405 D: 27839
Ptnml(0-2): 19, 1245, 12717, 1404, 19
closes https://github.com/official-stockfish/Stockfish/pull/3106
bench 3983758
2020-09-04 06:53:59 -06:00
|
|
|
&& !( ss->ttHit
|
2020-07-11 08:59:33 -06:00
|
|
|
&& tte->depth() >= depth - 3
|
Maximize usage of transposition table in probcut
Probcut is a heuristic that wasn't changed a lot in past years,
all attempts to change it using information / writing info to transposition table failed.
This patch has a number of differences that can be summarized as follows:
* For TT write/read we use depth - 3. Because probcut search is depth - 4 but we actually do the move prior to it so effectively we do depth - 3 search;
* In any case of depth of eval from transposition table being >= depth - 3 we either produce cutoff or refuse to even do probcut search, this is allowing us to write info of probcut to transposition table because we know that we wouldn't be overwriting some deeper data with our depth - 3 search - this is an important aspect of this patch;
* For some not really known reason this patch completely ignores tte->bound() - which was the case for previous patch that made probcut interact with TT, maybe 2) is the reason, although it's unproven.
A first version of this patch passed STC and LTC
passed STC
https://tests.stockfishchess.org/tests/view/5f05908a59f6f03532894613
LLR: 2.95 (-2.94,2.94) {-0.50,1.50}
Total: 95776 W: 18300 L: 17973 D: 59503
Ptnml(0-2): 1646, 10944, 22377, 11279, 1642
passed LTC
https://tests.stockfishchess.org/tests/view/5f06b54059f6f035328946bb
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 57128 W: 7266 L: 6938 D: 42924
Ptnml(0-2): 372, 5163, 17217, 5389, 423
However, an additional bugfix was needed to avoid checking a condition on ttMove if was not available. This passed non-regression bounds on top of the first version:
at STC
https://tests.stockfishchess.org/tests/view/5f080e5059f6f03532894766
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 14096 W: 2800 L: 2628 D: 8668
Ptnml(0-2): 225, 1620, 3238, 1688, 277
at LTC
https://tests.stockfishchess.org/tests/view/5f0836a559f6f0353289479c
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 25352 W: 3228 L: 3139 D: 18985
Ptnml(0-2): 175, 2350, 7549, 2415, 187
closes https://github.com/official-stockfish/Stockfish/pull/2804
Bench 4540940
2020-07-10 15:06:55 -06:00
|
|
|
&& ttValue != VALUE_NONE
|
2020-07-18 07:30:00 -06:00
|
|
|
&& ttValue < probCutBeta))
|
2011-05-21 10:17:11 -06:00
|
|
|
{
|
2020-07-18 07:30:00 -06:00
|
|
|
assert(probCutBeta < VALUE_INFINITE);
|
2021-03-19 12:43:25 -06:00
|
|
|
|
2020-07-18 07:30:00 -06:00
|
|
|
MovePicker mp(pos, ttMove, probCutBeta - ss->staticEval, &captureHistory);
|
2018-03-03 04:03:38 -07:00
|
|
|
int probCutCount = 0;
|
Add / remove leaves from search tree ttPv
add if previous leaf is in search tree and we didn't find a counter move
else remove the position if the leaf is the last one in search tree.
STC : https://tests.stockfishchess.org/tests/view/5f49203c3def640786115314
LLR: 2.95 (-2.94,2.94) {-0.25,1.25}
Total: 29968 W: 3381 L: 3195 D: 23392
Ptnml(0-2): 146, 2432, 9671, 2560, 175
LTC : https://tests.stockfishchess.org/tests/view/5f494bea3def640786115336
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 84952 W: 4619 L: 4333 D: 76000
Ptnml(0-2): 86, 3765, 34481, 4065, 79
closes https://github.com/official-stockfish/Stockfish/pull/3075
Bench 3527337
2020-08-28 04:06:36 -06:00
|
|
|
bool ttPv = ss->ttPv;
|
|
|
|
ss->ttPv = false;
|
2018-03-06 14:11:45 -07:00
|
|
|
|
Don't attempt probcut if ttMove is not good enough.
This idea is loosely based on xoroshiro idea about raisedBeta and ttmoves.
If our ttmove have low enough ttvalue and is deep enough (deeper than our probcut depth) it makes little sense to try probcut moves, since the ttMove already more or less failed to produce one according to transposition table.
passed STC
https://tests.stockfishchess.org/tests/view/5e9673ddc2718dee3c822920
LLR: 2.95 (-2.94,2.94) {-0.50,1.50}
Total: 72148 W: 14038 L: 13741 D: 44369
Ptnml(0-2): 1274, 8326, 16615, 8547, 1312
passed LTC
https://tests.stockfishchess.org/tests/view/5e96b378c2718dee3c8229bf
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 89054 W: 11418 L: 10996 D: 66640
Ptnml(0-2): 623, 8113, 26643, 8515, 633
closes https://github.com/official-stockfish/Stockfish/pull/2632
bench 4952731
2020-04-15 09:22:02 -06:00
|
|
|
while ( (move = mp.next_move()) != MOVE_NONE
|
Maximize usage of transposition table in probcut
Probcut is a heuristic that wasn't changed a lot in past years,
all attempts to change it using information / writing info to transposition table failed.
This patch has a number of differences that can be summarized as follows:
* For TT write/read we use depth - 3. Because probcut search is depth - 4 but we actually do the move prior to it so effectively we do depth - 3 search;
* In any case of depth of eval from transposition table being >= depth - 3 we either produce cutoff or refuse to even do probcut search, this is allowing us to write info of probcut to transposition table because we know that we wouldn't be overwriting some deeper data with our depth - 3 search - this is an important aspect of this patch;
* For some not really known reason this patch completely ignores tte->bound() - which was the case for previous patch that made probcut interact with TT, maybe 2) is the reason, although it's unproven.
A first version of this patch passed STC and LTC
passed STC
https://tests.stockfishchess.org/tests/view/5f05908a59f6f03532894613
LLR: 2.95 (-2.94,2.94) {-0.50,1.50}
Total: 95776 W: 18300 L: 17973 D: 59503
Ptnml(0-2): 1646, 10944, 22377, 11279, 1642
passed LTC
https://tests.stockfishchess.org/tests/view/5f06b54059f6f035328946bb
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 57128 W: 7266 L: 6938 D: 42924
Ptnml(0-2): 372, 5163, 17217, 5389, 423
However, an additional bugfix was needed to avoid checking a condition on ttMove if was not available. This passed non-regression bounds on top of the first version:
at STC
https://tests.stockfishchess.org/tests/view/5f080e5059f6f03532894766
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 14096 W: 2800 L: 2628 D: 8668
Ptnml(0-2): 225, 1620, 3238, 1688, 277
at LTC
https://tests.stockfishchess.org/tests/view/5f0836a559f6f0353289479c
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 25352 W: 3228 L: 3139 D: 18985
Ptnml(0-2): 175, 2350, 7549, 2415, 187
closes https://github.com/official-stockfish/Stockfish/pull/2804
Bench 4540940
2020-07-10 15:06:55 -06:00
|
|
|
&& probCutCount < 2 + 2 * cutNode)
|
2018-08-28 18:27:47 -06:00
|
|
|
if (move != excludedMove && pos.legal(move))
|
2011-05-21 10:17:11 -06:00
|
|
|
{
|
2019-10-18 07:23:00 -06:00
|
|
|
assert(pos.capture_or_promotion(move));
|
|
|
|
assert(depth >= 5);
|
|
|
|
|
|
|
|
captureOrPromotion = true;
|
2018-03-03 04:03:38 -07:00
|
|
|
probCutCount++;
|
|
|
|
|
2012-01-21 15:30:56 -07:00
|
|
|
ss->currentMove = move;
|
continuation histories when in check
If in check, don't write to continuation histories ss-4, ss-6.
Adding inCheck to the stack was needed, and might be useful for
future patches.
Passed STC:
https://tests.stockfishchess.org/tests/view/5e9ee24acaaff5d60a50b812
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 61774 W: 11725 L: 11449 D: 38600
Ptnml(0-2): 971, 7211, 14322, 7337, 1046
Passed LTC:
https://tests.stockfishchess.org/tests/view/5e9eecb7caaff5d60a50b831
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 250822 W: 32067 L: 31179 D: 187576
Ptnml(0-2): 1745, 23126, 74824, 23928, 1788
closes https://github.com/official-stockfish/Stockfish/pull/2645
bench: 4808463
2020-04-21 12:55:41 -06:00
|
|
|
ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck]
|
2019-10-18 07:23:00 -06:00
|
|
|
[captureOrPromotion]
|
|
|
|
[pos.moved_piece(move)]
|
|
|
|
[to_sq(move)];
|
2018-02-12 14:57:42 -07:00
|
|
|
|
2016-11-11 06:02:28 -07:00
|
|
|
pos.do_move(move, st);
|
2018-02-25 19:01:37 -07:00
|
|
|
|
2018-03-13 01:20:20 -06:00
|
|
|
// Perform a preliminary qsearch to verify that the move holds
|
2020-07-18 07:30:00 -06:00
|
|
|
value = -qsearch<NonPV>(pos, ss+1, -probCutBeta, -probCutBeta+1);
|
2018-03-13 01:20:20 -06:00
|
|
|
|
2019-02-08 02:36:03 -07:00
|
|
|
// If the qsearch held, perform the regular search
|
2020-07-18 07:30:00 -06:00
|
|
|
if (value >= probCutBeta)
|
|
|
|
value = -search<NonPV>(pos, ss+1, -probCutBeta, -probCutBeta+1, depth - 4, !cutNode);
|
2018-02-25 19:01:37 -07:00
|
|
|
|
2011-05-21 10:17:11 -06:00
|
|
|
pos.undo_move(move);
|
2018-03-02 03:38:11 -07:00
|
|
|
|
2020-07-18 07:30:00 -06:00
|
|
|
if (value >= probCutBeta)
|
Maximize usage of transposition table in probcut
Probcut is a heuristic that wasn't changed a lot in past years,
all attempts to change it using information / writing info to transposition table failed.
This patch has a number of differences that can be summarized as follows:
* For TT write/read we use depth - 3. Because probcut search is depth - 4 but we actually do the move prior to it so effectively we do depth - 3 search;
* In any case of depth of eval from transposition table being >= depth - 3 we either produce cutoff or refuse to even do probcut search, this is allowing us to write info of probcut to transposition table because we know that we wouldn't be overwriting some deeper data with our depth - 3 search - this is an important aspect of this patch;
* For some not really known reason this patch completely ignores tte->bound() - which was the case for previous patch that made probcut interact with TT, maybe 2) is the reason, although it's unproven.
A first version of this patch passed STC and LTC
passed STC
https://tests.stockfishchess.org/tests/view/5f05908a59f6f03532894613
LLR: 2.95 (-2.94,2.94) {-0.50,1.50}
Total: 95776 W: 18300 L: 17973 D: 59503
Ptnml(0-2): 1646, 10944, 22377, 11279, 1642
passed LTC
https://tests.stockfishchess.org/tests/view/5f06b54059f6f035328946bb
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 57128 W: 7266 L: 6938 D: 42924
Ptnml(0-2): 372, 5163, 17217, 5389, 423
However, an additional bugfix was needed to avoid checking a condition on ttMove if was not available. This passed non-regression bounds on top of the first version:
at STC
https://tests.stockfishchess.org/tests/view/5f080e5059f6f03532894766
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 14096 W: 2800 L: 2628 D: 8668
Ptnml(0-2): 225, 1620, 3238, 1688, 277
at LTC
https://tests.stockfishchess.org/tests/view/5f0836a559f6f0353289479c
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 25352 W: 3228 L: 3139 D: 18985
Ptnml(0-2): 175, 2350, 7549, 2415, 187
closes https://github.com/official-stockfish/Stockfish/pull/2804
Bench 4540940
2020-07-10 15:06:55 -06:00
|
|
|
{
|
2020-07-18 07:30:00 -06:00
|
|
|
// if transposition table doesn't have equal or more deep info write probCut data into it
|
Adjust penalty on refuted early quiet moves
This patch changes how previous early moves are penalized in case
search finds a best move. Here, the first quiet move that was not
a transposition table move is penalized.
passed STC
https://tests.stockfishchess.org/tests/view/5f51d839ba100690c5cc5f69
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 10088 W: 1150 L: 997 D: 7941
Ptnml(0-2): 41, 772, 3278, 899, 54
passed LTC
https://tests.stockfishchess.org/tests/view/5f51e435ba100690c5cc5f76
LLR: 2.93 (-2.94,2.94) {0.25,1.25}
Total: 30808 W: 1564 L: 1405 D: 27839
Ptnml(0-2): 19, 1245, 12717, 1404, 19
closes https://github.com/official-stockfish/Stockfish/pull/3106
bench 3983758
2020-09-04 06:53:59 -06:00
|
|
|
if ( !(ss->ttHit
|
Do not overwrite valuable TT data after probcut.
This patch allows an engine to write probcut data only in case
the probcut search depth is greater than transposition table depth.
passed STC
https://tests.stockfishchess.org/tests/view/5f0b52e959f6f035328949a6
LLR: 2.97 (-2.94,2.94) {-0.50,1.50}
Total: 52544 W: 10145 L: 9880 D: 32519
Ptnml(0-2): 853, 6097, 12121, 6334, 867
passed LTC
https://tests.stockfishchess.org/tests/view/5f0bd94c59f6f035328949f3
LLR: 2.93 (-2.94,2.94) {0.25,1.75}
Total: 49576 W: 6164 L: 5863 D: 37549
Ptnml(0-2): 297, 4371, 15218, 4538, 364
closes https://github.com/official-stockfish/Stockfish/pull/2815
bench 4578298
2020-07-13 11:30:58 -06:00
|
|
|
&& tte->depth() >= depth - 3
|
|
|
|
&& ttValue != VALUE_NONE))
|
|
|
|
tte->save(posKey, value_to_tt(value, ss->ply), ttPv,
|
|
|
|
BOUND_LOWER,
|
|
|
|
depth - 3, move, ss->staticEval);
|
2011-05-21 10:17:11 -06:00
|
|
|
return value;
|
Maximize usage of transposition table in probcut
Probcut is a heuristic that wasn't changed a lot in past years,
all attempts to change it using information / writing info to transposition table failed.
This patch has a number of differences that can be summarized as follows:
* For TT write/read we use depth - 3. Because probcut search is depth - 4 but we actually do the move prior to it so effectively we do depth - 3 search;
* In any case of depth of eval from transposition table being >= depth - 3 we either produce cutoff or refuse to even do probcut search, this is allowing us to write info of probcut to transposition table because we know that we wouldn't be overwriting some deeper data with our depth - 3 search - this is an important aspect of this patch;
* For some not really known reason this patch completely ignores tte->bound() - which was the case for previous patch that made probcut interact with TT, maybe 2) is the reason, although it's unproven.
A first version of this patch passed STC and LTC
passed STC
https://tests.stockfishchess.org/tests/view/5f05908a59f6f03532894613
LLR: 2.95 (-2.94,2.94) {-0.50,1.50}
Total: 95776 W: 18300 L: 17973 D: 59503
Ptnml(0-2): 1646, 10944, 22377, 11279, 1642
passed LTC
https://tests.stockfishchess.org/tests/view/5f06b54059f6f035328946bb
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 57128 W: 7266 L: 6938 D: 42924
Ptnml(0-2): 372, 5163, 17217, 5389, 423
However, an additional bugfix was needed to avoid checking a condition on ttMove if was not available. This passed non-regression bounds on top of the first version:
at STC
https://tests.stockfishchess.org/tests/view/5f080e5059f6f03532894766
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 14096 W: 2800 L: 2628 D: 8668
Ptnml(0-2): 225, 1620, 3238, 1688, 277
at LTC
https://tests.stockfishchess.org/tests/view/5f0836a559f6f0353289479c
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 25352 W: 3228 L: 3139 D: 18985
Ptnml(0-2): 175, 2350, 7549, 2415, 187
closes https://github.com/official-stockfish/Stockfish/pull/2804
Bench 4540940
2020-07-10 15:06:55 -06:00
|
|
|
}
|
2011-05-21 10:17:11 -06:00
|
|
|
}
|
Add / remove leaves from search tree ttPv
add if previous leaf is in search tree and we didn't find a counter move
else remove the position if the leaf is the last one in search tree.
STC : https://tests.stockfishchess.org/tests/view/5f49203c3def640786115314
LLR: 2.95 (-2.94,2.94) {-0.25,1.25}
Total: 29968 W: 3381 L: 3195 D: 23392
Ptnml(0-2): 146, 2432, 9671, 2560, 175
LTC : https://tests.stockfishchess.org/tests/view/5f494bea3def640786115336
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 84952 W: 4619 L: 4333 D: 76000
Ptnml(0-2): 86, 3765, 34481, 4065, 79
closes https://github.com/official-stockfish/Stockfish/pull/3075
Bench 3527337
2020-08-28 04:06:36 -06:00
|
|
|
ss->ttPv = ttPv;
|
2011-05-21 10:17:11 -06:00
|
|
|
}
|
Update parametes in classical evaluation.
Passed STC (NNUE=False):
https://tests.stockfishchess.org/tests/view/5f42edfe5089a564a10d84a0
LLR: 2.96 (-2.94,2.94) {-0.25,1.25}
Total: 13840 W: 2591 L: 2336 D: 8913
Ptnml(0-2): 194, 1453, 3387, 1676, 210
Passed LTC (NNUE=False):
https://tests.stockfishchess.org/tests/view/5f4369795089a564a10d84d8
LLR: 2.95 (-2.94,2.94) {0.25,1.25}
Total: 159744 W: 19430 L: 18850 D: 121464
Ptnml(0-2): 960, 14185, 49030, 14709, 988
closes https://github.com/official-stockfish/Stockfish/pull/3080
bench: 3736029
2020-08-30 04:58:05 -06:00
|
|
|
|
Remove razoring
has become ineffective now.
STC https://tests.stockfishchess.org/tests/view/5fe653403932f79192d3981a
LLR: 2.95 (-2.94,2.94) {-1.25,0.25}
Total: 63448 W: 5965 L: 5934 D: 51549
Ptnml(0-2): 230, 4738, 21769, 4745, 242
LTC https://tests.stockfishchess.org/tests/view/5fe6f0f03932f79192d39856
LLR: 2.93 (-2.94,2.94) {-0.75,0.25}
Total: 65368 W: 2485 L: 2459 D: 60424
Ptnml(0-2): 33, 2186, 28230, 2192, 43
closes https://github.com/official-stockfish/Stockfish/pull/3278
bench: 4493379
2020-12-26 05:48:04 -07:00
|
|
|
// Step 10. If the position is not in TT, decrease depth by 2
|
Reintroduce depth reduction
Reintroduce depth reduction if the position is not in TT.
STC https://tests.stockfishchess.org/tests/view/5f4652e85089a564a10d868c
LLR: 2.97 (-2.94,2.94) {-0.25,1.25}
Total: 40240 W: 4535 L: 4331 D: 31374
Ptnml(0-2): 215, 3276, 12969, 3410, 250
LTC https://tests.stockfishchess.org/tests/view/5f46ca5e5089a564a10d86f3
LLR: 2.93 (-2.94,2.94) {0.25,1.25}
Total: 63096 W: 3426 L: 3188 D: 56482
Ptnml(0-2): 51, 2798, 25645, 2970, 84
closes https://github.com/official-stockfish/Stockfish/pull/3072
bench: 3611906
2020-08-28 01:27:15 -06:00
|
|
|
if ( PvNode
|
|
|
|
&& depth >= 6
|
|
|
|
&& !ttMove)
|
|
|
|
depth -= 2;
|
2011-05-21 10:17:11 -06:00
|
|
|
|
2018-02-12 14:57:42 -07:00
|
|
|
moves_loop: // When in check, search starts from here
|
2010-10-16 03:01:45 -06:00
|
|
|
|
Introduce ProbCut for check evasions
The idea of this patch can be described as follows: if we are in check
and the transposition table move is a capture that returns a value
far above beta, we can assume that the opponent just blundered a piece
by giving check, and we return the transposition table value. This is
similar to the usual probCut logic for quiet moves, but with a different
threshold.
Passed STC
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 33440 W: 3056 L: 2891 D: 27493
Ptnml(0-2): 110, 2338, 11672, 2477, 123
https://tests.stockfishchess.org/tests/view/602cd1087f517a561bc49bda
Passed LTC
LLR: 2.98 (-2.94,2.94) {0.25,1.25}
Total: 10072 W: 401 L: 309 D: 9362
Ptnml(0-2): 2, 288, 4365, 378, 3
https://tests.stockfishchess.org/tests/view/602ceea57f517a561bc49bf0
The committed version has an additional fix to never return unproven wins
in the tablebase range or the mate range. This fix passed tests for non-
regression at STC and LTC:
STC:
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 26240 W: 2354 L: 2280 D: 21606
Ptnml(0-2): 85, 1763, 9372, 1793, 107
https://tests.stockfishchess.org/tests/view/602d86a87f517a561bc49c7a
LTC:
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 35304 W: 1299 L: 1256 D: 32749
Ptnml(0-2): 14, 1095, 15395, 1130, 18
https://tests.stockfishchess.org/tests/view/602d98d17f517a561bc49c83
Closes https://github.com/official-stockfish/Stockfish/pull/3362
Bench: 3830215
2021-02-20 14:48:08 -07:00
|
|
|
ttCapture = ttMove && pos.capture_or_promotion(ttMove);
|
|
|
|
|
|
|
|
// Step 11. A small Probcut idea, when we are in check
|
Tuning Search
This patch tunes constant in search.cpp
STC:
LLR: 2.94 (-2.94,2.94) <-0.50,2.50>
Total: 30648 W: 2580 L: 2410 D: 25658
Ptnml(0-2): 80, 1969, 11093, 2065, 117
https://tests.stockfishchess.org/tests/view/60a71d3cce8ea25a3ef03fae
LTC:
LLR: 2.95 (-2.94,2.94) <0.50,3.50>
Total: 52896 W: 1776 L: 1617 D: 49503
Ptnml(0-2): 13, 1462, 23347, 1605, 21
https://tests.stockfishchess.org/tests/view/60a794ddce8ea25a3ef0400a
closes https://github.com/official-stockfish/Stockfish/pull/3491
Bench: 4004731
2021-05-21 23:47:23 -06:00
|
|
|
probCutBeta = beta + 409;
|
Introduce ProbCut for check evasions
The idea of this patch can be described as follows: if we are in check
and the transposition table move is a capture that returns a value
far above beta, we can assume that the opponent just blundered a piece
by giving check, and we return the transposition table value. This is
similar to the usual probCut logic for quiet moves, but with a different
threshold.
Passed STC
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 33440 W: 3056 L: 2891 D: 27493
Ptnml(0-2): 110, 2338, 11672, 2477, 123
https://tests.stockfishchess.org/tests/view/602cd1087f517a561bc49bda
Passed LTC
LLR: 2.98 (-2.94,2.94) {0.25,1.25}
Total: 10072 W: 401 L: 309 D: 9362
Ptnml(0-2): 2, 288, 4365, 378, 3
https://tests.stockfishchess.org/tests/view/602ceea57f517a561bc49bf0
The committed version has an additional fix to never return unproven wins
in the tablebase range or the mate range. This fix passed tests for non-
regression at STC and LTC:
STC:
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 26240 W: 2354 L: 2280 D: 21606
Ptnml(0-2): 85, 1763, 9372, 1793, 107
https://tests.stockfishchess.org/tests/view/602d86a87f517a561bc49c7a
LTC:
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 35304 W: 1299 L: 1256 D: 32749
Ptnml(0-2): 14, 1095, 15395, 1130, 18
https://tests.stockfishchess.org/tests/view/602d98d17f517a561bc49c83
Closes https://github.com/official-stockfish/Stockfish/pull/3362
Bench: 3830215
2021-02-20 14:48:08 -07:00
|
|
|
if ( ss->inCheck
|
|
|
|
&& !PvNode
|
|
|
|
&& depth >= 4
|
|
|
|
&& ttCapture
|
|
|
|
&& (tte->bound() & BOUND_LOWER)
|
|
|
|
&& tte->depth() >= depth - 3
|
|
|
|
&& ttValue >= probCutBeta
|
|
|
|
&& abs(ttValue) <= VALUE_KNOWN_WIN
|
|
|
|
&& abs(beta) <= VALUE_KNOWN_WIN
|
|
|
|
)
|
|
|
|
return probCutBeta;
|
|
|
|
|
|
|
|
|
2019-02-27 13:25:12 -07:00
|
|
|
const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory,
|
2019-10-18 07:23:00 -06:00
|
|
|
nullptr , (ss-4)->continuationHistory,
|
|
|
|
nullptr , (ss-6)->continuationHistory };
|
2019-03-31 03:47:36 -06:00
|
|
|
|
2017-06-30 09:20:00 -06:00
|
|
|
Move countermove = thisThread->counterMoves[pos.piece_on(prevSq)][prevSq];
|
2013-05-19 13:32:52 -06:00
|
|
|
|
2018-04-28 22:48:18 -06:00
|
|
|
MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory,
|
Improve move order near the root
Current move histories are known to work well near the leaves, whilst at
higher depths they aren't very helpful. To address this problem this
patch introduces a table dedicated for what's happening at plies 0-3.
It's structured like mainHistory with ply index instead of color.
It get cleared with each new search and is filled during iterative
deepening at higher depths when recording successful quiet moves near
the root or traversing nodes which were in the principal variation
(ttPv).
Medium TC (20+0.2):
https://tests.stockfishchess.org/tests/view/5e4d358790a0a02810d096dc
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 100910 W: 16682 L: 16376 D: 67852
Ptnml(0-2): 1177, 10983, 25883, 11181, 1231
LTC:
https://tests.stockfishchess.org/tests/view/5e4e2cb790a0a02810d09714
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 80444 W: 10495 L: 10095 D: 59854
Ptnml(0-2): 551, 7479, 23803, 7797, 592
closes https://github.com/official-stockfish/Stockfish/pull/2557
Bench: 4705960
2020-02-21 06:01:59 -07:00
|
|
|
&thisThread->lowPlyHistory,
|
Introduce capture history pruning
This patch introduces a heuristic that is similar to countermove based pruning but for captures - capture history pruning. The idea is that we can (almost) safely prune really late captures with negative history if they don't give check so will most likely not produce some king-attacking tactic.
passed STC
https://tests.stockfishchess.org/tests/view/5e8c60d40ffd2be7f15e5470
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 23748 W: 4758 L: 4529 D: 14461
Ptnml(0-2): 421, 2712, 5400, 2899, 442
passed LTC
https://tests.stockfishchess.org/tests/view/5e8c72bf0ffd2be7f15e547f
LLR: 2.96 (-2.94,2.94) {0.25,1.75}
Total: 17330 W: 2415 L: 2190 D: 12725
Ptnml(0-2): 126, 1561, 5107, 1704, 167
closes https://github.com/official-stockfish/Stockfish/pull/2618
bench 4417023
2020-04-07 07:53:24 -06:00
|
|
|
&captureHistory,
|
2018-04-28 22:48:18 -06:00
|
|
|
contHist,
|
|
|
|
countermove,
|
Improve move order near the root
Current move histories are known to work well near the leaves, whilst at
higher depths they aren't very helpful. To address this problem this
patch introduces a table dedicated for what's happening at plies 0-3.
It's structured like mainHistory with ply index instead of color.
It get cleared with each new search and is filled during iterative
deepening at higher depths when recording successful quiet moves near
the root or traversing nodes which were in the principal variation
(ttPv).
Medium TC (20+0.2):
https://tests.stockfishchess.org/tests/view/5e4d358790a0a02810d096dc
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 100910 W: 16682 L: 16376 D: 67852
Ptnml(0-2): 1177, 10983, 25883, 11181, 1231
LTC:
https://tests.stockfishchess.org/tests/view/5e4e2cb790a0a02810d09714
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 80444 W: 10495 L: 10095 D: 59854
Ptnml(0-2): 551, 7479, 23803, 7797, 592
closes https://github.com/official-stockfish/Stockfish/pull/2557
Bench: 4705960
2020-02-21 06:01:59 -07:00
|
|
|
ss->killers,
|
Use lowply-history also on low depths
STC:
https://tests.stockfishchess.org/tests/view/5ed75078f29b40b0fc95a8b9
LLR: 2.93 (-2.94,2.94) {-0.50,1.50}
Total: 73928 W: 14301 L: 14005 D: 45622
Ptnml(0-2): 1243, 8572, 17096, 8752, 1301
LTC:
https://tests.stockfishchess.org/tests/view/5ed895e0f29b40b0fc95a976
LLR: 2.93 (-2.94,2.94) {0.25,1.75}
Total: 154848 W: 19684 L: 19074 D: 116090
Ptnml(0-2): 1048, 14108, 46627, 14468, 1173
closes https://github.com/official-stockfish/Stockfish/pull/2718
bench: 4582693
2020-06-06 04:56:38 -06:00
|
|
|
ss->ply);
|
2013-08-09 00:21:55 -06:00
|
|
|
|
2019-10-18 07:23:00 -06:00
|
|
|
value = bestValue;
|
Singular quiet LMR
If ttMove is a capture and had a singular extension, it is probably the best move.
No need to make a decrease of LMR on other moves.
STC
LLR: 2.96 (-2.94,2.94) {-0.50,1.50}
Total: 41968 W: 8170 L: 7918 D: 25880
Ptnml(0-2): 733, 4770, 9726, 5022, 733
https://tests.stockfishchess.org/tests/view/5ed6b666f29b40b0fc95a884
LTC
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 71376 W: 9200 L: 8827 D: 53349
Ptnml(0-2): 486, 6544, 21342, 6743, 573
https://tests.stockfishchess.org/tests/view/5ed7578bf29b40b0fc95a8c9
closes https://github.com/official-stockfish/Stockfish/pull/2713
Bench: 4733799
2020-06-02 14:27:11 -06:00
|
|
|
singularQuietLMR = moveCountPruning = false;
|
2010-10-16 03:01:45 -06:00
|
|
|
|
Cleanup of likelyFailLow logic
This patch broadens and simplifies definition of PvNode that is likely to fail low.
New definition can be described as following "If node was already researched
at depth >= current depth and failed low there" which is more logical than the
previous version and takes less space + allows to not recompute it every time during move loop.
Passed simplification STC
https://tests.stockfishchess.org/tests/view/609148bf95e7f1852abd2e82
LLR: 2.93 (-2.94,2.94) <-2.50,0.50>
Total: 20128 W: 1865 L: 1751 D: 16512
Ptnml(0-2): 63, 1334, 7165, 1430, 72
Passed simplification LTC
https://tests.stockfishchess.org/tests/view/6091691295e7f1852abd2e8b
LLR: 2.94 (-2.94,2.94) <-2.50,0.50>
Total: 95128 W: 3498 L: 3481 D: 88149
Ptnml(0-2): 41, 2956, 41549, 2981, 37
closes https://github.com/official-stockfish/Stockfish/pull/3455
Bench: 3933037
2021-05-05 10:03:20 -06:00
|
|
|
// Indicate PvNodes that will probably fail low if the node was searched
|
|
|
|
// at a depth equal or greater than the current depth, and the result of this search was a fail low.
|
|
|
|
bool likelyFailLow = PvNode
|
|
|
|
&& ttMove
|
|
|
|
&& (tte->bound() & BOUND_UPPER)
|
|
|
|
&& tte->depth() >= depth;
|
|
|
|
|
Introduce ProbCut for check evasions
The idea of this patch can be described as follows: if we are in check
and the transposition table move is a capture that returns a value
far above beta, we can assume that the opponent just blundered a piece
by giving check, and we return the transposition table value. This is
similar to the usual probCut logic for quiet moves, but with a different
threshold.
Passed STC
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 33440 W: 3056 L: 2891 D: 27493
Ptnml(0-2): 110, 2338, 11672, 2477, 123
https://tests.stockfishchess.org/tests/view/602cd1087f517a561bc49bda
Passed LTC
LLR: 2.98 (-2.94,2.94) {0.25,1.25}
Total: 10072 W: 401 L: 309 D: 9362
Ptnml(0-2): 2, 288, 4365, 378, 3
https://tests.stockfishchess.org/tests/view/602ceea57f517a561bc49bf0
The committed version has an additional fix to never return unproven wins
in the tablebase range or the mate range. This fix passed tests for non-
regression at STC and LTC:
STC:
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 26240 W: 2354 L: 2280 D: 21606
Ptnml(0-2): 85, 1763, 9372, 1793, 107
https://tests.stockfishchess.org/tests/view/602d86a87f517a561bc49c7a
LTC:
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 35304 W: 1299 L: 1256 D: 32749
Ptnml(0-2): 14, 1095, 15395, 1130, 18
https://tests.stockfishchess.org/tests/view/602d98d17f517a561bc49c83
Closes https://github.com/official-stockfish/Stockfish/pull/3362
Bench: 3830215
2021-02-20 14:48:08 -07:00
|
|
|
// Step 12. Loop through all pseudo-legal moves until no moves remain
|
2018-02-12 14:57:42 -07:00
|
|
|
// or a beta cutoff occurs.
|
2019-02-27 05:36:48 -07:00
|
|
|
while ((move = mp.next_move(moveCountPruning)) != MOVE_NONE)
|
2008-09-06 10:25:58 -06:00
|
|
|
{
|
2011-10-03 02:56:49 -06:00
|
|
|
assert(is_ok(move));
|
2011-01-16 15:40:06 -07:00
|
|
|
|
2011-05-28 03:35:52 -06:00
|
|
|
if (move == excludedMove)
|
|
|
|
continue;
|
|
|
|
|
2018-02-04 13:42:56 -07:00
|
|
|
// At root obey the "searchmoves" option and skip moves not listed in Root
|
|
|
|
// Move List. As a consequence any illegal move is also skipped. In MultiPV
|
2018-04-18 10:38:38 -06:00
|
|
|
// mode we also skip PV moves which have been already searched and those
|
|
|
|
// of lower "TB rank" if we are in a TB root position.
|
2018-06-02 09:41:37 -06:00
|
|
|
if (rootNode && !std::count(thisThread->rootMoves.begin() + thisThread->pvIdx,
|
|
|
|
thisThread->rootMoves.begin() + thisThread->pvLast, move))
|
2018-02-04 13:42:56 -07:00
|
|
|
continue;
|
2011-07-31 06:18:52 -06:00
|
|
|
|
Do move legality check before pruning.
This alllows to simplify the code because the move counter haven't to be
decremented later if a move isn't legal. As a side effect now illegal
pruned moves doesn't included anymore in move counter. So slightly less
pruning and reductions are done.
STC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 111016 W: 21106 L: 21077 D: 68833
Ptnml(0-2): 1830, 13083, 25736, 12946, 1913
https://tests.stockfishchess.org/tests/view/5f28816fa5abc164f05e4c26
LTC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 39264 W: 4909 L: 4843 D: 29512
Ptnml(0-2): 263, 3601, 11854, 3635, 279
https://tests.stockfishchess.org/tests/view/5f297902a5abc164f05e4c8e
closes https://github.com/official-stockfish/Stockfish/pull/2906
Bench: 4390086
2020-08-05 01:29:27 -06:00
|
|
|
// Check for legality
|
|
|
|
if (!rootNode && !pos.legal(move))
|
|
|
|
continue;
|
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
ss->moveCount = ++moveCount;
|
2012-09-29 09:41:53 -06:00
|
|
|
|
2016-01-18 15:20:16 -07:00
|
|
|
if (rootNode && thisThread == Threads.main() && Time.elapsed() > 3000)
|
2019-09-28 14:27:23 -06:00
|
|
|
sync_cout << "info depth " << depth
|
2015-12-09 00:07:34 -07:00
|
|
|
<< " currmove " << UCI::move(move, pos.is_chess960())
|
2018-06-02 09:41:37 -06:00
|
|
|
<< " currmovenumber " << moveCount + thisThread->pvIdx << sync_endl;
|
2014-11-12 14:13:55 -07:00
|
|
|
if (PvNode)
|
2015-01-18 00:00:50 -07:00
|
|
|
(ss+1)->pv = nullptr;
|
2014-11-12 14:13:55 -07:00
|
|
|
|
2019-09-28 14:27:23 -06:00
|
|
|
extension = 0;
|
2013-09-28 06:43:50 -06:00
|
|
|
captureOrPromotion = pos.capture_or_promotion(move);
|
2017-08-09 19:43:30 -06:00
|
|
|
movedPiece = pos.moved_piece(move);
|
2019-03-31 02:44:55 -06:00
|
|
|
givesCheck = pos.gives_check(move);
|
2014-02-08 05:21:50 -07:00
|
|
|
|
2019-11-12 10:36:12 -07:00
|
|
|
// Calculate new depth for this move
|
|
|
|
newDepth = depth - 1;
|
|
|
|
|
Introduce ProbCut for check evasions
The idea of this patch can be described as follows: if we are in check
and the transposition table move is a capture that returns a value
far above beta, we can assume that the opponent just blundered a piece
by giving check, and we return the transposition table value. This is
similar to the usual probCut logic for quiet moves, but with a different
threshold.
Passed STC
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 33440 W: 3056 L: 2891 D: 27493
Ptnml(0-2): 110, 2338, 11672, 2477, 123
https://tests.stockfishchess.org/tests/view/602cd1087f517a561bc49bda
Passed LTC
LLR: 2.98 (-2.94,2.94) {0.25,1.25}
Total: 10072 W: 401 L: 309 D: 9362
Ptnml(0-2): 2, 288, 4365, 378, 3
https://tests.stockfishchess.org/tests/view/602ceea57f517a561bc49bf0
The committed version has an additional fix to never return unproven wins
in the tablebase range or the mate range. This fix passed tests for non-
regression at STC and LTC:
STC:
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 26240 W: 2354 L: 2280 D: 21606
Ptnml(0-2): 85, 1763, 9372, 1793, 107
https://tests.stockfishchess.org/tests/view/602d86a87f517a561bc49c7a
LTC:
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 35304 W: 1299 L: 1256 D: 32749
Ptnml(0-2): 14, 1095, 15395, 1130, 18
https://tests.stockfishchess.org/tests/view/602d98d17f517a561bc49c83
Closes https://github.com/official-stockfish/Stockfish/pull/3362
Bench: 3830215
2021-02-20 14:48:08 -07:00
|
|
|
// Step 13. Pruning at shallow depth (~200 Elo)
|
2019-11-12 10:36:12 -07:00
|
|
|
if ( !rootNode
|
|
|
|
&& pos.non_pawn_material(us)
|
Fix for incorrect VALUE_MATE_IN_MAX_PLY usage.
Fixes #2533, fixes #2543, fixes #2423.
the code that prevents false mate announcements depending on the TT
state (GHI), incorrectly used VALUE_MATE_IN_MAX_PLY. The latter
constant, however, also includes, counterintuitively, the TB win range.
This patch fixes that, by restoring the behavior for TB win scores,
while retaining the false mate correctness, and improving the mate
finding ability. In particular
no alse mates are announced with the poisened hash testcase
```
position fen 8/8/8/3k4/8/8/6K1/7R w - - 0 1
go depth 40
position fen 8/8/8/3k4/8/8/6K1/7R w - - 76 1
go depth 20
ucinewgame
```
mates are found with the testcases reported in #2543
```
position fen 4k3/3pp3/8/8/8/8/2PPP3/4K3 w - - 0 1
setoption name Hash value 1024
go depth 55
ucinewgame
```
and
```
position fen 4k3/4p3/8/8/8/8/3PP3/4K3 w - - 0 1
setoption name Hash value 1024
go depth 45
ucinewgame
```
furthermore, on the mate finding benchmark (ChestUCI_23102018.epd),
performance improves over master, roughly reaching performance with the
false mate protection reverted
```
Analyzing 6566 mate positions for best and found mates:
----------------best ---------------found
nodes master revert fixed master revert fixed
16000000 4233 4236 4235 5200 5201 5199
32000000 4583 4585 4585 5417 5424 5418
64000000 4852 4853 4855 5575 5584 5579
128000000 5071 5068 5066 5710 5720 5716
256000000 5280 5282 5279 5819 5827 5826
512000000 5471 5468 5468 5919 5935 5932
```
On a testcase with TB enabled, progress is made consistently, contrary
to master
```
setoption name SyzygyPath value ../../../syzygy/3-4-5/
setoption name Hash value 2048
position fen 1R6/3k4/8/K2p4/4n3/2P5/8/8 w - - 0 1
go depth 58
ucinewgame
```
The PR (prior to a rewrite for clarity)
passed STC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 65405 W: 12454 L: 12384 D: 40567
Ptnml(0-2): 920, 7256, 16285, 7286, 944
http://tests.stockfishchess.org/tests/view/5e441a3be70d848499f63d15
passed LTC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 27096 W: 3477 L: 3413 D: 20206
Ptnml(0-2): 128, 2215, 8776, 2292, 122
http://tests.stockfishchess.org/tests/view/5e44e277e70d848499f63d63
The incorrectly named VALUE_MATE_IN_MAX_PLY and VALUE_MATED_IN_MAX_PLY
were renamed into VALUE_TB_WIN_IN_MAX_PLY and VALUE_TB_LOSS_IN_MAX_PLY,
and correclty defined VALUE_MATE_IN_MAX_PLY and VALUE_MATED_IN_MAX_PLY
were introduced.
One further (corner case) mistake using these constants was fixed (go
mate X), which could lead to a premature return if X > MAX_PLY / 2,
but TB were present.
Thanks to @svivanov72 for one of the reports and help fixing the issue.
closes https://github.com/official-stockfish/Stockfish/pull/2552
Bench: 4932981
2020-02-11 12:42:32 -07:00
|
|
|
&& bestValue > VALUE_TB_LOSS_IN_MAX_PLY)
|
2019-11-12 10:36:12 -07:00
|
|
|
{
|
|
|
|
// Skip quiet moves if movecount exceeds our FutilityMoveCount threshold
|
|
|
|
moveCountPruning = moveCount >= futility_move_count(improving, depth);
|
|
|
|
|
Introduce capture history pruning
This patch introduces a heuristic that is similar to countermove based pruning but for captures - capture history pruning. The idea is that we can (almost) safely prune really late captures with negative history if they don't give check so will most likely not produce some king-attacking tactic.
passed STC
https://tests.stockfishchess.org/tests/view/5e8c60d40ffd2be7f15e5470
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 23748 W: 4758 L: 4529 D: 14461
Ptnml(0-2): 421, 2712, 5400, 2899, 442
passed LTC
https://tests.stockfishchess.org/tests/view/5e8c72bf0ffd2be7f15e547f
LLR: 2.96 (-2.94,2.94) {0.25,1.75}
Total: 17330 W: 2415 L: 2190 D: 12725
Ptnml(0-2): 126, 1561, 5107, 1704, 167
closes https://github.com/official-stockfish/Stockfish/pull/2618
bench 4417023
2020-04-07 07:53:24 -06:00
|
|
|
// Reduced depth of the next LMR search
|
|
|
|
int lmrDepth = std::max(newDepth - reduction(improving, depth, moveCount), 0);
|
|
|
|
|
2021-01-01 02:59:35 -07:00
|
|
|
if ( captureOrPromotion
|
|
|
|
|| givesCheck)
|
|
|
|
{
|
|
|
|
// Capture history based pruning when the move doesn't give check
|
|
|
|
if ( !givesCheck
|
|
|
|
&& lmrDepth < 1
|
|
|
|
&& captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] < 0)
|
|
|
|
continue;
|
|
|
|
|
|
|
|
// SEE based pruning
|
|
|
|
if (!pos.see_ge(move, Value(-218) * depth)) // (~25 Elo)
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
else
|
2019-11-12 10:36:12 -07:00
|
|
|
{
|
2021-05-17 01:13:34 -06:00
|
|
|
// Continuation history based pruning (~20 Elo)
|
Do more continuation history based pruning
This patch increases lmrDepth threshold for continuation history based pruning in search.
This part of code for a long time was known to be really TC sensitive - decreasing
this threshold easily passed lower time controls but failed badly at LTC,
on the other hand it increase was part of a tuning that resulted
in being negative at STC but was +12 elo at 180+1.8.
After recent simplification of special conditions that sometimes
increase it from 4 to 5 it was logical to overall test at longer
time controls if 5 is better than 4 with deeper searches.
reduces strenght on STC
https://tests.stockfishchess.org/tests/view/60a3a8bbce8ea25a3ef03c74
ELO: -2.57 +-2.0 (95%) LOS: 0.6%
Total: 20000 W: 1820 L: 1968 D: 16212
Ptnml(0-2): 68, 1582, 6836, 1458, 56
Passed LTC with STC bounds
https://tests.stockfishchess.org/tests/view/60a027395085663412d090ce
LLR: 2.93 (-2.94,2.94) <-0.50,2.50>
Total: 175256 W: 6774 L: 6548 D: 161934
Ptnml(0-2): 91, 5808, 75604, 6034, 91
Passed VLTC with LTC bounds
https://tests.stockfishchess.org/tests/view/60a2bccce229097940a037a7
LLR: 2.96 (-2.94,2.94) <0.50,3.50>
Total: 65736 W: 1224 L: 1092 D: 63420
Ptnml(0-2): 5, 1012, 30706, 1136, 9
closes https://github.com/official-stockfish/Stockfish/pull/3473
bench 3689330
2021-05-18 01:02:20 -06:00
|
|
|
if ( lmrDepth < 5
|
2019-11-12 10:36:12 -07:00
|
|
|
&& (*contHist[0])[movedPiece][to_sq(move)] < CounterMovePruneThreshold
|
|
|
|
&& (*contHist[1])[movedPiece][to_sq(move)] < CounterMovePruneThreshold)
|
|
|
|
continue;
|
|
|
|
|
2020-01-09 19:02:09 -07:00
|
|
|
// Futility pruning: parent node (~5 Elo)
|
Assorted search parameter tune
STC https://tests.stockfishchess.org/tests/view/5f31219090816720665374ec
LLR: 2.96 (-2.94,2.94) {-0.50,1.50}
Total: 3376 W: 487 L: 359 D: 2530
Ptnml(0-2): 17, 253, 1042, 337, 39
LTC https://tests.stockfishchess.org/tests/view/5f3127f79081672066537502
LLR: 2.93 (-2.94,2.94) {0.25,1.75}
Total: 8360 W: 581 L: 475 D: 7304
Ptnml(0-2): 11, 407, 3238, 513, 11
closes https://github.com/official-stockfish/Stockfish/pull/2971
bench: 4733874
2020-08-10 07:38:44 -06:00
|
|
|
if ( lmrDepth < 7
|
continuation histories when in check
If in check, don't write to continuation histories ss-4, ss-6.
Adding inCheck to the stack was needed, and might be useful for
future patches.
Passed STC:
https://tests.stockfishchess.org/tests/view/5e9ee24acaaff5d60a50b812
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 61774 W: 11725 L: 11449 D: 38600
Ptnml(0-2): 971, 7211, 14322, 7337, 1046
Passed LTC:
https://tests.stockfishchess.org/tests/view/5e9eecb7caaff5d60a50b831
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 250822 W: 32067 L: 31179 D: 187576
Ptnml(0-2): 1745, 23126, 74824, 23928, 1788
closes https://github.com/official-stockfish/Stockfish/pull/2645
bench: 4808463
2020-04-21 12:55:41 -06:00
|
|
|
&& !ss->inCheck
|
Search Parameters Tuning
A simple tuning on search.cpp.
based SPSA test:
https://tests.stockfishchess.org/tests/view/601f2a787f517a561bc493cd
passed STC:
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 117840 W: 10796 L: 10508 D: 96536
Ptnml(0-2): 422, 8381, 41041, 8639, 437
https://tests.stockfishchess.org/tests/view/602144c37f517a561bc494ae
passed LTC:
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 25024 W: 972 L: 847 D: 23205
Ptnml(0-2): 7, 767, 10847, 876, 15
https://tests.stockfishchess.org/tests/view/602156877f517a561bc494be
closes https://github.com/official-stockfish/Stockfish/pull/3340
Bench: 3974098
2021-02-04 17:50:22 -07:00
|
|
|
&& ss->staticEval + 174 + 157 * lmrDepth <= alpha
|
Simplify futility pruning parent node
only continuation histories seem needed for this purpose.
STC:
http://tests.stockfishchess.org/tests/view/5e6b88dfe42a5c3b3ca2e4ab
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 113356 W: 21725 L: 21696 D: 69935
Ptnml(0-2): 1999, 13255, 26163, 13240, 2021
LTC:
http://tests.stockfishchess.org/tests/view/5e6babbfe42a5c3b3ca2e4c2
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 22164 W: 2917 L: 2821 D: 16426
Ptnml(0-2): 173, 2040, 6548, 2160, 161
closes https://github.com/official-stockfish/Stockfish/pull/2583
bench: 4839496
2020-03-13 12:29:36 -06:00
|
|
|
&& (*contHist[0])[movedPiece][to_sq(move)]
|
Tweak futility pruning
Exclude moves with a good history total from futility pruning. This adds
a condition for quiet futility pruning: history total has to be low.
STC:
LLR: 2.94 (-2.94,2.94) {-1.00,3.00}
Total: 20095 W: 4503 L: 4342 D: 11250
Ptnml(0-2): 362, 2380, 4422, 2486, 388
http://tests.stockfishchess.org/tests/view/5e0d7c5387585b1706b68370
LTC:
LLR: 2.94 (-2.94,2.94) {0.00,2.00}
Total: 53016 W: 8587 L: 8302 D: 36127
Ptnml(0-2): 353, 5397, 14751, 5545, 423
http://tests.stockfishchess.org/tests/view/5e0e30d062fb773bb7047e95
Closes https://github.com/official-stockfish/Stockfish/pull/2472
Bench: 5215200
2020-01-03 03:49:25 -07:00
|
|
|
+ (*contHist[1])[movedPiece][to_sq(move)]
|
Adjust history threshold for quiet moves futility pruning
This patch adjusts the threshold for futility pruning of quiet moves
using the continuation history array contHist[5], in the same way as
it is used in movepicker.
passed STC:
https://tests.stockfishchess.org/tests/view/5ee3f88bca6c451633a9959f
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 55984 W: 10822 L: 10552 D: 34610
Ptnml(0-2): 952, 6435, 12941, 6719, 945
passed LTC:
https://tests.stockfishchess.org/tests/view/5ee4186dca6c451633a995cf
LLR: 2.96 (-2.94,2.94) {0.25,1.75}
Total: 41712 W: 5402 L: 5114 D: 31196
Ptnml(0-2): 293, 3766, 12469, 4016, 312
closes https://github.com/official-stockfish/Stockfish/pull/2734
Bench: 4715960
2020-06-12 20:03:59 -06:00
|
|
|
+ (*contHist[3])[movedPiece][to_sq(move)]
|
Tune search parameters (with Unai Corzo)
The values used in this patch are taken from a SPSA parameter tuning session
originated by Unai Corzo (@unaiic), but the final difference of his tune was
multiplied x2 by hand. Most of the credits should go to him :-)
STC:
https://tests.stockfishchess.org/tests/view/602f03d07f517a561bc49d40
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 67664 W: 6252 L: 6035 D: 55377
Ptnml(0-2): 256, 4799, 23527, 4972, 278
LTC:
https://tests.stockfishchess.org/tests/view/602f41697f517a561bc49d5a
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 26256 W: 1034 L: 906 D: 24316
Ptnml(0-2): 10, 804, 11377, 922, 15
Closes https://github.com/official-stockfish/Stockfish/pull/3363
Bench: 3957653
2021-02-19 00:32:12 -07:00
|
|
|
+ (*contHist[5])[movedPiece][to_sq(move)] / 3 < 28255)
|
2019-11-12 10:36:12 -07:00
|
|
|
continue;
|
|
|
|
|
2020-01-09 19:02:09 -07:00
|
|
|
// Prune moves with negative SEE (~20 Elo)
|
Assorted search and eval parameter tune
Search and eval parameter tune.
STC https://tests.stockfishchess.org/tests/view/5fba850a67cbf42301d6b07d
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 24312 W: 2388 L: 2228 D: 19696
Ptnml(0-2): 85, 1800, 8241, 1930, 100
LTC https://tests.stockfishchess.org/tests/view/5fbad5ea67cbf42301d6b0fa
LLR: 2.95 (-2.94,2.94) {0.25,1.25}
Total: 88376 W: 3619 L: 3351 D: 81406
Ptnml(0-2): 56, 2977, 37849, 3255, 51
closes https://github.com/official-stockfish/Stockfish/pull/3232
bench: 3600361
2020-11-24 09:06:30 -07:00
|
|
|
if (!pos.see_ge(move, Value(-(30 - std::min(lmrDepth, 18)) * lmrDepth * lmrDepth)))
|
2019-11-12 10:36:12 -07:00
|
|
|
continue;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
Introduce ProbCut for check evasions
The idea of this patch can be described as follows: if we are in check
and the transposition table move is a capture that returns a value
far above beta, we can assume that the opponent just blundered a piece
by giving check, and we return the transposition table value. This is
similar to the usual probCut logic for quiet moves, but with a different
threshold.
Passed STC
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 33440 W: 3056 L: 2891 D: 27493
Ptnml(0-2): 110, 2338, 11672, 2477, 123
https://tests.stockfishchess.org/tests/view/602cd1087f517a561bc49bda
Passed LTC
LLR: 2.98 (-2.94,2.94) {0.25,1.25}
Total: 10072 W: 401 L: 309 D: 9362
Ptnml(0-2): 2, 288, 4365, 378, 3
https://tests.stockfishchess.org/tests/view/602ceea57f517a561bc49bf0
The committed version has an additional fix to never return unproven wins
in the tablebase range or the mate range. This fix passed tests for non-
regression at STC and LTC:
STC:
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 26240 W: 2354 L: 2280 D: 21606
Ptnml(0-2): 85, 1763, 9372, 1793, 107
https://tests.stockfishchess.org/tests/view/602d86a87f517a561bc49c7a
LTC:
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 35304 W: 1299 L: 1256 D: 32749
Ptnml(0-2): 14, 1095, 15395, 1130, 18
https://tests.stockfishchess.org/tests/view/602d98d17f517a561bc49c83
Closes https://github.com/official-stockfish/Stockfish/pull/3362
Bench: 3830215
2021-02-20 14:48:08 -07:00
|
|
|
// Step 14. Extensions (~75 Elo)
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2020-01-09 19:02:09 -07:00
|
|
|
// Singular extension search (~70 Elo). If all moves but one fail low on a
|
2018-04-02 16:13:35 -06:00
|
|
|
// search of (alpha-s, beta-s), and just one fails high on (alpha, beta),
|
|
|
|
// then that move is singular and should be extended. To verify this we do
|
2018-09-21 15:18:46 -06:00
|
|
|
// a reduced search on all the other moves but the ttMove and if the
|
Remove late irreversible move extension
We simplify away the late irreversible move extension, which
does not seem to be necessary in the current master.
STC
LLR: 2.93 (-2.94,2.94) {-1.50,0.50}
Total: 38584 W: 7464 L: 7342 D: 23778
Ptnml(0-2): 581, 4328, 9365, 4424, 594
https://tests.stockfishchess.org/tests/view/5f1c9669c09435d870cb9de9
LTC
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 27840 W: 3417 L: 3353 D: 21070
Ptnml(0-2): 120, 2315, 8994, 2363, 128
https://tests.stockfishchess.org/tests/view/5f1d2e22c09435d870cb9e21
closes https://github.com/official-stockfish/Stockfish/pull/2836
bench: 4829420
2020-07-25 14:30:05 -06:00
|
|
|
// result is lower than ttValue minus a margin, then we will extend the ttMove.
|
Singular extension search tweak
Tweak depth.
STC https://tests.stockfishchess.org/tests/view/5f2d22ec61e3b6af64881f40
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 17984 W: 2603 L: 2441 D: 12940
Ptnml(0-2): 133, 1751, 5094, 1849, 165
LTC https://tests.stockfishchess.org/tests/view/5f2d5a6a61e3b6af64881f7f
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 85808 W: 5956 L: 5621 D: 74231
Ptnml(0-2): 149, 4748, 32785, 5063, 159
closes https://github.com/official-stockfish/Stockfish/pull/2950
fixes two README.md typos:
fixes https://github.com/official-stockfish/Stockfish/issues/2932
bench: 4022669
2020-08-08 14:03:37 -06:00
|
|
|
if ( depth >= 7
|
2012-04-28 04:08:10 -06:00
|
|
|
&& move == ttMove
|
2018-04-02 16:13:35 -06:00
|
|
|
&& !rootNode
|
2018-12-11 05:47:56 -07:00
|
|
|
&& !excludedMove // Avoid recursive singular search
|
2019-03-31 04:02:19 -06:00
|
|
|
/* && ttValue != VALUE_NONE Already implicit in the next condition */
|
2019-03-09 05:24:26 -07:00
|
|
|
&& abs(ttValue) < VALUE_KNOWN_WIN
|
2018-04-02 16:13:35 -06:00
|
|
|
&& (tte->bound() & BOUND_LOWER)
|
2020-08-08 04:07:07 -06:00
|
|
|
&& tte->depth() >= depth - 3)
|
2009-11-21 06:22:52 -07:00
|
|
|
{
|
Movecount pruning reduction logic
This patch refines search reduction logic in case the position is not a former PV node and is pruned based on move count.
passed STC
https://tests.stockfishchess.org/tests/view/5e8092bde42a5c3b3ca2ed35
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 78848 W: 15480 L: 15170 D: 48198
Ptnml(0-2): 1406, 9310, 17773, 9438, 1497
passed LTC
https://tests.stockfishchess.org/tests/view/5e80bb13e42a5c3b3ca2ed4b
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 86596 W: 11451 L: 11033 D: 64112
Ptnml(0-2): 624, 7993, 25687, 8329, 665
closes https://github.com/official-stockfish/Stockfish/pull/2605
Bench: 5138771
2020-03-29 22:52:42 -06:00
|
|
|
Value singularBeta = ttValue - ((formerPv + 4) * depth) / 2;
|
|
|
|
Depth singularDepth = (depth - 1 + 3 * formerPv) / 2;
|
2021-03-19 12:43:25 -06:00
|
|
|
|
2012-07-14 05:18:14 -06:00
|
|
|
ss->excludedMove = move;
|
Adjust singular extension search depth
This patch applies a different singular extension search logic in case the position is ttPv && !PvNode.
It changes the depth of this search, higher for this types of nodes, and lower for other nodes.
passed STC
http://tests.stockfishchess.org/tests/view/5e72bbaae42a5c3b3ca2e75e
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 12692 W: 2608 L: 2389 D: 7695
Ptnml(0-2): 238, 1414, 2839, 1601, 254
passed LTC
http://tests.stockfishchess.org/tests/view/5e731c07e42a5c3b3ca2e770
LLR: 2.96 (-2.94,2.94) {0.25,1.75}
Total: 145716 W: 19218 L: 18626 D: 107872
Ptnml(0-2): 1100, 13605, 42899, 14111, 1143
closes https://github.com/official-stockfish/Stockfish/pull/2590
Bench: 5398277
2020-03-20 03:12:56 -06:00
|
|
|
value = search<NonPV>(pos, ss, singularBeta - 1, singularBeta, singularDepth, cutNode);
|
2012-07-14 05:18:14 -06:00
|
|
|
ss->excludedMove = MOVE_NONE;
|
|
|
|
|
2019-01-05 13:53:21 -07:00
|
|
|
if (value < singularBeta)
|
2019-05-02 11:36:25 -06:00
|
|
|
{
|
2019-09-28 14:27:23 -06:00
|
|
|
extension = 1;
|
Singular quiet LMR
If ttMove is a capture and had a singular extension, it is probably the best move.
No need to make a decrease of LMR on other moves.
STC
LLR: 2.96 (-2.94,2.94) {-0.50,1.50}
Total: 41968 W: 8170 L: 7918 D: 25880
Ptnml(0-2): 733, 4770, 9726, 5022, 733
https://tests.stockfishchess.org/tests/view/5ed6b666f29b40b0fc95a884
LTC
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 71376 W: 9200 L: 8827 D: 53349
Ptnml(0-2): 486, 6544, 21342, 6743, 573
https://tests.stockfishchess.org/tests/view/5ed7578bf29b40b0fc95a8c9
closes https://github.com/official-stockfish/Stockfish/pull/2713
Bench: 4733799
2020-06-02 14:27:11 -06:00
|
|
|
singularQuietLMR = !ttCapture;
|
Tuning Search
This patch tunes constant in search.cpp
STC:
LLR: 2.94 (-2.94,2.94) <-0.50,2.50>
Total: 30648 W: 2580 L: 2410 D: 25658
Ptnml(0-2): 80, 1969, 11093, 2065, 117
https://tests.stockfishchess.org/tests/view/60a71d3cce8ea25a3ef03fae
LTC:
LLR: 2.95 (-2.94,2.94) <0.50,3.50>
Total: 52896 W: 1776 L: 1617 D: 49503
Ptnml(0-2): 13, 1462, 23347, 1605, 21
https://tests.stockfishchess.org/tests/view/60a794ddce8ea25a3ef0400a
closes https://github.com/official-stockfish/Stockfish/pull/3491
Bench: 4004731
2021-05-21 23:47:23 -06:00
|
|
|
if (!PvNode && value < singularBeta - 93)
|
More extensions if SE search is very low.
More extensions for non-PV nodes if value from singular extension search is significantly below singularBeta.
Passed STC:
LLR: 2.97 (-2.94,2.94) <-0.50,2.50>
Total: 25064 W: 2334 L: 2162 D: 20568
Ptnml(0-2): 82, 1720, 8768, 1868, 94
https://tests.stockfishchess.org/tests/view/6084ba7995e7f1852abd27e3
Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,3.50>
Total: 67136 W: 2644 L: 2450 D: 62042
Ptnml(0-2): 46, 2134, 28990, 2376, 22
https://tests.stockfishchess.org/tests/view/6084d79195e7f1852abd27ee
closes https://github.com/official-stockfish/Stockfish/pull/3445
Bench: 4075325
2021-04-24 18:37:47 -06:00
|
|
|
extension = 2;
|
2019-05-02 11:36:25 -06:00
|
|
|
}
|
2019-01-05 13:53:21 -07:00
|
|
|
|
|
|
|
// Multi-cut pruning
|
|
|
|
// Our ttMove is assumed to fail high, and now we failed high also on a reduced
|
|
|
|
// search without the ttMove. So we assume this expected Cut-node is not singular,
|
Change multi-cut pruning condition
Use comparison of eval with beta to predict potential cutNodes. This
allows multi-cut pruning to also prune possibly mislabeled Pv and NonPv
nodes.
STC:
LLR: 2.95 (-2.94,2.94) [0.50,4.50]
Total: 54305 W: 12302 L: 11867 D: 30136
http://tests.stockfishchess.org/tests/view/5d048ba50ebc5925cf0a15e8
LTC:
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 189512 W: 32620 L: 31904 D: 124988
http://tests.stockfishchess.org/tests/view/5d04bf740ebc5925cf0a17f0
Normally I would think such changes are risky, specially for PvNodes,
but after trying a few other versions, it seems this version is more
sound than I initially thought.
Aside from this, a small funtional change is made to return
singularBeta instead of beta to be more consistent with the fail-soft
logic used in other parts of search.
=============================
How to continue from there ?
We could try to audit other parts of the search where the "cutNode"
variable is used, and try to use dynamic info based on heuristic
eval rather than on this variable, to check if the idea behind this
patch could also be applied successfuly.
Bench: 3503788
2019-06-15 00:01:02 -06:00
|
|
|
// that multiple moves fail high, and we can prune the whole subtree by returning
|
|
|
|
// a soft bound.
|
2019-11-12 08:12:09 -07:00
|
|
|
else if (singularBeta >= beta)
|
Change multi-cut pruning condition
Use comparison of eval with beta to predict potential cutNodes. This
allows multi-cut pruning to also prune possibly mislabeled Pv and NonPv
nodes.
STC:
LLR: 2.95 (-2.94,2.94) [0.50,4.50]
Total: 54305 W: 12302 L: 11867 D: 30136
http://tests.stockfishchess.org/tests/view/5d048ba50ebc5925cf0a15e8
LTC:
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 189512 W: 32620 L: 31904 D: 124988
http://tests.stockfishchess.org/tests/view/5d04bf740ebc5925cf0a17f0
Normally I would think such changes are risky, specially for PvNodes,
but after trying a few other versions, it seems this version is more
sound than I initially thought.
Aside from this, a small funtional change is made to return
singularBeta instead of beta to be more consistent with the fail-soft
logic used in other parts of search.
=============================
How to continue from there ?
We could try to audit other parts of the search where the "cutNode"
variable is used, and try to use dynamic info based on heuristic
eval rather than on this variable, to check if the idea behind this
patch could also be applied successfuly.
Bench: 3503788
2019-06-15 00:01:02 -06:00
|
|
|
return singularBeta;
|
Apply multicut pruning more often
This patch increases number of nodes where we produce multicut cutoffs.
The idea is that if our ttMove failed to produce a singular extension
but ttValue is greater than beta we can afford to do one more reduced search
near beta excluding ttMove to see if it will produce a fail high -
and if it does so produce muticut by analogy to existing logic.
passed STC
https://tests.stockfishchess.org/tests/view/5e9a162b5b664cdba0ce6e28
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 58238 W: 11192 L: 10917 D: 36129
Ptnml(0-2): 1007, 6704, 13442, 6939, 1027
passed LTC
https://tests.stockfishchess.org/tests/view/5e9a1e845b664cdba0ce7411
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 137852 W: 17460 L: 16899 D: 103493
Ptnml(0-2): 916, 12610, 41383, 13031, 986
closes https://github.com/official-stockfish/Stockfish/pull/2640
bench 4881443
2020-04-17 18:28:47 -06:00
|
|
|
|
2020-06-24 14:19:58 -06:00
|
|
|
// If the eval of ttMove is greater than beta we try also if there is another
|
|
|
|
// move that pushes it over beta, if so also produce a cutoff.
|
Apply multicut pruning more often
This patch increases number of nodes where we produce multicut cutoffs.
The idea is that if our ttMove failed to produce a singular extension
but ttValue is greater than beta we can afford to do one more reduced search
near beta excluding ttMove to see if it will produce a fail high -
and if it does so produce muticut by analogy to existing logic.
passed STC
https://tests.stockfishchess.org/tests/view/5e9a162b5b664cdba0ce6e28
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 58238 W: 11192 L: 10917 D: 36129
Ptnml(0-2): 1007, 6704, 13442, 6939, 1027
passed LTC
https://tests.stockfishchess.org/tests/view/5e9a1e845b664cdba0ce7411
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 137852 W: 17460 L: 16899 D: 103493
Ptnml(0-2): 916, 12610, 41383, 13031, 986
closes https://github.com/official-stockfish/Stockfish/pull/2640
bench 4881443
2020-04-17 18:28:47 -06:00
|
|
|
else if (ttValue >= beta)
|
|
|
|
{
|
|
|
|
ss->excludedMove = move;
|
|
|
|
value = search<NonPV>(pos, ss, beta - 1, beta, (depth + 3) / 2, cutNode);
|
|
|
|
ss->excludedMove = MOVE_NONE;
|
|
|
|
|
|
|
|
if (value >= beta)
|
|
|
|
return beta;
|
|
|
|
}
|
2009-11-21 06:22:52 -07:00
|
|
|
}
|
Check Extension with Static Evaluation
extension for checking moves, at higher depth and more decisive positions.
stc:
LLR: 2.97 (-2.94,2.94) <-0.50,2.50>
Total: 87008 W: 7337 L: 7100 D: 72571
Ptnml(0-2): 264, 5737, 31270, 5964, 269
https://tests.stockfishchess.org/tests/view/60b1034787a1a67ae56c47b6
ltc:
LLR: 2.94 (-2.94,2.94) <0.50,3.50>
Total: 79320 W: 2629 L: 2432 D: 74259
Ptnml(0-2): 29, 2205, 35000, 2392, 34
https://tests.stockfishchess.org/tests/view/60b1ae0b87a1a67ae56c487c
closes https://github.com/official-stockfish/Stockfish/pull/3514
Bench: 4447112
2021-05-30 22:47:35 -06:00
|
|
|
else if ( givesCheck
|
|
|
|
&& depth > 6
|
|
|
|
&& abs(ss->staticEval) > Value(100))
|
|
|
|
extension = 1;
|
2019-01-29 07:26:03 -07:00
|
|
|
|
2019-11-12 10:36:12 -07:00
|
|
|
// Add extension to new depth
|
|
|
|
newDepth += extension;
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2014-10-03 22:07:55 -06:00
|
|
|
// Speculative prefetch as early as possible
|
2015-02-07 11:13:41 -07:00
|
|
|
prefetch(TT.first_entry(pos.key_after(move)));
|
2014-10-02 15:19:14 -06:00
|
|
|
|
2017-01-17 06:50:03 -07:00
|
|
|
// Update the current move (this must be done after singular extension search)
|
2011-05-23 07:14:47 -06:00
|
|
|
ss->currentMove = move;
|
continuation histories when in check
If in check, don't write to continuation histories ss-4, ss-6.
Adding inCheck to the stack was needed, and might be useful for
future patches.
Passed STC:
https://tests.stockfishchess.org/tests/view/5e9ee24acaaff5d60a50b812
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 61774 W: 11725 L: 11449 D: 38600
Ptnml(0-2): 971, 7211, 14322, 7337, 1046
Passed LTC:
https://tests.stockfishchess.org/tests/view/5e9eecb7caaff5d60a50b831
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 250822 W: 32067 L: 31179 D: 187576
Ptnml(0-2): 1745, 23126, 74824, 23928, 1788
closes https://github.com/official-stockfish/Stockfish/pull/2645
bench: 4808463
2020-04-21 12:55:41 -06:00
|
|
|
ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck]
|
2019-10-18 07:23:00 -06:00
|
|
|
[captureOrPromotion]
|
|
|
|
[movedPiece]
|
|
|
|
[to_sq(move)];
|
2011-05-23 07:14:47 -06:00
|
|
|
|
Introduce ProbCut for check evasions
The idea of this patch can be described as follows: if we are in check
and the transposition table move is a capture that returns a value
far above beta, we can assume that the opponent just blundered a piece
by giving check, and we return the transposition table value. This is
similar to the usual probCut logic for quiet moves, but with a different
threshold.
Passed STC
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 33440 W: 3056 L: 2891 D: 27493
Ptnml(0-2): 110, 2338, 11672, 2477, 123
https://tests.stockfishchess.org/tests/view/602cd1087f517a561bc49bda
Passed LTC
LLR: 2.98 (-2.94,2.94) {0.25,1.25}
Total: 10072 W: 401 L: 309 D: 9362
Ptnml(0-2): 2, 288, 4365, 378, 3
https://tests.stockfishchess.org/tests/view/602ceea57f517a561bc49bf0
The committed version has an additional fix to never return unproven wins
in the tablebase range or the mate range. This fix passed tests for non-
regression at STC and LTC:
STC:
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 26240 W: 2354 L: 2280 D: 21606
Ptnml(0-2): 85, 1763, 9372, 1793, 107
https://tests.stockfishchess.org/tests/view/602d86a87f517a561bc49c7a
LTC:
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 35304 W: 1299 L: 1256 D: 32749
Ptnml(0-2): 14, 1095, 15395, 1130, 18
https://tests.stockfishchess.org/tests/view/602d98d17f517a561bc49c83
Closes https://github.com/official-stockfish/Stockfish/pull/3362
Bench: 3830215
2021-02-20 14:48:08 -07:00
|
|
|
// Step 15. Make the move
|
Compute checkers from scratch
This micro-optimization only complicates the code and provides no benefit.
Removing it is even a speedup on my machine (i7-3770k, linux, gcc 4.9.1):
stat test master diff
mean 2,403,118 2,390,904 12,214
stdev 12,043 10,620 3,677
speedup 0.51%
P(speedup>0) 100.0%
No functional change.
2015-02-15 00:49:20 -07:00
|
|
|
pos.do_move(move, st, givesCheck);
|
2008-09-03 15:33:49 -06:00
|
|
|
|
Introduce DistanceFromPV
We introduce a metric for each internal node in search, called DistanceFromPV.
This distance indicated how far the current node is from the principal variation.
We then use this distance to search the nodes which are close to the PV a little
deeper (up to 4 plies deeper than the PV): this improves the quality of the search
at these nodes and bring better updates for the PV during search.
STC:
LLR: 2.96 (-2.94,2.94) {-0.25,1.25}
Total: 54936 W: 5047 L: 4850 D: 45039
Ptnml(0-2): 183, 3907, 19075, 4136, 167
https://tests.stockfishchess.org/tests/view/6037b88e7f517a561bc4a392
LTC:
LLR: 2.95 (-2.94,2.94) {0.25,1.25}
Total: 49608 W: 1880 L: 1703 D: 46025
Ptnml(0-2): 22, 1514, 21555, 1691, 22
https://tests.stockfishchess.org/tests/view/6038271b7f517a561bc4a3cb
Closes https://github.com/official-stockfish/Stockfish/pull/3369
Bench: 5037279
2021-02-26 02:13:37 -07:00
|
|
|
// Step 16. Late moves reduction / extension (LMR, ~200 Elo)
|
|
|
|
// We use various heuristics for the sons of a node after the first son has
|
|
|
|
// been searched. In general we would like to reduce them, but there are many
|
|
|
|
// cases where we extend a son if it has good chances to be "interesting".
|
2019-09-28 14:27:23 -06:00
|
|
|
if ( depth >= 3
|
Simplify reduced depth search
Simplification in reduced depth search.
STC https://tests.stockfishchess.org/tests/view/5f64c72fbb0cae038ca8f531
LLR: 2.94 (-2.94,2.94) {-1.25,0.25}
Total: 28320 W: 3475 L: 3359 D: 21486
Ptnml(0-2): 170, 2485, 8773, 2523, 209
LTC https://tests.stockfishchess.org/tests/view/5f650cfabb0cae038ca8f585
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 58392 W: 3354 L: 3285 D: 51753
Ptnml(0-2): 74, 2826, 23336, 2877, 83
closes https://github.com/official-stockfish/Stockfish/pull/3139
bench: 4201295
2020-09-20 01:03:37 -06:00
|
|
|
&& moveCount > 1 + 2 * rootNode
|
2019-05-05 07:58:52 -06:00
|
|
|
&& ( !captureOrPromotion
|
Less reduction for capture/promotions.
Exclude captures/promotions at expected cut nodes (which also not a
former PV node) from LMR if a response to the first previous
opponent move.
STC:
LLR: 2.93 (-2.94,2.94) <-0.50,2.50>
Total: 288656 W: 24886 L: 24413 D: 239357
Ptnml(0-2): 900, 19738, 102578, 20213, 899
https://tests.stockfishchess.org/tests/view/60ad505112066fd29979595b
LTC:
LLR: 2.97 (-2.94,2.94) <0.50,3.50>
Total: 31344 W: 1107 L: 975 D: 29262
Ptnml(0-2): 12, 879, 13757, 1013, 11
https://tests.stockfishchess.org/tests/view/60adffce12066fd2997959d2
closes https://github.com/official-stockfish/Stockfish/pull/3500
Bench: 3827710
2021-05-26 08:17:37 -06:00
|
|
|
|| (cutNode && (ss-1)->moveCount > 1)
|
Simplify usage of LMR for captures
This patch simplifies a lot of "enablers" for LMR when move is a capture or promotion.
After it we will have only 2 conditions - if node is a cutNode
or if it's an allNode that was not in PV,
so all captures or promotions wouldn't go thru LMR at any PVnodes.
passed STC
https://tests.stockfishchess.org/tests/view/60a40117ce8ea25a3ef03ca7
LLR: 2.95 (-2.94,2.94) <-2.50,0.50>
Total: 58976 W: 4875 L: 4807 D: 49294
Ptnml(0-2): 176, 3897, 21270, 3973, 172
passed LTC
https://tests.stockfishchess.org/tests/view/60a43ff8ce8ea25a3ef03d18
LLR: 2.93 (-2.94,2.94) <-2.50,0.50>
Total: 65272 W: 2203 L: 2165 D: 60904
Ptnml(0-2): 28, 1936, 28668, 1978, 26
closes https://github.com/official-stockfish/Stockfish/pull/3480
bench 4110764
2021-05-19 11:57:04 -06:00
|
|
|
|| (!PvNode && !formerPv))
|
Thread based reduction tweak.
For PV nodes at the first two plies no reductions are done for each fourth thread.
STC (8 threads):
LLR: 2.94 (-2.94,2.94) <-0.50,2.50>
Total: 53992 W: 3334 L: 3167 D: 47491
Ptnml(0-2): 64, 2713, 21285, 2860, 74
https://tests.stockfishchess.org/tests/view/6083b2d695e7f1852abd277a
LTC (8 threads):
LLR: 2.93 (-2.94,2.94) <0.50,3.50>
Total: 64888 W: 1888 L: 1725 D: 61275
Ptnml(0-2): 14, 1556, 29146, 1709, 19
https://tests.stockfishchess.org/tests/view/6084249595e7f1852abd2795
closes https://github.com/official-stockfish/Stockfish/pull/3443
No functional change (for one thread)
2021-04-24 23:09:35 -06:00
|
|
|
&& (!PvNode || ss->ply > 1 || thisThread->id() % 4 != 3))
|
2008-09-06 10:25:58 -06:00
|
|
|
{
|
2019-05-07 09:55:56 -06:00
|
|
|
Depth r = reduction(improving, depth, moveCount);
|
2016-08-16 07:53:45 -06:00
|
|
|
|
2021-05-13 20:47:41 -06:00
|
|
|
// Decrease reduction if the ttHit running average is large (~0 Elo)
|
Assorted search and eval parameter tune
Search and eval parameter tune.
STC https://tests.stockfishchess.org/tests/view/5fba850a67cbf42301d6b07d
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 24312 W: 2388 L: 2228 D: 19696
Ptnml(0-2): 85, 1800, 8241, 1930, 100
LTC https://tests.stockfishchess.org/tests/view/5fbad5ea67cbf42301d6b0fa
LLR: 2.95 (-2.94,2.94) {0.25,1.25}
Total: 88376 W: 3619 L: 3351 D: 81406
Ptnml(0-2): 56, 2977, 37849, 3255, 51
closes https://github.com/official-stockfish/Stockfish/pull/3232
bench: 3600361
2020-11-24 09:06:30 -07:00
|
|
|
if (thisThread->ttHitAverage > 537 * TtHitAverageResolution * TtHitAverageWindow / 1024)
|
Use exploration rate for reductions
This patch measures how frequently search is exploring new configurations.
This is done be computing a running average of ttHit. The ttHitAverage rate
is somewhat low (e.g. 30% for startpos) in the normal case, while it can be
very high if no progress is made (e.g. 90% for the fortress I used for testing).
This information can be used to influence search. In this patch, by adjusting
reductions if the rate > 50%. A first version (using a low ttHitAverageResolution
and this 50% threshold) passed testing:
STC
LLR: 2.96 (-2.94,2.94) [-1.50,4.50]
Total: 26425 W: 5837 L: 5650 D: 14938
http://tests.stockfishchess.org/tests/view/5dcede8b0ebc5902563258fa
LTC
LLR: 2.96 (-2.94,2.94) [0.00,3.50]
Total: 32313 W: 5392 L: 5128 D: 21793
http://tests.stockfishchess.org/tests/view/5dcefb1f0ebc590256325c0e
However, as discussed in pull request 2414, using a larger ttHitAverageResolution
gives a better approximation of the underlying distributions. This needs a slight
adjustment for the threshold as the new distributions are shifted a bit compared
to the older ones, and this threshold seemingly is sensitive (we used 0.53125 here).
https://github.com/official-stockfish/Stockfish/pull/2414
This final version also passed testing, and is used for the patch:
STC
LLR: 2.95 (-2.94,2.94) [-1.50,4.50]
Total: 16025 W: 3555 L: 3399 D: 9071
http://tests.stockfishchess.org/tests/view/5dd070b90ebc5902579e20c2
LTC
LLR: 2.96 (-2.94,2.94) [0.00,3.50]
Total: 37576 W: 6277 L: 5998 D: 25301
http://tests.stockfishchess.org/tests/view/5dd0f58e6f544e798086f224
Closes https://github.com/official-stockfish/Stockfish/pull/2414
Bench: 4989584
2019-11-15 10:16:27 -07:00
|
|
|
r--;
|
|
|
|
|
2021-01-31 05:46:05 -07:00
|
|
|
// Decrease reduction if position is or has been on the PV
|
2021-05-13 20:47:41 -06:00
|
|
|
// and node is not likely to fail low. (~3 Elo)
|
2021-03-19 12:43:25 -06:00
|
|
|
if ( ss->ttPv
|
|
|
|
&& !likelyFailLow)
|
2019-09-28 14:27:23 -06:00
|
|
|
r -= 2;
|
2019-01-09 07:05:28 -07:00
|
|
|
|
Increase reduction at root
when the best move does not change frequently
STC:
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 51320 W: 5159 L: 4956 D: 41205
Ptnml(0-2): 215, 3897, 17242, 4082, 224
https://tests.stockfishchess.org/tests/view/5faa072367cbf42301d6a767
LTC:
LLR: 2.98 (-2.94,2.94) {0.25,1.25}
Total: 15952 W: 762 L: 642 D: 14548
Ptnml(0-2): 8, 561, 6725, 667, 15
https://tests.stockfishchess.org/tests/view/5faa4c3567cbf42301d6a794
closes https://github.com/official-stockfish/Stockfish/pull/3225
Bench: 3954692
2020-11-10 10:28:43 -07:00
|
|
|
// Increase reduction at root and non-PV nodes when the best move does not change frequently
|
2021-03-19 12:43:25 -06:00
|
|
|
if ( (rootNode || !PvNode)
|
|
|
|
&& thisThread->rootDepth > 10
|
|
|
|
&& thisThread->bestMoveChanges <= 2)
|
Increase reduction based on the number of best move changes.
Thanks to Vizvezdenec for the PvNode idea and also to vondele the !PvNode idea.
Passed STC:
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 19120 W: 1998 L: 1839 D: 15283
Ptnml(0-2): 76, 1445, 6375, 1572, 92
https://tests.stockfishchess.org/tests/view/5fa8af3e67cbf42301d6a6c9
Passed LTC:
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 75584 W: 3454 L: 3205 D: 68925
Ptnml(0-2): 54, 2832, 31771, 3081, 54
closes https://github.com/official-stockfish/Stockfish/pull/3224
Bench: 3595418
2020-11-08 19:43:32 -07:00
|
|
|
r++;
|
|
|
|
|
Simplify LMR rule for non-checking captures
We simplify away the complicated rule in LMR for "non-checking captures
likely to be bad", as it seems not to bring any strength anymore.
STC:
LLR: 2.94 (-2.94,2.94) <-2.50,0.50>
Total: 55256 W: 4972 L: 4897 D: 45387
Ptnml(0-2): 177, 3976, 19234, 4077, 164
https://tests.stockfishchess.org/tests/view/609adf3b3a33eb67a844f842
LTC:
LLR: 2.95 (-2.94,2.94) <-2.50,0.50>
Total: 10344 W: 437 L: 353 D: 9554
Ptnml(0-2): 1, 322, 4449, 392, 8
https://tests.stockfishchess.org/tests/view/609b3dfa3a33eb67a844f88e
--
While at it, we also update the Elo estimate of the previous rule in LMR
(see https://tests.stockfishchess.org/tests/view/609af2a63a33eb67a844f867).
closes https://github.com/official-stockfish/Stockfish/pull/3460
Bench: 3840688
2021-05-12 06:38:26 -06:00
|
|
|
// Decrease reduction if opponent's move count is high (~1 Elo)
|
Retuned values after eval quantize patch.
The last search tune patch was tested before the implementation of #2733 which
presumably changed the search characteristics noticeably. Another tuning run was
done, see https://tests.stockfishchess.org/tests/view/5ee5b434ca6c451633a9a08c
and the updated values passed these tests:
STC:
LLR: 2.93 (-2.94,2.94) {-0.50,1.50}
Total: 34352 W: 6600 L: 6360 D: 21392
Ptnml(0-2): 581, 3947, 7914, 4119, 615
https://tests.stockfishchess.org/tests/view/5ee62f05ca6c451633a9a15f
LTC 60+0.6 th 1 :
LLR: 2.97 (-2.94,2.94) {0.25,1.75}
Total: 11176 W: 1499 L: 1304 D: 8373
Ptnml(0-2): 69, 933, 3403, 1100, 83
https://tests.stockfishchess.org/tests/view/5ee6205bca6c451633a9a147
SMP LTC 20+0.2 th 8 :
LLR: 2.93 (-2.94,2.94) {0.25,1.75}
Total: 54032 W: 6126 L: 5826 D: 42080
Ptnml(0-2): 278, 4454, 17280, 4698, 306
https://tests.stockfishchess.org/tests/view/5ee62f25ca6c451633a9a162
Closes https://github.com/official-stockfish/Stockfish/pull/2742
Bench 4957812
2020-06-14 14:50:27 -06:00
|
|
|
if ((ss-1)->moveCount > 13)
|
2019-09-28 14:27:23 -06:00
|
|
|
r--;
|
2019-05-02 11:36:25 -06:00
|
|
|
|
2021-05-11 08:04:02 -06:00
|
|
|
// Decrease reduction if ttMove has been singularly extended (~1 Elo)
|
Singular quiet LMR
If ttMove is a capture and had a singular extension, it is probably the best move.
No need to make a decrease of LMR on other moves.
STC
LLR: 2.96 (-2.94,2.94) {-0.50,1.50}
Total: 41968 W: 8170 L: 7918 D: 25880
Ptnml(0-2): 733, 4770, 9726, 5022, 733
https://tests.stockfishchess.org/tests/view/5ed6b666f29b40b0fc95a884
LTC
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 71376 W: 9200 L: 8827 D: 53349
Ptnml(0-2): 486, 6544, 21342, 6743, 573
https://tests.stockfishchess.org/tests/view/5ed7578bf29b40b0fc95a8c9
closes https://github.com/official-stockfish/Stockfish/pull/2713
Bench: 4733799
2020-06-02 14:27:11 -06:00
|
|
|
if (singularQuietLMR)
|
Simplify singularQuietLMR
remove formerPV dependence
STC https://tests.stockfishchess.org/tests/view/5f4cb922ba100690c5cc5d35
LLR: 2.96 (-2.94,2.94) {-1.25,0.25}
Total: 113672 W: 12347 L: 12368 D: 88957
Ptnml(0-2): 566, 9537, 36699, 9420, 614
LTC https://tests.stockfishchess.org/tests/view/5f4e8474ba100690c5cc5e12
LLR: 2.93 (-2.94,2.94) {-0.75,0.25}
Total: 43032 W: 2298 L: 2227 D: 38507
Ptnml(0-2): 45, 1940, 17475, 2011, 45
closes https://github.com/official-stockfish/Stockfish/pull/3102
bench: 3290084
2020-09-03 04:18:42 -06:00
|
|
|
r--;
|
2017-09-04 14:27:22 -06:00
|
|
|
|
Increased reduction for captures in LMR
It now does, in LMR, an increased on reduction by 1 for captures in cut nodes.
STC:
LLR: 2.93 (-2.94,2.94) <-0.50,2.50>
Total: 30656 W: 2565 L: 2397 D: 25694
Ptnml(0-2): 63, 2012, 11029, 2142, 82
https://tests.stockfishchess.org/tests/view/60a96733ce8ea25a3ef04178
LTC:
LLR: 2.93 (-2.94,2.94) <0.50,3.50>
Total: 124840 W: 4139 L: 3878 D: 116823
Ptnml(0-2): 48, 3480, 55100, 3747, 45
https://tests.stockfishchess.org/tests/view/60a995f5ce8ea25a3ef041b7
closes https://github.com/official-stockfish/Stockfish/pull/3494
bench: 3864295
2021-05-24 05:15:04 -06:00
|
|
|
// Increase reduction for cut nodes (~3 Elo)
|
|
|
|
if (cutNode)
|
|
|
|
r += 1 + !captureOrPromotion;
|
|
|
|
|
Simplify LMR rule for non-checking captures
We simplify away the complicated rule in LMR for "non-checking captures
likely to be bad", as it seems not to bring any strength anymore.
STC:
LLR: 2.94 (-2.94,2.94) <-2.50,0.50>
Total: 55256 W: 4972 L: 4897 D: 45387
Ptnml(0-2): 177, 3976, 19234, 4077, 164
https://tests.stockfishchess.org/tests/view/609adf3b3a33eb67a844f842
LTC:
LLR: 2.95 (-2.94,2.94) <-2.50,0.50>
Total: 10344 W: 437 L: 353 D: 9554
Ptnml(0-2): 1, 322, 4449, 392, 8
https://tests.stockfishchess.org/tests/view/609b3dfa3a33eb67a844f88e
--
While at it, we also update the Elo estimate of the previous rule in LMR
(see https://tests.stockfishchess.org/tests/view/609af2a63a33eb67a844f867).
closes https://github.com/official-stockfish/Stockfish/pull/3460
Bench: 3840688
2021-05-12 06:38:26 -06:00
|
|
|
if (!captureOrPromotion)
|
2018-08-08 01:45:58 -06:00
|
|
|
{
|
2021-05-11 08:04:02 -06:00
|
|
|
// Increase reduction if ttMove is a capture (~3 Elo)
|
2017-06-21 15:05:14 -06:00
|
|
|
if (ttCapture)
|
2019-09-28 14:27:23 -06:00
|
|
|
r++;
|
2017-06-23 23:15:46 -06:00
|
|
|
|
2018-05-22 12:30:58 -06:00
|
|
|
ss->statScore = thisThread->mainHistory[us][from_to(move)]
|
2017-08-09 19:43:30 -06:00
|
|
|
+ (*contHist[0])[movedPiece][to_sq(move)]
|
|
|
|
+ (*contHist[1])[movedPiece][to_sq(move)]
|
|
|
|
+ (*contHist[3])[movedPiece][to_sq(move)]
|
Tuning Search
This patch tunes constant in search.cpp
STC:
LLR: 2.94 (-2.94,2.94) <-0.50,2.50>
Total: 30648 W: 2580 L: 2410 D: 25658
Ptnml(0-2): 80, 1969, 11093, 2065, 117
https://tests.stockfishchess.org/tests/view/60a71d3cce8ea25a3ef03fae
LTC:
LLR: 2.95 (-2.94,2.94) <0.50,3.50>
Total: 52896 W: 1776 L: 1617 D: 49503
Ptnml(0-2): 13, 1462, 23347, 1605, 21
https://tests.stockfishchess.org/tests/view/60a794ddce8ea25a3ef0400a
closes https://github.com/official-stockfish/Stockfish/pull/3491
Bench: 4004731
2021-05-21 23:47:23 -06:00
|
|
|
- 4923;
|
2016-10-24 08:05:02 -06:00
|
|
|
|
2018-04-18 11:17:16 -06:00
|
|
|
// Decrease/increase reduction for moves with a good/bad history (~30 Elo)
|
2021-05-13 20:47:41 -06:00
|
|
|
if (!ss->inCheck)
|
Tuning Search
This patch tunes constant in search.cpp
STC:
LLR: 2.94 (-2.94,2.94) <-0.50,2.50>
Total: 30648 W: 2580 L: 2410 D: 25658
Ptnml(0-2): 80, 1969, 11093, 2065, 117
https://tests.stockfishchess.org/tests/view/60a71d3cce8ea25a3ef03fae
LTC:
LLR: 2.95 (-2.94,2.94) <0.50,3.50>
Total: 52896 W: 1776 L: 1617 D: 49503
Ptnml(0-2): 13, 1462, 23347, 1605, 21
https://tests.stockfishchess.org/tests/view/60a794ddce8ea25a3ef0400a
closes https://github.com/official-stockfish/Stockfish/pull/3491
Bench: 4004731
2021-05-21 23:47:23 -06:00
|
|
|
r -= ss->statScore / 14721;
|
2016-08-16 07:53:45 -06:00
|
|
|
}
|
Tweak reductions for captures/promotions
From the third move reduce captures and promotions more if remaining depth is low.
STC:
LLR: 2.94 (-2.94,2.94) {-1.00,3.00}
Total: 25218 W: 5008 L: 4837 D: 15373
Ptnml(0-2): 439, 2950, 5717, 3001, 499
http://tests.stockfishchess.org/tests/view/5e1b33abd12216a2857e6359
LTC:
LLR: 2.95 (-2.94,2.94) {0.00,2.00}
Total: 35491 W: 4760 L: 4524 D: 26207
Ptnml(0-2): 264, 3288, 10413, 3460, 294
http://tests.stockfishchess.org/tests/view/5e1b88d5d12216a2857e6385
Closes https://github.com/official-stockfish/Stockfish/pull/2488
Bench: 4979757
2020-01-13 03:19:03 -07:00
|
|
|
|
Replace distanceFromPv with a better logic
This patch removes the recently introduced distanceFromPv logic, and replaces
it with following logic: if reduction of moves with low movecount is really
negative, we search them deeper than the first move.
passed STC:
LLR: 2.95 (-2.94,2.94) {-0.20,1.10}
Total: 153008 W: 13913 L: 13579 D: 125516
Ptnml(0-2): 547, 10811, 53470, 11113, 563
https://tests.stockfishchess.org/tests/view/6069c9d02b2df919fd5f04d2
passed LTC:
LLR: 2.94 (-2.94,2.94) {0.20,0.90}
Total: 101920 W: 3964 L: 3699 D: 94257
Ptnml(0-2): 55, 3279, 44019, 3560, 47
https://tests.stockfishchess.org/tests/view/606a99fd2b2df919fd5f0532
Closes https://github.com/official-stockfish/Stockfish/pull/3421
Bench: 4191632
2021-04-06 07:51:05 -06:00
|
|
|
// In general we want to cap the LMR depth search at newDepth. But if
|
|
|
|
// reductions are really negative and movecount is low, we allow this move
|
|
|
|
// to be searched deeper than the first move.
|
|
|
|
Depth d = std::clamp(newDepth - r, 1, newDepth + (r < -1 && moveCount <= 5));
|
2011-06-25 07:31:57 -06:00
|
|
|
|
2018-05-08 02:43:46 -06:00
|
|
|
value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, true);
|
2011-06-25 07:31:57 -06:00
|
|
|
|
Introduce DistanceFromPV
We introduce a metric for each internal node in search, called DistanceFromPV.
This distance indicated how far the current node is from the principal variation.
We then use this distance to search the nodes which are close to the PV a little
deeper (up to 4 plies deeper than the PV): this improves the quality of the search
at these nodes and bring better updates for the PV during search.
STC:
LLR: 2.96 (-2.94,2.94) {-0.25,1.25}
Total: 54936 W: 5047 L: 4850 D: 45039
Ptnml(0-2): 183, 3907, 19075, 4136, 167
https://tests.stockfishchess.org/tests/view/6037b88e7f517a561bc4a392
LTC:
LLR: 2.95 (-2.94,2.94) {0.25,1.25}
Total: 49608 W: 1880 L: 1703 D: 46025
Ptnml(0-2): 22, 1514, 21555, 1691, 22
https://tests.stockfishchess.org/tests/view/6038271b7f517a561bc4a3cb
Closes https://github.com/official-stockfish/Stockfish/pull/3369
Bench: 5037279
2021-02-26 02:13:37 -07:00
|
|
|
// If the son is reduced and fails high it will be re-searched at full depth
|
|
|
|
doFullDepthSearch = value > alpha && d < newDepth;
|
2020-03-14 10:04:50 -06:00
|
|
|
didLMR = true;
|
2011-11-19 05:55:26 -07:00
|
|
|
}
|
|
|
|
else
|
2020-03-14 10:04:50 -06:00
|
|
|
{
|
|
|
|
doFullDepthSearch = !PvNode || moveCount > 1;
|
|
|
|
didLMR = false;
|
|
|
|
}
|
2010-05-08 02:54:51 -06:00
|
|
|
|
Introduce ProbCut for check evasions
The idea of this patch can be described as follows: if we are in check
and the transposition table move is a capture that returns a value
far above beta, we can assume that the opponent just blundered a piece
by giving check, and we return the transposition table value. This is
similar to the usual probCut logic for quiet moves, but with a different
threshold.
Passed STC
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 33440 W: 3056 L: 2891 D: 27493
Ptnml(0-2): 110, 2338, 11672, 2477, 123
https://tests.stockfishchess.org/tests/view/602cd1087f517a561bc49bda
Passed LTC
LLR: 2.98 (-2.94,2.94) {0.25,1.25}
Total: 10072 W: 401 L: 309 D: 9362
Ptnml(0-2): 2, 288, 4365, 378, 3
https://tests.stockfishchess.org/tests/view/602ceea57f517a561bc49bf0
The committed version has an additional fix to never return unproven wins
in the tablebase range or the mate range. This fix passed tests for non-
regression at STC and LTC:
STC:
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 26240 W: 2354 L: 2280 D: 21606
Ptnml(0-2): 85, 1763, 9372, 1793, 107
https://tests.stockfishchess.org/tests/view/602d86a87f517a561bc49c7a
LTC:
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 35304 W: 1299 L: 1256 D: 32749
Ptnml(0-2): 14, 1095, 15395, 1130, 18
https://tests.stockfishchess.org/tests/view/602d98d17f517a561bc49c83
Closes https://github.com/official-stockfish/Stockfish/pull/3362
Bench: 3830215
2021-02-20 14:48:08 -07:00
|
|
|
// Step 17. Full depth search when LMR is skipped or fails high
|
2011-11-19 05:55:26 -07:00
|
|
|
if (doFullDepthSearch)
|
2019-07-11 23:22:46 -06:00
|
|
|
{
|
2018-05-08 02:43:46 -06:00
|
|
|
value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode);
|
2010-02-24 03:55:58 -07:00
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// If the move passed LMR update its stats
|
2019-10-18 18:20:38 -06:00
|
|
|
if (didLMR && !captureOrPromotion)
|
2019-07-11 23:22:46 -06:00
|
|
|
{
|
2019-07-12 02:17:24 -06:00
|
|
|
int bonus = value > alpha ? stat_bonus(newDepth)
|
|
|
|
: -stat_bonus(newDepth);
|
2019-07-11 23:22:46 -06:00
|
|
|
|
|
|
|
update_continuation_histories(ss, movedPiece, to_sq(move), bonus);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2013-12-02 11:04:09 -07:00
|
|
|
// For PV nodes only, do a full PV search on the first move or after a fail
|
|
|
|
// high (in the latter case search only if value < beta), otherwise let the
|
2016-01-16 14:34:29 -07:00
|
|
|
// parent node fail low with value <= alpha and try another move.
|
2016-01-18 15:20:16 -07:00
|
|
|
if (PvNode && (moveCount == 1 || (value > alpha && (rootNode || value < beta))))
|
2014-11-18 03:57:57 -07:00
|
|
|
{
|
|
|
|
(ss+1)->pv = pv;
|
2014-11-21 01:10:52 -07:00
|
|
|
(ss+1)->pv[0] = MOVE_NONE;
|
|
|
|
|
Reduce big time spikes by reducing PV re-searches.
Save time by reducing PV re-searches above original depth. Instead use 5% extra time on every move.
STC 10+0.1 th 1 :
LLR: 2.93 (-2.94,2.94) {-0.25,1.25}
Total: 90688 W: 9702 L: 9436 D: 71550
Ptnml(0-2): 408, 7252, 29792, 7450, 442
https://tests.stockfishchess.org/tests/view/5f8df807bacb75a4f9a47223
LTC 60+0.6 th 1 :
LLR: 2.97 (-2.94,2.94) {0.25,1.25}
Total: 97856 W: 4602 L: 4303 D: 88951
Ptnml(0-2): 53, 3757, 41057, 3960, 101
https://tests.stockfishchess.org/tests/view/5f8ec4872c92c7fe3a8c602d
closes https://github.com/official-stockfish/Stockfish/pull/3192
Bench 3943959
2020-10-21 07:52:13 -06:00
|
|
|
value = -search<PV>(pos, ss+1, -beta, -alpha,
|
|
|
|
std::min(maxNextDepth, newDepth), false);
|
2014-11-12 14:13:55 -07:00
|
|
|
}
|
2014-11-18 03:57:57 -07:00
|
|
|
|
Introduce ProbCut for check evasions
The idea of this patch can be described as follows: if we are in check
and the transposition table move is a capture that returns a value
far above beta, we can assume that the opponent just blundered a piece
by giving check, and we return the transposition table value. This is
similar to the usual probCut logic for quiet moves, but with a different
threshold.
Passed STC
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 33440 W: 3056 L: 2891 D: 27493
Ptnml(0-2): 110, 2338, 11672, 2477, 123
https://tests.stockfishchess.org/tests/view/602cd1087f517a561bc49bda
Passed LTC
LLR: 2.98 (-2.94,2.94) {0.25,1.25}
Total: 10072 W: 401 L: 309 D: 9362
Ptnml(0-2): 2, 288, 4365, 378, 3
https://tests.stockfishchess.org/tests/view/602ceea57f517a561bc49bf0
The committed version has an additional fix to never return unproven wins
in the tablebase range or the mate range. This fix passed tests for non-
regression at STC and LTC:
STC:
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 26240 W: 2354 L: 2280 D: 21606
Ptnml(0-2): 85, 1763, 9372, 1793, 107
https://tests.stockfishchess.org/tests/view/602d86a87f517a561bc49c7a
LTC:
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 35304 W: 1299 L: 1256 D: 32749
Ptnml(0-2): 14, 1095, 15395, 1130, 18
https://tests.stockfishchess.org/tests/view/602d98d17f517a561bc49c83
Closes https://github.com/official-stockfish/Stockfish/pull/3362
Bench: 3830215
2021-02-20 14:48:08 -07:00
|
|
|
// Step 18. Undo move
|
2009-02-22 09:49:52 -07:00
|
|
|
pos.undo_move(move);
|
2008-08-31 23:59:13 -06:00
|
|
|
|
|
|
|
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
|
2008-09-03 15:33:49 -06:00
|
|
|
|
Introduce ProbCut for check evasions
The idea of this patch can be described as follows: if we are in check
and the transposition table move is a capture that returns a value
far above beta, we can assume that the opponent just blundered a piece
by giving check, and we return the transposition table value. This is
similar to the usual probCut logic for quiet moves, but with a different
threshold.
Passed STC
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 33440 W: 3056 L: 2891 D: 27493
Ptnml(0-2): 110, 2338, 11672, 2477, 123
https://tests.stockfishchess.org/tests/view/602cd1087f517a561bc49bda
Passed LTC
LLR: 2.98 (-2.94,2.94) {0.25,1.25}
Total: 10072 W: 401 L: 309 D: 9362
Ptnml(0-2): 2, 288, 4365, 378, 3
https://tests.stockfishchess.org/tests/view/602ceea57f517a561bc49bf0
The committed version has an additional fix to never return unproven wins
in the tablebase range or the mate range. This fix passed tests for non-
regression at STC and LTC:
STC:
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 26240 W: 2354 L: 2280 D: 21606
Ptnml(0-2): 85, 1763, 9372, 1793, 107
https://tests.stockfishchess.org/tests/view/602d86a87f517a561bc49c7a
LTC:
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 35304 W: 1299 L: 1256 D: 32749
Ptnml(0-2): 14, 1095, 15395, 1130, 18
https://tests.stockfishchess.org/tests/view/602d98d17f517a561bc49c83
Closes https://github.com/official-stockfish/Stockfish/pull/3362
Bench: 3830215
2021-02-20 14:48:08 -07:00
|
|
|
// Step 19. Check for a new best move
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
// Finished searching the move. If a stop occurred, the return value of
|
|
|
|
// the search cannot be trusted, and we return immediately without
|
2014-05-01 00:28:49 -06:00
|
|
|
// updating best move, PV and TT.
|
2017-07-13 17:07:19 -06:00
|
|
|
if (Threads.stop.load(std::memory_order_relaxed))
|
2014-05-01 08:25:17 -06:00
|
|
|
return VALUE_ZERO;
|
2013-08-15 01:36:26 -06:00
|
|
|
|
2016-01-18 15:20:16 -07:00
|
|
|
if (rootNode)
|
2011-01-16 04:02:32 -07:00
|
|
|
{
|
2015-10-23 23:27:24 -06:00
|
|
|
RootMove& rm = *std::find(thisThread->rootMoves.begin(),
|
|
|
|
thisThread->rootMoves.end(), move);
|
2011-01-16 04:02:32 -07:00
|
|
|
|
2018-02-12 14:57:42 -07:00
|
|
|
// PV move or new best move?
|
2014-11-08 03:39:38 -07:00
|
|
|
if (moveCount == 1 || value > alpha)
|
2011-01-16 04:02:32 -07:00
|
|
|
{
|
2011-12-12 09:55:20 -07:00
|
|
|
rm.score = value;
|
2017-07-13 17:30:03 -06:00
|
|
|
rm.selDepth = thisThread->selDepth;
|
2014-11-12 14:13:55 -07:00
|
|
|
rm.pv.resize(1);
|
2014-11-21 01:10:52 -07:00
|
|
|
|
|
|
|
assert((ss+1)->pv);
|
|
|
|
|
|
|
|
for (Move* m = (ss+1)->pv; *m != MOVE_NONE; ++m)
|
|
|
|
rm.pv.push_back(*m);
|
2011-01-16 04:02:32 -07:00
|
|
|
|
|
|
|
// We record how often the best move has been changed in each
|
2020-12-01 05:02:35 -07:00
|
|
|
// iteration. This information is used for time management and LMR
|
Use average bestMoveChanges across all threads #2072
The current update only by main thread depends on the luck of
whether main thread sees any/many changes to the best move or not.
It then makes large, lumpy changes to the time to be
used (1x, 2x, 3x, etc) depending on that sample of 1.
Use the average across all threads to get a more reliable
number with a smoother distribution.
STC @ 5+0.05 th 4 :
LLR: 2.95 (-2.94,2.94) [0.50,4.50]
Total: 51899 W: 11446 L: 11029 D: 29424
http://tests.stockfishchess.org/tests/view/5ca32ff20ebc5925cf0016fb
STC @ 5+0.05 th 8 :
LLR: 2.96 (-2.94,2.94) [0.50,4.50]
Total: 13851 W: 2843 L: 2620 D: 8388
http://tests.stockfishchess.org/tests/view/5ca35ae00ebc5925cf001adb
LTC @ 20+0.2 th 8 :
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 48527 W: 7941 L: 7635 D: 32951
http://tests.stockfishchess.org/tests/view/5ca37cb70ebc5925cf001cec
Further work:
Similar changes might be possible for the fallingEval and timeReduction calculations (and elsewhere?), using either the min, average or max values across all threads.
Bench 3506898
2019-04-03 01:35:55 -06:00
|
|
|
if (moveCount > 1)
|
|
|
|
++thisThread->bestMoveChanges;
|
2011-02-17 01:24:55 -07:00
|
|
|
}
|
|
|
|
else
|
2017-07-23 18:25:23 -06:00
|
|
|
// All other moves but the PV are set to the lowest value: this
|
|
|
|
// is not a problem when sorting because the sort is stable and the
|
2013-12-02 11:04:09 -07:00
|
|
|
// move position in the list is preserved - just the PV is pushed up.
|
2011-12-12 09:55:20 -07:00
|
|
|
rm.score = -VALUE_INFINITE;
|
2011-12-10 11:14:13 -07:00
|
|
|
}
|
2011-01-16 04:02:32 -07:00
|
|
|
|
2011-08-06 02:15:46 -06:00
|
|
|
if (value > bestValue)
|
|
|
|
{
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
bestValue = value;
|
2011-08-06 02:15:46 -06:00
|
|
|
|
2012-10-03 06:11:20 -06:00
|
|
|
if (value > alpha)
|
2012-10-01 01:33:13 -06:00
|
|
|
{
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
bestMove = move;
|
2012-10-03 06:11:20 -06:00
|
|
|
|
2016-01-18 15:20:16 -07:00
|
|
|
if (PvNode && !rootNode) // Update pv even in fail-high case
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
update_pv(ss->pv, move, (ss+1)->pv);
|
2014-11-12 14:13:55 -07:00
|
|
|
|
2013-01-13 04:34:31 -07:00
|
|
|
if (PvNode && value < beta) // Update alpha! Always alpha < beta
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
alpha = value;
|
2012-11-17 04:44:19 -07:00
|
|
|
else
|
2012-10-05 07:00:35 -06:00
|
|
|
{
|
2012-11-17 04:44:19 -07:00
|
|
|
assert(value >= beta); // Fail high
|
2012-10-05 07:00:35 -06:00
|
|
|
break;
|
|
|
|
}
|
2011-08-06 02:15:46 -06:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// If the move is worse than some previously searched move, remember it to update its stats later
|
2018-02-12 14:57:42 -07:00
|
|
|
if (move != bestMove)
|
|
|
|
{
|
|
|
|
if (captureOrPromotion && captureCount < 32)
|
|
|
|
capturesSearched[captureCount++] = move;
|
|
|
|
|
|
|
|
else if (!captureOrPromotion && quietCount < 64)
|
|
|
|
quietsSearched[quietCount++] = move;
|
|
|
|
}
|
2008-08-31 23:59:13 -06:00
|
|
|
}
|
|
|
|
|
2016-01-16 14:34:29 -07:00
|
|
|
// The following condition would detect a stop only after move loop has been
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
// completed. But in this case bestValue is valid because we have fully
|
|
|
|
// searched our subtree, and we can anyhow save the result in TT.
|
2014-05-01 00:28:49 -06:00
|
|
|
/*
|
2017-07-13 17:07:19 -06:00
|
|
|
if (Threads.stop)
|
2014-05-01 00:28:49 -06:00
|
|
|
return VALUE_DRAW;
|
|
|
|
*/
|
|
|
|
|
Introduce ProbCut for check evasions
The idea of this patch can be described as follows: if we are in check
and the transposition table move is a capture that returns a value
far above beta, we can assume that the opponent just blundered a piece
by giving check, and we return the transposition table value. This is
similar to the usual probCut logic for quiet moves, but with a different
threshold.
Passed STC
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 33440 W: 3056 L: 2891 D: 27493
Ptnml(0-2): 110, 2338, 11672, 2477, 123
https://tests.stockfishchess.org/tests/view/602cd1087f517a561bc49bda
Passed LTC
LLR: 2.98 (-2.94,2.94) {0.25,1.25}
Total: 10072 W: 401 L: 309 D: 9362
Ptnml(0-2): 2, 288, 4365, 378, 3
https://tests.stockfishchess.org/tests/view/602ceea57f517a561bc49bf0
The committed version has an additional fix to never return unproven wins
in the tablebase range or the mate range. This fix passed tests for non-
regression at STC and LTC:
STC:
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 26240 W: 2354 L: 2280 D: 21606
Ptnml(0-2): 85, 1763, 9372, 1793, 107
https://tests.stockfishchess.org/tests/view/602d86a87f517a561bc49c7a
LTC:
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 35304 W: 1299 L: 1256 D: 32749
Ptnml(0-2): 14, 1095, 15395, 1130, 18
https://tests.stockfishchess.org/tests/view/602d98d17f517a561bc49c83
Closes https://github.com/official-stockfish/Stockfish/pull/3362
Bench: 3830215
2021-02-20 14:48:08 -07:00
|
|
|
// Step 20. Check for mate and stalemate
|
2011-10-18 04:24:47 -06:00
|
|
|
// All legal moves have been searched and if there are no legal moves, it
|
2016-01-16 14:34:29 -07:00
|
|
|
// must be a mate or a stalemate. If we are in a singular extension search then
|
2014-05-01 00:28:49 -06:00
|
|
|
// return a fail low score.
|
2016-10-03 07:36:40 -06:00
|
|
|
|
continuation histories when in check
If in check, don't write to continuation histories ss-4, ss-6.
Adding inCheck to the stack was needed, and might be useful for
future patches.
Passed STC:
https://tests.stockfishchess.org/tests/view/5e9ee24acaaff5d60a50b812
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 61774 W: 11725 L: 11449 D: 38600
Ptnml(0-2): 971, 7211, 14322, 7337, 1046
Passed LTC:
https://tests.stockfishchess.org/tests/view/5e9eecb7caaff5d60a50b831
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 250822 W: 32067 L: 31179 D: 187576
Ptnml(0-2): 1745, 23126, 74824, 23928, 1788
closes https://github.com/official-stockfish/Stockfish/pull/2645
bench: 4808463
2020-04-21 12:55:41 -06:00
|
|
|
assert(moveCount || !ss->inCheck || excludedMove || !MoveList<LEGAL>(pos).size());
|
2016-10-03 07:36:40 -06:00
|
|
|
|
2012-10-03 06:11:20 -06:00
|
|
|
if (!moveCount)
|
2021-03-19 12:43:25 -06:00
|
|
|
bestValue = excludedMove ? alpha :
|
|
|
|
ss->inCheck ? mated_in(ss->ply)
|
|
|
|
: VALUE_DRAW;
|
2016-08-24 08:52:05 -06:00
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// If there is a move which produces search value greater than alpha we update stats of searched moves
|
Refactor final stats updates.
This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done.
Effectively, all stat updates that need to be done after search is finished and a bestmove is found,
are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```.
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```.
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture).
passed non-regression STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 75196 W: 16364 L: 16347 D: 42485
http://tests.stockfishchess.org/tests/view/5db004ec0ebc5902c06db9e1
The diff is most easily readable as ```git diff master --patience```
No functional change
2019-10-23 00:26:47 -06:00
|
|
|
else if (bestMove)
|
|
|
|
update_all_stats(pos, ss, bestMove, bestValue, beta, prevSq,
|
Revert 5 recent patches
Revert 5 patches which were merged, but lead to a regression test that showed negative Elo gain:
http://tests.stockfishchess.org/tests/view/5e307251ab2d69d58394fdb9
This was discussed in depth in:
https://github.com/official-stockfish/Stockfish/issues/2531
Each patch was removed and tested as a simplification, full list below, and the whole combo as well.
After the revert the regression test showed a neutral result:
http://tests.stockfishchess.org/tests/view/5e334851708b13464ceea33c
As a result of this experience, the SPRT testing bounds will be made more strict.
Reverted patches:
1 Dynamic Complexity 6d0eabd5fe2961551477820ab7619e2c31e01ffd :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31fcacec661e2e6a340d08 :
LLR: 2.97 (-2.94,2.94) {-1.50,0.50}
Total: 38130 W: 7326 L: 7189 D: 23615
Ptnml(0-2): 677, 4346, 8843, 4545, 646
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c18fec661e2e6a340d73 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 38675 W: 4941 L: 4866 D: 28868
Ptnml(0-2): 270, 3556, 11429, 3584, 291
3 More bonus for bestMoves on past PV nodes 71e0b5385e2717679a57c6b77d8c7ac5fff3b89f :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31fe93ec661e2e6a340d10 :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 46100 W: 8853 L: 8727 D: 28520
Ptnml(0-2): 796, 5297, 10749, 5387, 813
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c187ec661e2e6a340d71 :
LLR: 2.96 (-2.94,2.94) {-1.50,0.50}
Total: 16920 W: 2161 L: 2055 D: 12704
Ptnml(0-2): 115, 1498, 5006, 1569, 130
4 Tweak Restricted Piece Bonus 0ae00454ba6928d181b46103e5c83e6d58fcebe5 :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31fefaec661e2e6a340d15 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 88328 W: 17060 L: 16997 D: 54271
Ptnml(0-2): 1536, 10446, 20169, 10422, 1581
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c17aec661e2e6a340d6f :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 34784 W: 4551 L: 4466 D: 25767
Ptnml(0-2): 255, 3279, 10061, 3345, 262
5 History update for pruned captures 01b6088af39902001d2d6844561b6a2faa549282 :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31ff5eec661e2e6a340d1a :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 29541 W: 5735 L: 5588 D: 18218
Ptnml(0-2): 483, 3445, 6820, 3469, 545
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c196ec661e2e6a340d75 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 22177 W: 2854 L: 2757 D: 16566
Ptnml(0-2): 143, 2005, 6555, 2055, 164
6 Tweak trapped rook penalty 18fc21eba0368fd5e3c4c4b8ee1000c9ac445425 :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31ffb1ec661e2e6a340d1c :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 24476 W: 4727 L: 4569 D: 15180
Ptnml(0-2): 390, 2834, 5659, 2933, 417
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c19eec661e2e6a340d77 :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 97332 W: 12492 L: 12466 D: 72374
Ptnml(0-2): 690, 9107, 28738, 9034, 720
All 5 as one simplification :
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e334098708b13464ceea330 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 7829 W: 1079 L: 964 D: 5786
Ptnml(0-2): 52, 690, 2281, 781, 65
Bench: 5153165
2020-01-30 13:44:04 -07:00
|
|
|
quietsSearched, quietCount, capturesSearched, captureCount, depth);
|
2018-12-06 06:39:41 -07:00
|
|
|
|
2015-10-12 15:00:54 -06:00
|
|
|
// Bonus for prior countermove that caused the fail low
|
2019-09-28 14:27:23 -06:00
|
|
|
else if ( (depth >= 3 || PvNode)
|
2019-10-05 08:42:36 -06:00
|
|
|
&& !priorCapture)
|
2017-06-30 09:20:00 -06:00
|
|
|
update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth));
|
2015-10-12 15:00:54 -06:00
|
|
|
|
2018-01-28 06:40:07 -07:00
|
|
|
if (PvNode)
|
|
|
|
bestValue = std::min(bestValue, maxValue);
|
|
|
|
|
Add / remove leaves from search tree ttPv
add if previous leaf is in search tree and we didn't find a counter move
else remove the position if the leaf is the last one in search tree.
STC : https://tests.stockfishchess.org/tests/view/5f49203c3def640786115314
LLR: 2.95 (-2.94,2.94) {-0.25,1.25}
Total: 29968 W: 3381 L: 3195 D: 23392
Ptnml(0-2): 146, 2432, 9671, 2560, 175
LTC : https://tests.stockfishchess.org/tests/view/5f494bea3def640786115336
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 84952 W: 4619 L: 4333 D: 76000
Ptnml(0-2): 86, 3765, 34481, 4065, 79
closes https://github.com/official-stockfish/Stockfish/pull/3075
Bench 3527337
2020-08-28 04:06:36 -06:00
|
|
|
// If no good move is found and the previous position was ttPv, then the previous
|
|
|
|
// opponent move is probably good and the new position is added to the search tree.
|
|
|
|
if (bestValue <= alpha)
|
|
|
|
ss->ttPv = ss->ttPv || ((ss-1)->ttPv && depth > 3);
|
|
|
|
// Otherwise, a counter move has been found and if the position is the last leaf
|
|
|
|
// in the search tree, remove the position from the search tree.
|
|
|
|
else if (depth > 3)
|
|
|
|
ss->ttPv = ss->ttPv && (ss+1)->ttPv;
|
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// Write gathered information in transposition table
|
2020-02-24 15:32:17 -07:00
|
|
|
if (!excludedMove && !(rootNode && thisThread->pvIdx))
|
Add / remove leaves from search tree ttPv
add if previous leaf is in search tree and we didn't find a counter move
else remove the position if the leaf is the last one in search tree.
STC : https://tests.stockfishchess.org/tests/view/5f49203c3def640786115314
LLR: 2.95 (-2.94,2.94) {-0.25,1.25}
Total: 29968 W: 3381 L: 3195 D: 23392
Ptnml(0-2): 146, 2432, 9671, 2560, 175
LTC : https://tests.stockfishchess.org/tests/view/5f494bea3def640786115336
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 84952 W: 4619 L: 4333 D: 76000
Ptnml(0-2): 86, 3765, 34481, 4065, 79
closes https://github.com/official-stockfish/Stockfish/pull/3075
Bench 3527337
2020-08-28 04:06:36 -06:00
|
|
|
tte->save(posKey, value_to_tt(bestValue, ss->ply), ss->ttPv,
|
2017-04-22 01:03:17 -06:00
|
|
|
bestValue >= beta ? BOUND_LOWER :
|
|
|
|
PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER,
|
2019-03-29 07:05:02 -06:00
|
|
|
depth, bestMove, ss->staticEval);
|
2010-05-08 02:54:51 -06:00
|
|
|
|
2009-03-22 07:49:18 -06:00
|
|
|
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
|
|
|
|
|
2008-08-31 23:59:13 -06:00
|
|
|
return bestValue;
|
|
|
|
}
|
2008-09-03 15:33:49 -06:00
|
|
|
|
2011-12-10 11:14:13 -07:00
|
|
|
|
2019-03-31 04:02:19 -06:00
|
|
|
// qsearch() is the quiescence search function, which is called by the main search
|
|
|
|
// function with zero depth, or recursively with further decreasing depth per call.
|
2018-03-13 01:10:59 -06:00
|
|
|
template <NodeType NT>
|
2011-12-04 03:46:31 -07:00
|
|
|
Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth) {
|
2008-08-31 23:59:13 -06:00
|
|
|
|
Renaming some variables in code
Implements renaming suggestions by Marco Costalba, Günther Demetz,
Gontran Lemaire, Ronald de Man, Stéphane Nicolet, Alain Savard,
Joost VandeVondele, Jerry Donald Watson, Mike Whiteley, xoto10,
and I hope that I haven't forgotten anybody.
Perpetual renaming thread for suggestions:
https://github.com/official-stockfish/Stockfish/issues/1426
No functional change.
2018-03-15 03:44:26 -06:00
|
|
|
constexpr bool PvNode = NT == PV;
|
2011-05-28 05:13:42 -06:00
|
|
|
|
2011-12-26 17:00:44 -07:00
|
|
|
assert(alpha >= -VALUE_INFINITE && alpha < beta && beta <= VALUE_INFINITE);
|
2012-10-07 01:34:04 -06:00
|
|
|
assert(PvNode || (alpha == beta - 1));
|
2019-09-28 14:27:23 -06:00
|
|
|
assert(depth <= 0);
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2014-11-18 03:57:57 -07:00
|
|
|
Move pv[MAX_PLY+1];
|
2009-11-05 03:11:02 -07:00
|
|
|
StateInfo st;
|
2021-04-19 11:50:19 -06:00
|
|
|
ASSERT_ALIGNED(&st, Eval::NNUE::CacheLineSize);
|
2020-11-03 03:23:35 -07:00
|
|
|
|
2014-12-13 00:16:35 -07:00
|
|
|
TTEntry* tte;
|
2012-10-07 01:34:04 -06:00
|
|
|
Key posKey;
|
|
|
|
Move ttMove, move, bestMove;
|
2018-02-12 14:57:42 -07:00
|
|
|
Depth ttDepth;
|
2012-12-15 03:11:38 -07:00
|
|
|
Value bestValue, value, ttValue, futilityValue, futilityBase, oldAlpha;
|
Adjust penalty on refuted early quiet moves
This patch changes how previous early moves are penalized in case
search finds a best move. Here, the first quiet move that was not
a transposition table move is penalized.
passed STC
https://tests.stockfishchess.org/tests/view/5f51d839ba100690c5cc5f69
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 10088 W: 1150 L: 997 D: 7941
Ptnml(0-2): 41, 772, 3278, 899, 54
passed LTC
https://tests.stockfishchess.org/tests/view/5f51e435ba100690c5cc5f76
LLR: 2.93 (-2.94,2.94) {0.25,1.25}
Total: 30808 W: 1564 L: 1405 D: 27839
Ptnml(0-2): 19, 1245, 12717, 1404, 19
closes https://github.com/official-stockfish/Stockfish/pull/3106
bench 3983758
2020-09-04 06:53:59 -06:00
|
|
|
bool pvHit, givesCheck, captureOrPromotion;
|
2017-05-21 19:25:20 -06:00
|
|
|
int moveCount;
|
2009-11-05 03:11:02 -07:00
|
|
|
|
2014-11-18 03:57:57 -07:00
|
|
|
if (PvNode)
|
|
|
|
{
|
|
|
|
oldAlpha = alpha; // To flag BOUND_EXACT when eval above alpha and no available moves
|
|
|
|
(ss+1)->pv = pv;
|
|
|
|
ss->pv[0] = MOVE_NONE;
|
2014-11-12 14:13:55 -07:00
|
|
|
}
|
|
|
|
|
2018-07-19 10:26:05 -06:00
|
|
|
Thread* thisThread = pos.this_thread();
|
Let ss->ply denote the number of plies from the root to the current node
This patch lets ss->ply be equal to 0 at the root of the search.
Currently, the root has ss->ply == 1, which is less intuitive:
- Setting the rootNode bool has to check (ss-1)->ply == 0.
- All mate values are off by one: the code seems to assume that mated-in-0
is -VALUE_MATE, mate-1-in-ply is VALUE_MATE-1, mated-in-2-ply is VALUE_MATE+2, etc.
But the mate_in() and mated_in() functions are called with ss->ply, which is 1 in
at the root.
- The is_draw() function currently needs to explain why it has "ply - 1 > i" instead
of simply "ply > i".
- The ss->ply >= MAX_PLY tests in search() and qsearch() already assume that
ss->ply == 0 at the root. If we start at ss->ply == 1, it would make more sense to
go up to and including ss->ply == MAX_PLY, so stop at ss->ply > MAX_PLY. See also
the asserts testing for 0 <= ss->ply && ss->ply < MAX_PLY.
The reason for ss->ply == 1 at the root is the line "ss->ply = (ss-1)->ply + 1" at
the start for search() and qsearch(). By replacing this with "(ss+1)->ply = ss->ply + 1"
we keep ss->ply == 0 at the root. Note that search() already clears killers in (ss+2),
so there is no danger in accessing ss+1.
I have NOT changed pv[MAX_PLY + 1] to pv[MAX_PLY + 2] in search() and qsearch().
It seems to me that MAX_PLY + 1 is exactly right:
- MAX_PLY entries for ss->ply running from 0 to MAX_PLY-1, and 1 entry for the
final MOVE_NONE.
I have verified that mate scores are reported correctly. (They were already reported
correctly due to the extra ply being rounded down when converting to moves.)
The value of seldepth output to the user should probably not change, so I add 1 to it.
(Humans count from 1, computers from 0.)
A small optimisation I did not include: instead of setting ss->ply in every invocation
of search() and qsearch(), it could be set once for all plies at the start of
Thread::search(). This saves a couple of instructions per node.
No functional change (unless the search searches a branch MAX_PLY deep), so bench
does not change.
2017-09-16 13:49:29 -06:00
|
|
|
(ss+1)->ply = ss->ply + 1;
|
2019-04-13 09:17:47 -06:00
|
|
|
bestMove = MOVE_NONE;
|
continuation histories when in check
If in check, don't write to continuation histories ss-4, ss-6.
Adding inCheck to the stack was needed, and might be useful for
future patches.
Passed STC:
https://tests.stockfishchess.org/tests/view/5e9ee24acaaff5d60a50b812
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 61774 W: 11725 L: 11449 D: 38600
Ptnml(0-2): 971, 7211, 14322, 7337, 1046
Passed LTC:
https://tests.stockfishchess.org/tests/view/5e9eecb7caaff5d60a50b831
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 250822 W: 32067 L: 31179 D: 187576
Ptnml(0-2): 1745, 23126, 74824, 23928, 1788
closes https://github.com/official-stockfish/Stockfish/pull/2645
bench: 4808463
2020-04-21 12:55:41 -06:00
|
|
|
ss->inCheck = pos.checkers();
|
2017-05-21 19:25:20 -06:00
|
|
|
moveCount = 0;
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2018-02-12 14:57:42 -07:00
|
|
|
// Check for an immediate draw or maximum ply reached
|
|
|
|
if ( pos.is_draw(ss->ply)
|
|
|
|
|| ss->ply >= MAX_PLY)
|
continuation histories when in check
If in check, don't write to continuation histories ss-4, ss-6.
Adding inCheck to the stack was needed, and might be useful for
future patches.
Passed STC:
https://tests.stockfishchess.org/tests/view/5e9ee24acaaff5d60a50b812
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 61774 W: 11725 L: 11449 D: 38600
Ptnml(0-2): 971, 7211, 14322, 7337, 1046
Passed LTC:
https://tests.stockfishchess.org/tests/view/5e9eecb7caaff5d60a50b831
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 250822 W: 32067 L: 31179 D: 187576
Ptnml(0-2): 1745, 23126, 74824, 23928, 1788
closes https://github.com/official-stockfish/Stockfish/pull/2645
bench: 4808463
2020-04-21 12:55:41 -06:00
|
|
|
return (ss->ply >= MAX_PLY && !ss->inCheck) ? evaluate(pos) : VALUE_DRAW;
|
Cleanup MAX_PLY
This area has become obscure and tricky over the course of incremental
changes that did not respect the original's consistency and clarity. Now,
it's not clear why we use MAX_PLY = 120, or why we use MAX_PLY+6, among
other things.
This patch does the following:
* ID loop: depth ranges from 1 to MAX_PLY-1, and due to TT constraint (depth
must fit into an int8_t), MAX_PLY should be 128.
* stack[]: plies now range from 0 to MAX_PLY-1, hence stack[MAX_PLY+4],
because of the extra 2+2 padding elements (for ss-2 and ss+2). Document this
better, while we're at it.
* Enforce 0 <= ply < MAX_PLY:
- stop condition is now ss->ply >= MAX_PLY and not ss->ply > MAX_PLY.
- assert(ss->ply < MAX_PLY), before using ss+1 and ss+2.
- as a result, we don't need the artificial MAX_PLY+6 range. Instead we
can use MAX_PLY+4 and it's clear why (for ss-2 and ss+2).
* fix: extract_pv_from_tt() and insert_pv_in_tt() had no reason to use
MAX_PLY_PLUS_6, because the array is indexed by plies, so the range of
available plies applies (0..MAX_PLY before, and now 0..MAX_PLY-1).
Tested with debug compile, using MAX_PLY=16, and running bench at depth 17,
using 1 and 7 threads. No assert() fired. Feel free to submit to more severe
crash-tests, if you can think of any.
No functional change.
2014-11-03 08:36:24 -07:00
|
|
|
|
|
|
|
assert(0 <= ss->ply && ss->ply < MAX_PLY);
|
2011-07-19 20:31:50 -06:00
|
|
|
|
2013-12-02 11:04:09 -07:00
|
|
|
// Decide whether or not to include checks: this fixes also the type of
|
2013-03-11 08:18:15 -06:00
|
|
|
// TT entry depth that we are going to use. Note that in qsearch we use
|
|
|
|
// only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS.
|
continuation histories when in check
If in check, don't write to continuation histories ss-4, ss-6.
Adding inCheck to the stack was needed, and might be useful for
future patches.
Passed STC:
https://tests.stockfishchess.org/tests/view/5e9ee24acaaff5d60a50b812
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 61774 W: 11725 L: 11449 D: 38600
Ptnml(0-2): 971, 7211, 14322, 7337, 1046
Passed LTC:
https://tests.stockfishchess.org/tests/view/5e9eecb7caaff5d60a50b831
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 250822 W: 32067 L: 31179 D: 187576
Ptnml(0-2): 1745, 23126, 74824, 23928, 1788
closes https://github.com/official-stockfish/Stockfish/pull/2645
bench: 4808463
2020-04-21 12:55:41 -06:00
|
|
|
ttDepth = ss->inCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS
|
2013-03-11 08:18:15 -06:00
|
|
|
: DEPTH_QS_NO_CHECKS;
|
2013-06-30 05:12:04 -06:00
|
|
|
// Transposition table lookup
|
2012-10-07 01:34:04 -06:00
|
|
|
posKey = pos.key();
|
Adjust penalty on refuted early quiet moves
This patch changes how previous early moves are penalized in case
search finds a best move. Here, the first quiet move that was not
a transposition table move is penalized.
passed STC
https://tests.stockfishchess.org/tests/view/5f51d839ba100690c5cc5f69
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 10088 W: 1150 L: 997 D: 7941
Ptnml(0-2): 41, 772, 3278, 899, 54
passed LTC
https://tests.stockfishchess.org/tests/view/5f51e435ba100690c5cc5f76
LLR: 2.93 (-2.94,2.94) {0.25,1.25}
Total: 30808 W: 1564 L: 1405 D: 27839
Ptnml(0-2): 19, 1245, 12717, 1404, 19
closes https://github.com/official-stockfish/Stockfish/pull/3106
bench 3983758
2020-09-04 06:53:59 -06:00
|
|
|
tte = TT.probe(posKey, ss->ttHit);
|
|
|
|
ttValue = ss->ttHit ? value_from_tt(tte->value(), ss->ply, pos.rule50_count()) : VALUE_NONE;
|
|
|
|
ttMove = ss->ttHit ? tte->move() : MOVE_NONE;
|
|
|
|
pvHit = ss->ttHit && tte->is_pv();
|
2012-10-07 01:34:04 -06:00
|
|
|
|
2014-11-18 03:57:57 -07:00
|
|
|
if ( !PvNode
|
Adjust penalty on refuted early quiet moves
This patch changes how previous early moves are penalized in case
search finds a best move. Here, the first quiet move that was not
a transposition table move is penalized.
passed STC
https://tests.stockfishchess.org/tests/view/5f51d839ba100690c5cc5f69
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 10088 W: 1150 L: 997 D: 7941
Ptnml(0-2): 41, 772, 3278, 899, 54
passed LTC
https://tests.stockfishchess.org/tests/view/5f51e435ba100690c5cc5f76
LLR: 2.93 (-2.94,2.94) {0.25,1.25}
Total: 30808 W: 1564 L: 1405 D: 27839
Ptnml(0-2): 19, 1245, 12717, 1404, 19
closes https://github.com/official-stockfish/Stockfish/pull/3106
bench 3983758
2020-09-04 06:53:59 -06:00
|
|
|
&& ss->ttHit
|
2012-12-15 03:11:38 -07:00
|
|
|
&& tte->depth() >= ttDepth
|
|
|
|
&& ttValue != VALUE_NONE // Only in case of TT access race
|
2018-07-16 14:53:50 -06:00
|
|
|
&& (ttValue >= beta ? (tte->bound() & BOUND_LOWER)
|
|
|
|
: (tte->bound() & BOUND_UPPER)))
|
2012-12-15 03:11:38 -07:00
|
|
|
return ttValue;
|
2008-09-08 23:37:46 -06:00
|
|
|
|
2009-11-28 03:52:13 -07:00
|
|
|
// Evaluate the position statically
|
continuation histories when in check
If in check, don't write to continuation histories ss-4, ss-6.
Adding inCheck to the stack was needed, and might be useful for
future patches.
Passed STC:
https://tests.stockfishchess.org/tests/view/5e9ee24acaaff5d60a50b812
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 61774 W: 11725 L: 11449 D: 38600
Ptnml(0-2): 971, 7211, 14322, 7337, 1046
Passed LTC:
https://tests.stockfishchess.org/tests/view/5e9eecb7caaff5d60a50b831
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 250822 W: 32067 L: 31179 D: 187576
Ptnml(0-2): 1745, 23126, 74824, 23928, 1788
closes https://github.com/official-stockfish/Stockfish/pull/2645
bench: 4808463
2020-04-21 12:55:41 -06:00
|
|
|
if (ss->inCheck)
|
2010-05-22 02:56:46 -06:00
|
|
|
{
|
2013-11-08 03:42:22 -07:00
|
|
|
ss->staticEval = VALUE_NONE;
|
2010-06-03 11:29:48 -06:00
|
|
|
bestValue = futilityBase = -VALUE_INFINITE;
|
2010-05-22 02:56:46 -06:00
|
|
|
}
|
2009-03-24 08:48:14 -06:00
|
|
|
else
|
2010-01-21 08:58:00 -07:00
|
|
|
{
|
Adjust penalty on refuted early quiet moves
This patch changes how previous early moves are penalized in case
search finds a best move. Here, the first quiet move that was not
a transposition table move is penalized.
passed STC
https://tests.stockfishchess.org/tests/view/5f51d839ba100690c5cc5f69
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 10088 W: 1150 L: 997 D: 7941
Ptnml(0-2): 41, 772, 3278, 899, 54
passed LTC
https://tests.stockfishchess.org/tests/view/5f51e435ba100690c5cc5f76
LLR: 2.93 (-2.94,2.94) {0.25,1.25}
Total: 30808 W: 1564 L: 1405 D: 27839
Ptnml(0-2): 19, 1245, 12717, 1404, 19
closes https://github.com/official-stockfish/Stockfish/pull/3106
bench 3983758
2020-09-04 06:53:59 -06:00
|
|
|
if (ss->ttHit)
|
2012-12-27 04:13:31 -07:00
|
|
|
{
|
2019-06-09 07:07:36 -06:00
|
|
|
// Never assume anything about values stored in TT
|
2015-01-09 04:35:44 -07:00
|
|
|
if ((ss->staticEval = bestValue = tte->eval()) == VALUE_NONE)
|
2014-06-06 01:35:34 -06:00
|
|
|
ss->staticEval = bestValue = evaluate(pos);
|
2013-10-07 01:10:48 -06:00
|
|
|
|
|
|
|
// Can ttValue be used as a better position evaluation?
|
2018-07-16 14:53:50 -06:00
|
|
|
if ( ttValue != VALUE_NONE
|
2017-07-27 03:14:18 -06:00
|
|
|
&& (tte->bound() & (ttValue > bestValue ? BOUND_LOWER : BOUND_UPPER)))
|
|
|
|
bestValue = ttValue;
|
2012-12-27 04:13:31 -07:00
|
|
|
}
|
2012-12-01 10:06:29 -07:00
|
|
|
else
|
2020-12-01 05:02:35 -07:00
|
|
|
// In case of null move search use previous static eval with a different sign
|
|
|
|
// and addition of two tempos
|
2014-06-06 03:12:05 -06:00
|
|
|
ss->staticEval = bestValue =
|
2015-10-23 23:27:24 -06:00
|
|
|
(ss-1)->currentMove != MOVE_NULL ? evaluate(pos)
|
Remove Tempo
The Tempo variable was introduced 10 years ago in our search because the
classical evaluation function was antisymmetrical in White and Black by design
to gain speed:
Eval(White to play) = -Eval(Black to play)
Nowadays our neural networks know which side is to play in a position when
they evaluate a position and are trained on real games, so the neural network
encodes the advantage of moving as an output of search. This patch shows that
the Tempo variable is not necessary anymore.
STC:
LLR: 2.94 (-2.94,2.94) <-2.50,0.50>
Total: 33512 W: 2805 L: 2709 D: 27998
Ptnml(0-2): 80, 2209, 12095, 2279, 93
https://tests.stockfishchess.org/tests/view/60a44ceace8ea25a3ef03d30
LTC:
LLR: 2.95 (-2.94,2.94) <-2.50,0.50>
Total: 53920 W: 1807 L: 1760 D: 50353
Ptnml(0-2): 16, 1617, 23650, 1658, 19
https://tests.stockfishchess.org/tests/view/60a477f0ce8ea25a3ef03d49
We also tried a match (20000 games) at STC using purely classical, result was neutral:
https://tests.stockfishchess.org/tests/view/60a4eebcce8ea25a3ef03db5
Note: there are two locations left in search.cpp where we assume antisymmetry
of evaluation (in relation with a speed optimization for null moves in lines
770 and 1439), but as the values are just used for heuristic pruning this
approximation should not hurt too much because the order of magnitude is still
true most of the time.
closes https://github.com/official-stockfish/Stockfish/pull/3481
Bench: 4015864
2021-05-18 17:24:51 -06:00
|
|
|
: -(ss-1)->staticEval;
|
2010-01-21 08:58:00 -07:00
|
|
|
|
2010-06-03 11:29:48 -06:00
|
|
|
// Stand pat. Return immediately if static value is at least beta
|
|
|
|
if (bestValue >= beta)
|
|
|
|
{
|
2020-12-01 05:02:35 -07:00
|
|
|
// Save gathered info in transposition table
|
Adjust penalty on refuted early quiet moves
This patch changes how previous early moves are penalized in case
search finds a best move. Here, the first quiet move that was not
a transposition table move is penalized.
passed STC
https://tests.stockfishchess.org/tests/view/5f51d839ba100690c5cc5f69
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 10088 W: 1150 L: 997 D: 7941
Ptnml(0-2): 41, 772, 3278, 899, 54
passed LTC
https://tests.stockfishchess.org/tests/view/5f51e435ba100690c5cc5f76
LLR: 2.93 (-2.94,2.94) {0.25,1.25}
Total: 30808 W: 1564 L: 1405 D: 27839
Ptnml(0-2): 19, 1245, 12717, 1404, 19
closes https://github.com/official-stockfish/Stockfish/pull/3106
bench 3983758
2020-09-04 06:53:59 -06:00
|
|
|
if (!ss->ttHit)
|
2020-03-01 01:31:17 -07:00
|
|
|
tte->save(posKey, value_to_tt(bestValue, ss->ply), false, BOUND_LOWER,
|
2018-07-03 16:58:16 -06:00
|
|
|
DEPTH_NONE, MOVE_NONE, ss->staticEval);
|
2010-06-04 01:46:38 -06:00
|
|
|
|
2010-06-03 11:29:48 -06:00
|
|
|
return bestValue;
|
|
|
|
}
|
2009-03-27 08:30:45 -06:00
|
|
|
|
2010-06-03 11:29:48 -06:00
|
|
|
if (PvNode && bestValue > alpha)
|
|
|
|
alpha = bestValue;
|
2008-09-07 00:31:30 -06:00
|
|
|
|
Assorted search and eval parameter tune
Search and eval parameter tune.
STC https://tests.stockfishchess.org/tests/view/5fba850a67cbf42301d6b07d
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 24312 W: 2388 L: 2228 D: 19696
Ptnml(0-2): 85, 1800, 8241, 1930, 100
LTC https://tests.stockfishchess.org/tests/view/5fbad5ea67cbf42301d6b0fa
LLR: 2.95 (-2.94,2.94) {0.25,1.25}
Total: 88376 W: 3619 L: 3351 D: 81406
Ptnml(0-2): 56, 2977, 37849, 3255, 51
closes https://github.com/official-stockfish/Stockfish/pull/3232
bench: 3600361
2020-11-24 09:06:30 -07:00
|
|
|
futilityBase = bestValue + 155;
|
2010-06-03 11:29:48 -06:00
|
|
|
}
|
2010-01-19 07:24:26 -07:00
|
|
|
|
2019-02-27 13:25:12 -07:00
|
|
|
const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory,
|
2019-10-18 07:23:00 -06:00
|
|
|
nullptr , (ss-4)->continuationHistory,
|
|
|
|
nullptr , (ss-6)->continuationHistory };
|
2018-07-19 10:26:05 -06:00
|
|
|
|
2008-08-31 23:59:13 -06:00
|
|
|
// Initialize a MovePicker object for the current position, and prepare
|
2010-01-19 07:24:26 -07:00
|
|
|
// to search the moves. Because the depth is <= 0 here, only captures,
|
Simplify make_promotions()
Remove special case handling of QUIET_CHECKS in make_promotions()
STC https://tests.stockfishchess.org/tests/view/5f055dbb59f6f035328945fb
LLR: 2.98 (-2.94,2.94) {-1.50,0.50}
Total: 42808 W: 8177 L: 8054 D: 26577
Ptnml(0-2): 665, 4890, 10201, 4953, 695
LTC https://tests.stockfishchess.org/tests/view/5f06231a59f6f03532894661
LLR: 2.96 (-2.94,2.94) {-1.50,0.50}
Total: 9616 W: 1214 L: 1111 D: 7291
Ptnml(0-2): 53, 821, 2965, 908, 61
closes https://github.com/official-stockfish/Stockfish/pull/2800
Bench: 4576410
2020-07-05 16:17:04 -06:00
|
|
|
// queen and checking knight promotions, and other checks(only if depth >= DEPTH_QS_CHECKS)
|
|
|
|
// will be generated.
|
2018-07-19 10:26:05 -06:00
|
|
|
MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory,
|
|
|
|
&thisThread->captureHistory,
|
|
|
|
contHist,
|
2018-04-28 22:48:18 -06:00
|
|
|
to_sq((ss-1)->currentMove));
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2010-03-24 03:15:00 -06:00
|
|
|
// Loop through the moves until no moves remain or a beta cutoff occurs
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
while ((move = mp.next_move()) != MOVE_NONE)
|
2008-09-07 00:31:30 -06:00
|
|
|
{
|
2011-10-03 02:56:49 -06:00
|
|
|
assert(is_ok(move));
|
2008-09-07 00:31:30 -06:00
|
|
|
|
2019-03-31 02:44:55 -06:00
|
|
|
givesCheck = pos.gives_check(move);
|
2019-10-18 07:23:00 -06:00
|
|
|
captureOrPromotion = pos.capture_or_promotion(move);
|
2010-01-08 03:45:46 -07:00
|
|
|
|
2017-05-21 19:25:20 -06:00
|
|
|
moveCount++;
|
|
|
|
|
Change advanced pawn push threshold
A pawn push is now considered to be "advanced" if the relative destination
rank is > 6 (previously it was > 5). This affects the search heuristic.
Also remove an assert concerning en passant moves in qsearch().
STC:
LLR: 2.97 (-2.94,2.94) {-0.25,1.25}
Total: 46744 W: 4224 L: 4040 D: 38480
Ptnml(0-2): 165, 3206, 16451, 3380, 170
https://tests.stockfishchess.org/tests/view/604746082433018de7a3872e
LTC:
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 107840 W: 4198 L: 3892 D: 99750
Ptnml(0-2): 58, 3472, 46557, 3772, 61
https://tests.stockfishchess.org/tests/view/60475eae2433018de7a38737
Closes https://github.com/official-stockfish/Stockfish/pull/3389
Bench: 4796780
2021-03-08 11:46:41 -07:00
|
|
|
// Futility pruning and moveCount pruning
|
Qsearch pruning: follow-up
This is a follow-up of the recent qsearch pruning patch in
https://github.com/official-stockfish/Stockfish/commit/a260c9a8a24a2630a900efc3821000c3481b0c5d
We now use the same guard condition (testing that we already have a defense with
a score better score than a TB loss) for all pruning heuristics in qsearch().
This allows some pruning when in check, but in a controlled way to ensure that
no wrong mate scores appear.
Tested with Elo-gaining bounds:
STC:
LLR: 2.97 (-2.94,2.94) {-0.25,1.25}
Total: 22632 W: 2433 L: 2264 D: 17935
Ptnml(0-2): 98, 1744, 7487, 1865, 122
https://tests.stockfishchess.org/tests/view/5fa59405936c54e11ec99515
LTC:
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 105432 W: 4965 L: 4648 D: 95819
Ptnml(0-2): 85, 4110, 44011, 4423, 87
https://tests.stockfishchess.org/tests/view/5fa5b609936c54e11ec9952a
closes https://github.com/official-stockfish/Stockfish/pull/3221
Bench: 3578092
2020-11-06 11:20:27 -07:00
|
|
|
if ( bestValue > VALUE_TB_LOSS_IN_MAX_PLY
|
2011-04-29 08:26:48 -06:00
|
|
|
&& !givesCheck
|
2013-08-24 02:05:48 -06:00
|
|
|
&& futilityBase > -VALUE_KNOWN_WIN
|
Remove advanced_pawn_push()
Continuation of work by @topologist: we now do futility pruning and movecount
pruning in qsearch() for pawn pushes up to the 7th rank. So the condition to
avoid the pruning is if the move is a promotion or not. This allows to get rid
of the advanced_pawn_push() function in position.h alltogether.
Passed STC
https://tests.stockfishchess.org/tests/view/6048c5842433018de7a387e6
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 34424 W: 3081 L: 3015 D: 28328
Ptnml(0-2): 110, 2442, 12052, 2488, 120
Passed LTC
https://tests.stockfishchess.org/tests/view/6048f7d22433018de7a387f0
LLR: 2.94 (-2.94,2.94) {-0.75,0.25}
Total: 142024 W: 5170 L: 5202 D: 131652
Ptnml(0-2): 50, 4678, 61613, 4596, 75
Closes https://github.com/official-stockfish/Stockfish/pull/3390
Bench: 4339126
2021-03-11 04:51:20 -07:00
|
|
|
&& type_of(move) != PROMOTION)
|
2008-09-07 00:31:30 -06:00
|
|
|
{
|
2013-12-04 08:49:01 -07:00
|
|
|
|
Simplify MCP in QS
Simplify moveCount pruning in QS by removing depth dependency.
STC
LLR: 2.94 (-2.94,2.94) {-1.25,0.25}
Total: 42960 W: 4741 L: 4661 D: 33558
Ptnml(0-2): 218, 3574, 13804, 3678, 206
https://tests.stockfishchess.org/tests/view/5f42e3f75089a564a10d8493
LTC
LLR: 2.94 (-2.94,2.94) {-0.75,0.25}
Total: 66672 W: 3563 L: 3508 D: 59601
Ptnml(0-2): 71, 3064, 26996, 3149, 56
https://tests.stockfishchess.org/tests/view/5f4353285089a564a10d84d0
closes https://github.com/official-stockfish/Stockfish/pull/3067
Bench: 4074430
2020-08-25 07:10:47 -06:00
|
|
|
if (moveCount > 2)
|
Introduce movecount pruning for qsearch()
If in quiescence search, we assume that me can prune late moves when:
a) the move ordering count of the move is : moveCount > abs(depth) + 2
b) we are not in check
c) the late move does not give check
d) the late move is not an advanced pawn push
Modification of an original idea by @VoyagerOne.
STC
https://tests.stockfishchess.org/tests/view/5f40581787a5c3c63d8f535f
LLR: 2.96 (-2.94,2.94) {-0.25,1.25}
Total: 132848 W: 14999 L: 14661 D: 103188
Ptnml(0-2): 684, 11242, 42309, 11430, 759
LTC
https://tests.stockfishchess.org/tests/view/5f4226da87a5c3c63d8f5412
LLR: 2.98 (-2.94,2.94) {0.25,1.25}
Total: 12008 W: 678 L: 551 D: 10779
Ptnml(0-2): 8, 485, 4899, 596, 16
closes https://github.com/official-stockfish/Stockfish/pull/3053
Bench: 3749974
2020-08-23 05:22:32 -06:00
|
|
|
continue;
|
|
|
|
|
2013-12-04 08:49:01 -07:00
|
|
|
futilityValue = futilityBase + PieceValue[EG][pos.piece_on(to_sq(move))];
|
2008-09-07 00:31:30 -06:00
|
|
|
|
2015-01-14 13:18:41 -07:00
|
|
|
if (futilityValue <= alpha)
|
2008-09-07 00:31:30 -06:00
|
|
|
{
|
2012-11-26 08:13:36 -07:00
|
|
|
bestValue = std::max(bestValue, futilityValue);
|
2008-09-07 00:31:30 -06:00
|
|
|
continue;
|
|
|
|
}
|
2011-02-22 15:23:45 -07:00
|
|
|
|
2016-10-06 11:55:10 -06:00
|
|
|
if (futilityBase <= alpha && !pos.see_ge(move, VALUE_ZERO + 1))
|
2012-11-26 08:13:36 -07:00
|
|
|
{
|
|
|
|
bestValue = std::max(bestValue, futilityBase);
|
2011-02-22 15:23:45 -07:00
|
|
|
continue;
|
2012-11-26 08:13:36 -07:00
|
|
|
}
|
2008-08-31 23:59:13 -06:00
|
|
|
}
|
|
|
|
|
2020-06-24 14:19:58 -06:00
|
|
|
// Do not search moves with negative SEE values
|
Qsearch pruning: follow-up
This is a follow-up of the recent qsearch pruning patch in
https://github.com/official-stockfish/Stockfish/commit/a260c9a8a24a2630a900efc3821000c3481b0c5d
We now use the same guard condition (testing that we already have a defense with
a score better score than a TB loss) for all pruning heuristics in qsearch().
This allows some pruning when in check, but in a controlled way to ensure that
no wrong mate scores appear.
Tested with Elo-gaining bounds:
STC:
LLR: 2.97 (-2.94,2.94) {-0.25,1.25}
Total: 22632 W: 2433 L: 2264 D: 17935
Ptnml(0-2): 98, 1744, 7487, 1865, 122
https://tests.stockfishchess.org/tests/view/5fa59405936c54e11ec99515
LTC:
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 105432 W: 4965 L: 4648 D: 95819
Ptnml(0-2): 85, 4110, 44011, 4423, 87
https://tests.stockfishchess.org/tests/view/5fa5b609936c54e11ec9952a
closes https://github.com/official-stockfish/Stockfish/pull/3221
Bench: 3578092
2020-11-06 11:20:27 -07:00
|
|
|
if ( bestValue > VALUE_TB_LOSS_IN_MAX_PLY
|
Less pruning in qsearch
do not prune moves that give discovery checks, even if with negative SSE.
STC https://tests.stockfishchess.org/tests/view/5f4cb5e8ba100690c5cc5d25
LLR: 2.96 (-2.94,2.94) {-0.25,1.25}
Total: 91328 W: 9940 L: 9667 D: 71721
Ptnml(0-2): 491, 7345, 29693, 7670, 465
LTC https://tests.stockfishchess.org/tests/view/5f4dbc2eba100690c5cc5dac
LLR: 2.97 (-2.94,2.94) {0.25,1.25}
Total: 52448 W: 2799 L: 2586 D: 47063
Ptnml(0-2): 53, 2220, 21459, 2445, 47
closes https://github.com/official-stockfish/Stockfish/pull/3098
bench: 4031192
2020-09-02 08:45:49 -06:00
|
|
|
&& !pos.see_ge(move))
|
2008-09-07 00:31:30 -06:00
|
|
|
continue;
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2017-06-21 14:44:05 -06:00
|
|
|
// Speculative prefetch as early as possible
|
|
|
|
prefetch(TT.first_entry(pos.key_after(move)));
|
|
|
|
|
2013-12-02 11:04:09 -07:00
|
|
|
// Check for legality just before making the move
|
2016-07-03 02:35:44 -06:00
|
|
|
if (!pos.legal(move))
|
2017-05-21 19:25:20 -06:00
|
|
|
{
|
|
|
|
moveCount--;
|
2011-05-23 07:14:47 -06:00
|
|
|
continue;
|
2017-05-21 19:25:20 -06:00
|
|
|
}
|
2011-05-23 07:14:47 -06:00
|
|
|
|
2010-06-03 11:29:48 -06:00
|
|
|
ss->currentMove = move;
|
continuation histories when in check
If in check, don't write to continuation histories ss-4, ss-6.
Adding inCheck to the stack was needed, and might be useful for
future patches.
Passed STC:
https://tests.stockfishchess.org/tests/view/5e9ee24acaaff5d60a50b812
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 61774 W: 11725 L: 11449 D: 38600
Ptnml(0-2): 971, 7211, 14322, 7337, 1046
Passed LTC:
https://tests.stockfishchess.org/tests/view/5e9eecb7caaff5d60a50b831
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 250822 W: 32067 L: 31179 D: 187576
Ptnml(0-2): 1745, 23126, 74824, 23928, 1788
closes https://github.com/official-stockfish/Stockfish/pull/2645
bench: 4808463
2020-04-21 12:55:41 -06:00
|
|
|
ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck]
|
2019-10-18 07:23:00 -06:00
|
|
|
[captureOrPromotion]
|
|
|
|
[pos.moved_piece(move)]
|
|
|
|
[to_sq(move)];
|
2010-06-03 11:29:48 -06:00
|
|
|
|
2021-05-17 01:13:34 -06:00
|
|
|
// Continuation history based pruning
|
Introduce countermove based pruning for qsearch
This patch continues work of previous patch in introducing pruning heuristics in qsearch by analogy to main search, now with countermove based pruning.
Idea is that if move is late enough and is quite check (we do generate them in qsearch) and has bad enough countermove history - prune it.
passed STC
https://tests.stockfishchess.org/tests/view/5f41220287a5c3c63d8f53c5
LLR: 2.93 (-2.94,2.94) {-0.25,1.25}
Total: 35944 W: 4127 L: 3929 D: 27888
Ptnml(0-2): 196, 2970, 11459, 3134, 213
passed LTC
https://tests.stockfishchess.org/tests/view/5f41862f87a5c3c63d8f53e8
LLR: 2.95 (-2.94,2.94) {0.25,1.25}
Total: 138448 W: 7655 L: 7252 D: 123541
Ptnml(0-2): 145, 6247, 56043, 6638, 151
closes https://github.com/official-stockfish/Stockfish/pull/3058
Bench: 3610676
2020-08-23 23:04:16 -06:00
|
|
|
if ( !captureOrPromotion
|
Fix incorrect pruning in qsearch
Only do countermove based pruning in qsearch if we already have a move with a better score than a TB loss.
This patch fixes a bug (started as 843a961) that incorrectly prunes moves if in check,
and adds an assert to make sure no wrong mate scores are given in the future.
It replaces a no-op moveCount check with a check for bestValue.
Initially discussed in #3171 and later in #3199, #3198 and #3210.
This PR effectively closes #3171
It also likely fixes #3196 where this causes user visible incorrect TB scores,
which probably result from these incorrect mate scores.
Passed STC and LTC non-regression tests.
https://tests.stockfishchess.org/tests/view/5f9ef8dabca9bf35bae7f648
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 21672 W: 2339 L: 2230 D: 17103
Ptnml(0-2): 126, 1689, 7083, 1826, 112
https://tests.stockfishchess.org/tests/view/5f9f0caebca9bf35bae7f666
LLR: 2.97 (-2.94,2.94) {-0.75,0.25}
Total: 33152 W: 1551 L: 1485 D: 30116
Ptnml(0-2): 27, 1308, 13832, 1390, 19
closes https://github.com/official-stockfish/Stockfish/pull/3214
Bench: 3625915
2020-11-01 10:33:17 -07:00
|
|
|
&& bestValue > VALUE_TB_LOSS_IN_MAX_PLY
|
Introduce countermove based pruning for qsearch
This patch continues work of previous patch in introducing pruning heuristics in qsearch by analogy to main search, now with countermove based pruning.
Idea is that if move is late enough and is quite check (we do generate them in qsearch) and has bad enough countermove history - prune it.
passed STC
https://tests.stockfishchess.org/tests/view/5f41220287a5c3c63d8f53c5
LLR: 2.93 (-2.94,2.94) {-0.25,1.25}
Total: 35944 W: 4127 L: 3929 D: 27888
Ptnml(0-2): 196, 2970, 11459, 3134, 213
passed LTC
https://tests.stockfishchess.org/tests/view/5f41862f87a5c3c63d8f53e8
LLR: 2.95 (-2.94,2.94) {0.25,1.25}
Total: 138448 W: 7655 L: 7252 D: 123541
Ptnml(0-2): 145, 6247, 56043, 6638, 151
closes https://github.com/official-stockfish/Stockfish/pull/3058
Bench: 3610676
2020-08-23 23:04:16 -06:00
|
|
|
&& (*contHist[0])[pos.moved_piece(move)][to_sq(move)] < CounterMovePruneThreshold
|
|
|
|
&& (*contHist[1])[pos.moved_piece(move)][to_sq(move)] < CounterMovePruneThreshold)
|
|
|
|
continue;
|
|
|
|
|
2009-11-05 03:11:02 -07:00
|
|
|
// Make and search the move
|
Compute checkers from scratch
This micro-optimization only complicates the code and provides no benefit.
Removing it is even a speedup on my machine (i7-3770k, linux, gcc 4.9.1):
stat test master diff
mean 2,403,118 2,390,904 12,214
stdev 12,043 10,620 3,677
speedup 0.51%
P(speedup>0) 100.0%
No functional change.
2015-02-15 00:49:20 -07:00
|
|
|
pos.do_move(move, st, givesCheck);
|
2019-09-28 14:27:23 -06:00
|
|
|
value = -qsearch<NT>(pos, ss+1, -beta, -alpha, depth - 1);
|
2009-02-22 09:49:52 -07:00
|
|
|
pos.undo_move(move);
|
2008-08-31 23:59:13 -06:00
|
|
|
|
|
|
|
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
|
|
|
|
|
2016-01-16 14:34:29 -07:00
|
|
|
// Check for a new best move
|
2008-09-07 00:31:30 -06:00
|
|
|
if (value > bestValue)
|
|
|
|
{
|
|
|
|
bestValue = value;
|
2011-08-07 03:29:47 -06:00
|
|
|
|
2012-10-07 01:34:04 -06:00
|
|
|
if (value > alpha)
|
|
|
|
{
|
2018-11-25 03:27:40 -07:00
|
|
|
bestMove = move;
|
|
|
|
|
2014-11-21 01:10:52 -07:00
|
|
|
if (PvNode) // Update pv even in fail-high case
|
2014-11-18 03:57:57 -07:00
|
|
|
update_pv(ss->pv, move, (ss+1)->pv);
|
2014-11-12 14:13:55 -07:00
|
|
|
|
2015-10-23 23:27:24 -06:00
|
|
|
if (PvNode && value < beta) // Update alpha here!
|
2012-10-07 01:34:04 -06:00
|
|
|
alpha = value;
|
2018-11-25 03:27:40 -07:00
|
|
|
else
|
|
|
|
break; // Fail high
|
2012-10-07 01:34:04 -06:00
|
|
|
}
|
2008-09-07 00:31:30 -06:00
|
|
|
}
|
2008-08-31 23:59:13 -06:00
|
|
|
}
|
|
|
|
|
2020-06-24 14:19:58 -06:00
|
|
|
// All legal moves have been searched. A special case: if we're in check
|
2009-06-11 07:57:42 -06:00
|
|
|
// and no legal moves were found, it is checkmate.
|
continuation histories when in check
If in check, don't write to continuation histories ss-4, ss-6.
Adding inCheck to the stack was needed, and might be useful for
future patches.
Passed STC:
https://tests.stockfishchess.org/tests/view/5e9ee24acaaff5d60a50b812
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 61774 W: 11725 L: 11449 D: 38600
Ptnml(0-2): 971, 7211, 14322, 7337, 1046
Passed LTC:
https://tests.stockfishchess.org/tests/view/5e9eecb7caaff5d60a50b831
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 250822 W: 32067 L: 31179 D: 187576
Ptnml(0-2): 1745, 23126, 74824, 23928, 1788
closes https://github.com/official-stockfish/Stockfish/pull/2645
bench: 4808463
2020-04-21 12:55:41 -06:00
|
|
|
if (ss->inCheck && bestValue == -VALUE_INFINITE)
|
Fix incorrect pruning in qsearch
Only do countermove based pruning in qsearch if we already have a move with a better score than a TB loss.
This patch fixes a bug (started as 843a961) that incorrectly prunes moves if in check,
and adds an assert to make sure no wrong mate scores are given in the future.
It replaces a no-op moveCount check with a check for bestValue.
Initially discussed in #3171 and later in #3199, #3198 and #3210.
This PR effectively closes #3171
It also likely fixes #3196 where this causes user visible incorrect TB scores,
which probably result from these incorrect mate scores.
Passed STC and LTC non-regression tests.
https://tests.stockfishchess.org/tests/view/5f9ef8dabca9bf35bae7f648
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 21672 W: 2339 L: 2230 D: 17103
Ptnml(0-2): 126, 1689, 7083, 1826, 112
https://tests.stockfishchess.org/tests/view/5f9f0caebca9bf35bae7f666
LLR: 2.97 (-2.94,2.94) {-0.75,0.25}
Total: 33152 W: 1551 L: 1485 D: 30116
Ptnml(0-2): 27, 1308, 13832, 1390, 19
closes https://github.com/official-stockfish/Stockfish/pull/3214
Bench: 3625915
2020-11-01 10:33:17 -07:00
|
|
|
{
|
|
|
|
assert(!MoveList<LEGAL>(pos).size());
|
|
|
|
|
2011-12-28 05:22:09 -07:00
|
|
|
return mated_in(ss->ply); // Plies to mate from the root
|
Fix incorrect pruning in qsearch
Only do countermove based pruning in qsearch if we already have a move with a better score than a TB loss.
This patch fixes a bug (started as 843a961) that incorrectly prunes moves if in check,
and adds an assert to make sure no wrong mate scores are given in the future.
It replaces a no-op moveCount check with a check for bestValue.
Initially discussed in #3171 and later in #3199, #3198 and #3210.
This PR effectively closes #3171
It also likely fixes #3196 where this causes user visible incorrect TB scores,
which probably result from these incorrect mate scores.
Passed STC and LTC non-regression tests.
https://tests.stockfishchess.org/tests/view/5f9ef8dabca9bf35bae7f648
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 21672 W: 2339 L: 2230 D: 17103
Ptnml(0-2): 126, 1689, 7083, 1826, 112
https://tests.stockfishchess.org/tests/view/5f9f0caebca9bf35bae7f666
LLR: 2.97 (-2.94,2.94) {-0.75,0.25}
Total: 33152 W: 1551 L: 1485 D: 30116
Ptnml(0-2): 27, 1308, 13832, 1390, 19
closes https://github.com/official-stockfish/Stockfish/pull/3214
Bench: 3625915
2020-11-01 10:33:17 -07:00
|
|
|
}
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// Save gathered info in transposition table
|
2019-01-09 07:05:28 -07:00
|
|
|
tte->save(posKey, value_to_tt(bestValue, ss->ply), pvHit,
|
2018-11-25 03:27:40 -07:00
|
|
|
bestValue >= beta ? BOUND_LOWER :
|
|
|
|
PvNode && bestValue > oldAlpha ? BOUND_EXACT : BOUND_UPPER,
|
2018-07-03 16:58:16 -06:00
|
|
|
ttDepth, bestMove, ss->staticEval);
|
2009-09-18 02:32:57 -06:00
|
|
|
|
2010-01-08 03:45:46 -07:00
|
|
|
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
|
2009-04-18 07:03:33 -06:00
|
|
|
|
2008-08-31 23:59:13 -06:00
|
|
|
return bestValue;
|
|
|
|
}
|
|
|
|
|
2010-12-14 06:49:06 -07:00
|
|
|
|
Fix for incorrect VALUE_MATE_IN_MAX_PLY usage.
Fixes #2533, fixes #2543, fixes #2423.
the code that prevents false mate announcements depending on the TT
state (GHI), incorrectly used VALUE_MATE_IN_MAX_PLY. The latter
constant, however, also includes, counterintuitively, the TB win range.
This patch fixes that, by restoring the behavior for TB win scores,
while retaining the false mate correctness, and improving the mate
finding ability. In particular
no alse mates are announced with the poisened hash testcase
```
position fen 8/8/8/3k4/8/8/6K1/7R w - - 0 1
go depth 40
position fen 8/8/8/3k4/8/8/6K1/7R w - - 76 1
go depth 20
ucinewgame
```
mates are found with the testcases reported in #2543
```
position fen 4k3/3pp3/8/8/8/8/2PPP3/4K3 w - - 0 1
setoption name Hash value 1024
go depth 55
ucinewgame
```
and
```
position fen 4k3/4p3/8/8/8/8/3PP3/4K3 w - - 0 1
setoption name Hash value 1024
go depth 45
ucinewgame
```
furthermore, on the mate finding benchmark (ChestUCI_23102018.epd),
performance improves over master, roughly reaching performance with the
false mate protection reverted
```
Analyzing 6566 mate positions for best and found mates:
----------------best ---------------found
nodes master revert fixed master revert fixed
16000000 4233 4236 4235 5200 5201 5199
32000000 4583 4585 4585 5417 5424 5418
64000000 4852 4853 4855 5575 5584 5579
128000000 5071 5068 5066 5710 5720 5716
256000000 5280 5282 5279 5819 5827 5826
512000000 5471 5468 5468 5919 5935 5932
```
On a testcase with TB enabled, progress is made consistently, contrary
to master
```
setoption name SyzygyPath value ../../../syzygy/3-4-5/
setoption name Hash value 2048
position fen 1R6/3k4/8/K2p4/4n3/2P5/8/8 w - - 0 1
go depth 58
ucinewgame
```
The PR (prior to a rewrite for clarity)
passed STC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 65405 W: 12454 L: 12384 D: 40567
Ptnml(0-2): 920, 7256, 16285, 7286, 944
http://tests.stockfishchess.org/tests/view/5e441a3be70d848499f63d15
passed LTC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 27096 W: 3477 L: 3413 D: 20206
Ptnml(0-2): 128, 2215, 8776, 2292, 122
http://tests.stockfishchess.org/tests/view/5e44e277e70d848499f63d63
The incorrectly named VALUE_MATE_IN_MAX_PLY and VALUE_MATED_IN_MAX_PLY
were renamed into VALUE_TB_WIN_IN_MAX_PLY and VALUE_TB_LOSS_IN_MAX_PLY,
and correclty defined VALUE_MATE_IN_MAX_PLY and VALUE_MATED_IN_MAX_PLY
were introduced.
One further (corner case) mistake using these constants was fixed (go
mate X), which could lead to a premature return if X > MAX_PLY / 2,
but TB were present.
Thanks to @svivanov72 for one of the reports and help fixing the issue.
closes https://github.com/official-stockfish/Stockfish/pull/2552
Bench: 4932981
2020-02-11 12:42:32 -07:00
|
|
|
// value_to_tt() adjusts a mate or TB score from "plies to mate from the root" to
|
2020-06-24 14:19:58 -06:00
|
|
|
// "plies to mate from the current position". Standard scores are unchanged.
|
2013-12-02 11:04:09 -07:00
|
|
|
// The function is called before storing a value in the transposition table.
|
2012-10-27 06:25:31 -06:00
|
|
|
|
|
|
|
Value value_to_tt(Value v, int ply) {
|
|
|
|
|
|
|
|
assert(v != VALUE_NONE);
|
|
|
|
|
Fix for incorrect VALUE_MATE_IN_MAX_PLY usage.
Fixes #2533, fixes #2543, fixes #2423.
the code that prevents false mate announcements depending on the TT
state (GHI), incorrectly used VALUE_MATE_IN_MAX_PLY. The latter
constant, however, also includes, counterintuitively, the TB win range.
This patch fixes that, by restoring the behavior for TB win scores,
while retaining the false mate correctness, and improving the mate
finding ability. In particular
no alse mates are announced with the poisened hash testcase
```
position fen 8/8/8/3k4/8/8/6K1/7R w - - 0 1
go depth 40
position fen 8/8/8/3k4/8/8/6K1/7R w - - 76 1
go depth 20
ucinewgame
```
mates are found with the testcases reported in #2543
```
position fen 4k3/3pp3/8/8/8/8/2PPP3/4K3 w - - 0 1
setoption name Hash value 1024
go depth 55
ucinewgame
```
and
```
position fen 4k3/4p3/8/8/8/8/3PP3/4K3 w - - 0 1
setoption name Hash value 1024
go depth 45
ucinewgame
```
furthermore, on the mate finding benchmark (ChestUCI_23102018.epd),
performance improves over master, roughly reaching performance with the
false mate protection reverted
```
Analyzing 6566 mate positions for best and found mates:
----------------best ---------------found
nodes master revert fixed master revert fixed
16000000 4233 4236 4235 5200 5201 5199
32000000 4583 4585 4585 5417 5424 5418
64000000 4852 4853 4855 5575 5584 5579
128000000 5071 5068 5066 5710 5720 5716
256000000 5280 5282 5279 5819 5827 5826
512000000 5471 5468 5468 5919 5935 5932
```
On a testcase with TB enabled, progress is made consistently, contrary
to master
```
setoption name SyzygyPath value ../../../syzygy/3-4-5/
setoption name Hash value 2048
position fen 1R6/3k4/8/K2p4/4n3/2P5/8/8 w - - 0 1
go depth 58
ucinewgame
```
The PR (prior to a rewrite for clarity)
passed STC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 65405 W: 12454 L: 12384 D: 40567
Ptnml(0-2): 920, 7256, 16285, 7286, 944
http://tests.stockfishchess.org/tests/view/5e441a3be70d848499f63d15
passed LTC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 27096 W: 3477 L: 3413 D: 20206
Ptnml(0-2): 128, 2215, 8776, 2292, 122
http://tests.stockfishchess.org/tests/view/5e44e277e70d848499f63d63
The incorrectly named VALUE_MATE_IN_MAX_PLY and VALUE_MATED_IN_MAX_PLY
were renamed into VALUE_TB_WIN_IN_MAX_PLY and VALUE_TB_LOSS_IN_MAX_PLY,
and correclty defined VALUE_MATE_IN_MAX_PLY and VALUE_MATED_IN_MAX_PLY
were introduced.
One further (corner case) mistake using these constants was fixed (go
mate X), which could lead to a premature return if X > MAX_PLY / 2,
but TB were present.
Thanks to @svivanov72 for one of the reports and help fixing the issue.
closes https://github.com/official-stockfish/Stockfish/pull/2552
Bench: 4932981
2020-02-11 12:42:32 -07:00
|
|
|
return v >= VALUE_TB_WIN_IN_MAX_PLY ? v + ply
|
|
|
|
: v <= VALUE_TB_LOSS_IN_MAX_PLY ? v - ply : v;
|
2012-10-27 06:25:31 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
|
2020-06-24 14:19:58 -06:00
|
|
|
// value_from_tt() is the inverse of value_to_tt(): it adjusts a mate or TB score
|
|
|
|
// from the transposition table (which refers to the plies to mate/be mated from
|
|
|
|
// current position) to "plies to mate/be mated (TB win/loss) from the root". However,
|
|
|
|
// for mate scores, to avoid potentially false mate scores related to the 50 moves rule
|
|
|
|
// and the graph history interaction, we return an optimal TB score instead.
|
2012-10-27 06:25:31 -06:00
|
|
|
|
Fix incorrect mate score.
Current master 648c7ec25db2040c0af34dd846dfa3f57af5ad0a will generate an
incorrect mate score for:
```
setoption name Hash value 8
setoption name Threads value 1
position fen 8/1p2KP2/1p4q1/1Pp5/2P5/N1Pp1k2/3P4/1N6 b - - 76 40
go depth 49
```
even though the position is a draw. Generally, SF tries to display only
proven mate scores, so this is a bug.
This was posted http://www.talkchess.com/forum3/viewtopic.php?f=2&t=72166
by Uri Blass, with the correct analysis that this must be related to the
50 moves draw rule being ignored somewhere.
Indeed, this is possible as positions and there eval are stored in the TT,
without reference to the 50mr counter. Depending on the search path followed
a position can thus be mate or draw in the TT (GHI or Graph history interaction).
Therefore, to prove mate lines, the TT content has to be used with care. Rather
than ignoring TT content in general or for mate scores (which impact search or
mate finding), it is possible to be more selective. In particular, @WOnder93
suggested to only ignore the TT if the 50mr draw ply is closer than the mate
ply. This patch implements this idea, by clamping the eval in the TT to
+-VALUE_MATED_IN_MAX_PLY. This retains the TTmove, but causes a research of
these lines (with the current 50mr counter) as needed.
This patch hardly ever affects search (as indicated by the unchanged
bench), but fixes the testcase. As the conditions are very specific,
also mate finding will almost never be less efficient (testing welcome).
It was also shown to pass STC and LTC non-regression testing, in a form
using if/then/else instead of ternary operators:
STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 93605 W: 15346 L: 15340 D: 62919
http://tests.stockfishchess.org/tests/view/5db45bb00ebc5908127538d4
LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 33873 W: 7359 L: 7261 D: 19253
http://tests.stockfishchess.org/tests/view/5db4c8940ebc5902d6b146fc
closes https://github.com/official-stockfish/Stockfish/issues/2370
Bench: 4362323
2019-10-26 08:34:19 -06:00
|
|
|
Value value_from_tt(Value v, int ply, int r50c) {
|
2012-10-27 06:25:31 -06:00
|
|
|
|
Fix for incorrect VALUE_MATE_IN_MAX_PLY usage.
Fixes #2533, fixes #2543, fixes #2423.
the code that prevents false mate announcements depending on the TT
state (GHI), incorrectly used VALUE_MATE_IN_MAX_PLY. The latter
constant, however, also includes, counterintuitively, the TB win range.
This patch fixes that, by restoring the behavior for TB win scores,
while retaining the false mate correctness, and improving the mate
finding ability. In particular
no alse mates are announced with the poisened hash testcase
```
position fen 8/8/8/3k4/8/8/6K1/7R w - - 0 1
go depth 40
position fen 8/8/8/3k4/8/8/6K1/7R w - - 76 1
go depth 20
ucinewgame
```
mates are found with the testcases reported in #2543
```
position fen 4k3/3pp3/8/8/8/8/2PPP3/4K3 w - - 0 1
setoption name Hash value 1024
go depth 55
ucinewgame
```
and
```
position fen 4k3/4p3/8/8/8/8/3PP3/4K3 w - - 0 1
setoption name Hash value 1024
go depth 45
ucinewgame
```
furthermore, on the mate finding benchmark (ChestUCI_23102018.epd),
performance improves over master, roughly reaching performance with the
false mate protection reverted
```
Analyzing 6566 mate positions for best and found mates:
----------------best ---------------found
nodes master revert fixed master revert fixed
16000000 4233 4236 4235 5200 5201 5199
32000000 4583 4585 4585 5417 5424 5418
64000000 4852 4853 4855 5575 5584 5579
128000000 5071 5068 5066 5710 5720 5716
256000000 5280 5282 5279 5819 5827 5826
512000000 5471 5468 5468 5919 5935 5932
```
On a testcase with TB enabled, progress is made consistently, contrary
to master
```
setoption name SyzygyPath value ../../../syzygy/3-4-5/
setoption name Hash value 2048
position fen 1R6/3k4/8/K2p4/4n3/2P5/8/8 w - - 0 1
go depth 58
ucinewgame
```
The PR (prior to a rewrite for clarity)
passed STC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 65405 W: 12454 L: 12384 D: 40567
Ptnml(0-2): 920, 7256, 16285, 7286, 944
http://tests.stockfishchess.org/tests/view/5e441a3be70d848499f63d15
passed LTC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 27096 W: 3477 L: 3413 D: 20206
Ptnml(0-2): 128, 2215, 8776, 2292, 122
http://tests.stockfishchess.org/tests/view/5e44e277e70d848499f63d63
The incorrectly named VALUE_MATE_IN_MAX_PLY and VALUE_MATED_IN_MAX_PLY
were renamed into VALUE_TB_WIN_IN_MAX_PLY and VALUE_TB_LOSS_IN_MAX_PLY,
and correclty defined VALUE_MATE_IN_MAX_PLY and VALUE_MATED_IN_MAX_PLY
were introduced.
One further (corner case) mistake using these constants was fixed (go
mate X), which could lead to a premature return if X > MAX_PLY / 2,
but TB were present.
Thanks to @svivanov72 for one of the reports and help fixing the issue.
closes https://github.com/official-stockfish/Stockfish/pull/2552
Bench: 4932981
2020-02-11 12:42:32 -07:00
|
|
|
if (v == VALUE_NONE)
|
|
|
|
return VALUE_NONE;
|
|
|
|
|
|
|
|
if (v >= VALUE_TB_WIN_IN_MAX_PLY) // TB win or better
|
|
|
|
{
|
|
|
|
if (v >= VALUE_MATE_IN_MAX_PLY && VALUE_MATE - v > 99 - r50c)
|
|
|
|
return VALUE_MATE_IN_MAX_PLY - 1; // do not return a potentially false mate score
|
|
|
|
|
|
|
|
return v - ply;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (v <= VALUE_TB_LOSS_IN_MAX_PLY) // TB loss or worse
|
|
|
|
{
|
|
|
|
if (v <= VALUE_MATED_IN_MAX_PLY && VALUE_MATE + v > 99 - r50c)
|
|
|
|
return VALUE_MATED_IN_MAX_PLY + 1; // do not return a potentially false mate score
|
|
|
|
|
|
|
|
return v + ply;
|
|
|
|
}
|
|
|
|
|
|
|
|
return v;
|
2012-10-27 06:25:31 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
|
2014-11-21 01:10:52 -07:00
|
|
|
// update_pv() adds current move and appends child pv[]
|
2014-11-18 03:57:57 -07:00
|
|
|
|
2014-11-21 01:10:52 -07:00
|
|
|
void update_pv(Move* pv, Move move, Move* childPv) {
|
2014-11-18 03:57:57 -07:00
|
|
|
|
2014-11-21 01:10:52 -07:00
|
|
|
for (*pv++ = move; childPv && *childPv != MOVE_NONE; )
|
|
|
|
*pv++ = *childPv++;
|
2014-11-18 03:57:57 -07:00
|
|
|
*pv = MOVE_NONE;
|
|
|
|
}
|
|
|
|
|
2014-01-05 06:08:26 -07:00
|
|
|
|
Refactor final stats updates.
This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done.
Effectively, all stat updates that need to be done after search is finished and a bestmove is found,
are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```.
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```.
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture).
passed non-regression STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 75196 W: 16364 L: 16347 D: 42485
http://tests.stockfishchess.org/tests/view/5db004ec0ebc5902c06db9e1
The diff is most easily readable as ```git diff master --patience```
No functional change
2019-10-23 00:26:47 -06:00
|
|
|
// update_all_stats() updates stats at the end of search() when a bestMove is found
|
2014-01-05 06:08:26 -07:00
|
|
|
|
Refactor final stats updates.
This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done.
Effectively, all stat updates that need to be done after search is finished and a bestmove is found,
are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```.
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```.
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture).
passed non-regression STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 75196 W: 16364 L: 16347 D: 42485
http://tests.stockfishchess.org/tests/view/5db004ec0ebc5902c06db9e1
The diff is most easily readable as ```git diff master --patience```
No functional change
2019-10-23 00:26:47 -06:00
|
|
|
void update_all_stats(const Position& pos, Stack* ss, Move bestMove, Value bestValue, Value beta, Square prevSq,
|
Revert 5 recent patches
Revert 5 patches which were merged, but lead to a regression test that showed negative Elo gain:
http://tests.stockfishchess.org/tests/view/5e307251ab2d69d58394fdb9
This was discussed in depth in:
https://github.com/official-stockfish/Stockfish/issues/2531
Each patch was removed and tested as a simplification, full list below, and the whole combo as well.
After the revert the regression test showed a neutral result:
http://tests.stockfishchess.org/tests/view/5e334851708b13464ceea33c
As a result of this experience, the SPRT testing bounds will be made more strict.
Reverted patches:
1 Dynamic Complexity 6d0eabd5fe2961551477820ab7619e2c31e01ffd :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31fcacec661e2e6a340d08 :
LLR: 2.97 (-2.94,2.94) {-1.50,0.50}
Total: 38130 W: 7326 L: 7189 D: 23615
Ptnml(0-2): 677, 4346, 8843, 4545, 646
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c18fec661e2e6a340d73 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 38675 W: 4941 L: 4866 D: 28868
Ptnml(0-2): 270, 3556, 11429, 3584, 291
3 More bonus for bestMoves on past PV nodes 71e0b5385e2717679a57c6b77d8c7ac5fff3b89f :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31fe93ec661e2e6a340d10 :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 46100 W: 8853 L: 8727 D: 28520
Ptnml(0-2): 796, 5297, 10749, 5387, 813
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c187ec661e2e6a340d71 :
LLR: 2.96 (-2.94,2.94) {-1.50,0.50}
Total: 16920 W: 2161 L: 2055 D: 12704
Ptnml(0-2): 115, 1498, 5006, 1569, 130
4 Tweak Restricted Piece Bonus 0ae00454ba6928d181b46103e5c83e6d58fcebe5 :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31fefaec661e2e6a340d15 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 88328 W: 17060 L: 16997 D: 54271
Ptnml(0-2): 1536, 10446, 20169, 10422, 1581
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c17aec661e2e6a340d6f :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 34784 W: 4551 L: 4466 D: 25767
Ptnml(0-2): 255, 3279, 10061, 3345, 262
5 History update for pruned captures 01b6088af39902001d2d6844561b6a2faa549282 :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31ff5eec661e2e6a340d1a :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 29541 W: 5735 L: 5588 D: 18218
Ptnml(0-2): 483, 3445, 6820, 3469, 545
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c196ec661e2e6a340d75 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 22177 W: 2854 L: 2757 D: 16566
Ptnml(0-2): 143, 2005, 6555, 2055, 164
6 Tweak trapped rook penalty 18fc21eba0368fd5e3c4c4b8ee1000c9ac445425 :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31ffb1ec661e2e6a340d1c :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 24476 W: 4727 L: 4569 D: 15180
Ptnml(0-2): 390, 2834, 5659, 2933, 417
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c19eec661e2e6a340d77 :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 97332 W: 12492 L: 12466 D: 72374
Ptnml(0-2): 690, 9107, 28738, 9034, 720
All 5 as one simplification :
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e334098708b13464ceea330 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 7829 W: 1079 L: 964 D: 5786
Ptnml(0-2): 52, 690, 2281, 781, 65
Bench: 5153165
2020-01-30 13:44:04 -07:00
|
|
|
Move* quietsSearched, int quietCount, Move* capturesSearched, int captureCount, Depth depth) {
|
2016-08-23 07:57:56 -06:00
|
|
|
|
Refactor final stats updates.
This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done.
Effectively, all stat updates that need to be done after search is finished and a bestmove is found,
are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```.
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```.
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture).
passed non-regression STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 75196 W: 16364 L: 16347 D: 42485
http://tests.stockfishchess.org/tests/view/5db004ec0ebc5902c06db9e1
The diff is most easily readable as ```git diff master --patience```
No functional change
2019-10-23 00:26:47 -06:00
|
|
|
int bonus1, bonus2;
|
|
|
|
Color us = pos.side_to_move();
|
|
|
|
Thread* thisThread = pos.this_thread();
|
|
|
|
CapturePieceToHistory& captureHistory = thisThread->captureHistory;
|
|
|
|
Piece moved_piece = pos.moved_piece(bestMove);
|
|
|
|
PieceType captured = type_of(pos.piece_on(to_sq(bestMove)));
|
|
|
|
|
|
|
|
bonus1 = stat_bonus(depth + 1);
|
Search Parameters Tuning
A simple tuning on search.cpp.
based SPSA test:
https://tests.stockfishchess.org/tests/view/601f2a787f517a561bc493cd
passed STC:
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 117840 W: 10796 L: 10508 D: 96536
Ptnml(0-2): 422, 8381, 41041, 8639, 437
https://tests.stockfishchess.org/tests/view/602144c37f517a561bc494ae
passed LTC:
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 25024 W: 972 L: 847 D: 23205
Ptnml(0-2): 7, 767, 10847, 876, 15
https://tests.stockfishchess.org/tests/view/602156877f517a561bc494be
closes https://github.com/official-stockfish/Stockfish/pull/3340
Bench: 3974098
2021-02-04 17:50:22 -07:00
|
|
|
bonus2 = bestValue > beta + PawnValueMg ? bonus1 // larger bonus
|
|
|
|
: std::min(bonus1, stat_bonus(depth)); // smaller bonus
|
Refactor final stats updates.
This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done.
Effectively, all stat updates that need to be done after search is finished and a bestmove is found,
are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```.
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```.
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture).
passed non-regression STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 75196 W: 16364 L: 16347 D: 42485
http://tests.stockfishchess.org/tests/view/5db004ec0ebc5902c06db9e1
The diff is most easily readable as ```git diff master --patience```
No functional change
2019-10-23 00:26:47 -06:00
|
|
|
|
|
|
|
if (!pos.capture_or_promotion(bestMove))
|
|
|
|
{
|
2020-12-01 05:02:35 -07:00
|
|
|
// Increase stats for the best move in case it was a quiet move
|
Improve move order near the root
Current move histories are known to work well near the leaves, whilst at
higher depths they aren't very helpful. To address this problem this
patch introduces a table dedicated for what's happening at plies 0-3.
It's structured like mainHistory with ply index instead of color.
It get cleared with each new search and is filled during iterative
deepening at higher depths when recording successful quiet moves near
the root or traversing nodes which were in the principal variation
(ttPv).
Medium TC (20+0.2):
https://tests.stockfishchess.org/tests/view/5e4d358790a0a02810d096dc
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 100910 W: 16682 L: 16376 D: 67852
Ptnml(0-2): 1177, 10983, 25883, 11181, 1231
LTC:
https://tests.stockfishchess.org/tests/view/5e4e2cb790a0a02810d09714
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 80444 W: 10495 L: 10095 D: 59854
Ptnml(0-2): 551, 7479, 23803, 7797, 592
closes https://github.com/official-stockfish/Stockfish/pull/2557
Bench: 4705960
2020-02-21 06:01:59 -07:00
|
|
|
update_quiet_stats(pos, ss, bestMove, bonus2, depth);
|
Refactor final stats updates.
This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done.
Effectively, all stat updates that need to be done after search is finished and a bestmove is found,
are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```.
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```.
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture).
passed non-regression STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 75196 W: 16364 L: 16347 D: 42485
http://tests.stockfishchess.org/tests/view/5db004ec0ebc5902c06db9e1
The diff is most easily readable as ```git diff master --patience```
No functional change
2019-10-23 00:26:47 -06:00
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// Decrease stats for all non-best quiet moves
|
Refactor final stats updates.
This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done.
Effectively, all stat updates that need to be done after search is finished and a bestmove is found,
are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```.
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```.
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture).
passed non-regression STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 75196 W: 16364 L: 16347 D: 42485
http://tests.stockfishchess.org/tests/view/5db004ec0ebc5902c06db9e1
The diff is most easily readable as ```git diff master --patience```
No functional change
2019-10-23 00:26:47 -06:00
|
|
|
for (int i = 0; i < quietCount; ++i)
|
|
|
|
{
|
|
|
|
thisThread->mainHistory[us][from_to(quietsSearched[i])] << -bonus2;
|
|
|
|
update_continuation_histories(ss, pos.moved_piece(quietsSearched[i]), to_sq(quietsSearched[i]), -bonus2);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
else
|
2020-12-01 05:02:35 -07:00
|
|
|
// Increase stats for the best move in case it was a capture move
|
Refactor final stats updates.
This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done.
Effectively, all stat updates that need to be done after search is finished and a bestmove is found,
are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```.
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```.
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture).
passed non-regression STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 75196 W: 16364 L: 16347 D: 42485
http://tests.stockfishchess.org/tests/view/5db004ec0ebc5902c06db9e1
The diff is most easily readable as ```git diff master --patience```
No functional change
2019-10-23 00:26:47 -06:00
|
|
|
captureHistory[moved_piece][to_sq(bestMove)][captured] << bonus1;
|
2016-08-23 07:57:56 -06:00
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// Extra penalty for a quiet early move that was not a TT move or
|
|
|
|
// main killer move in previous ply when it gets refuted.
|
Adjust penalty on refuted early quiet moves
This patch changes how previous early moves are penalized in case
search finds a best move. Here, the first quiet move that was not
a transposition table move is penalized.
passed STC
https://tests.stockfishchess.org/tests/view/5f51d839ba100690c5cc5f69
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 10088 W: 1150 L: 997 D: 7941
Ptnml(0-2): 41, 772, 3278, 899, 54
passed LTC
https://tests.stockfishchess.org/tests/view/5f51e435ba100690c5cc5f76
LLR: 2.93 (-2.94,2.94) {0.25,1.25}
Total: 30808 W: 1564 L: 1405 D: 27839
Ptnml(0-2): 19, 1245, 12717, 1404, 19
closes https://github.com/official-stockfish/Stockfish/pull/3106
bench 3983758
2020-09-04 06:53:59 -06:00
|
|
|
if ( ((ss-1)->moveCount == 1 + (ss-1)->ttHit || ((ss-1)->currentMove == (ss-1)->killers[0]))
|
Refactor final stats updates.
This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done.
Effectively, all stat updates that need to be done after search is finished and a bestmove is found,
are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```.
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```.
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture).
passed non-regression STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 75196 W: 16364 L: 16347 D: 42485
http://tests.stockfishchess.org/tests/view/5db004ec0ebc5902c06db9e1
The diff is most easily readable as ```git diff master --patience```
No functional change
2019-10-23 00:26:47 -06:00
|
|
|
&& !pos.captured_piece())
|
|
|
|
update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -bonus1);
|
2016-08-24 08:52:05 -06:00
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// Decrease stats for all non-best capture moves
|
Refactor final stats updates.
This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done.
Effectively, all stat updates that need to be done after search is finished and a bestmove is found,
are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```.
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```.
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture).
passed non-regression STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 75196 W: 16364 L: 16347 D: 42485
http://tests.stockfishchess.org/tests/view/5db004ec0ebc5902c06db9e1
The diff is most easily readable as ```git diff master --patience```
No functional change
2019-10-23 00:26:47 -06:00
|
|
|
for (int i = 0; i < captureCount; ++i)
|
|
|
|
{
|
|
|
|
moved_piece = pos.moved_piece(capturesSearched[i]);
|
|
|
|
captured = type_of(pos.piece_on(to_sq(capturesSearched[i])));
|
|
|
|
captureHistory[moved_piece][to_sq(capturesSearched[i])][captured] << -bonus1;
|
|
|
|
}
|
|
|
|
}
|
2017-11-03 05:37:11 -06:00
|
|
|
|
|
|
|
|
Refactor final stats updates.
This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done.
Effectively, all stat updates that need to be done after search is finished and a bestmove is found,
are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```.
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```.
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture).
passed non-regression STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 75196 W: 16364 L: 16347 D: 42485
http://tests.stockfishchess.org/tests/view/5db004ec0ebc5902c06db9e1
The diff is most easily readable as ```git diff master --patience```
No functional change
2019-10-23 00:26:47 -06:00
|
|
|
// update_continuation_histories() updates histories of the move pairs formed
|
2020-03-01 01:31:17 -07:00
|
|
|
// by moves at ply -1, -2, -4, and -6 with current move.
|
2018-07-03 17:11:54 -06:00
|
|
|
|
Refactor final stats updates.
This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done.
Effectively, all stat updates that need to be done after search is finished and a bestmove is found,
are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```.
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```.
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture).
passed non-regression STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 75196 W: 16364 L: 16347 D: 42485
http://tests.stockfishchess.org/tests/view/5db004ec0ebc5902c06db9e1
The diff is most easily readable as ```git diff master --patience```
No functional change
2019-10-23 00:26:47 -06:00
|
|
|
void update_continuation_histories(Stack* ss, Piece pc, Square to, int bonus) {
|
2017-11-03 05:37:11 -06:00
|
|
|
|
Refactor final stats updates.
This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done.
Effectively, all stat updates that need to be done after search is finished and a bestmove is found,
are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```.
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```.
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture).
passed non-regression STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 75196 W: 16364 L: 16347 D: 42485
http://tests.stockfishchess.org/tests/view/5db004ec0ebc5902c06db9e1
The diff is most easily readable as ```git diff master --patience```
No functional change
2019-10-23 00:26:47 -06:00
|
|
|
for (int i : {1, 2, 4, 6})
|
continuation histories when in check
If in check, don't write to continuation histories ss-4, ss-6.
Adding inCheck to the stack was needed, and might be useful for
future patches.
Passed STC:
https://tests.stockfishchess.org/tests/view/5e9ee24acaaff5d60a50b812
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 61774 W: 11725 L: 11449 D: 38600
Ptnml(0-2): 971, 7211, 14322, 7337, 1046
Passed LTC:
https://tests.stockfishchess.org/tests/view/5e9eecb7caaff5d60a50b831
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 250822 W: 32067 L: 31179 D: 187576
Ptnml(0-2): 1745, 23126, 74824, 23928, 1788
closes https://github.com/official-stockfish/Stockfish/pull/2645
bench: 4808463
2020-04-21 12:55:41 -06:00
|
|
|
{
|
2020-12-01 05:02:35 -07:00
|
|
|
// Only update first 2 continuation histories if we are in check
|
continuation histories when in check
If in check, don't write to continuation histories ss-4, ss-6.
Adding inCheck to the stack was needed, and might be useful for
future patches.
Passed STC:
https://tests.stockfishchess.org/tests/view/5e9ee24acaaff5d60a50b812
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 61774 W: 11725 L: 11449 D: 38600
Ptnml(0-2): 971, 7211, 14322, 7337, 1046
Passed LTC:
https://tests.stockfishchess.org/tests/view/5e9eecb7caaff5d60a50b831
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 250822 W: 32067 L: 31179 D: 187576
Ptnml(0-2): 1745, 23126, 74824, 23928, 1788
closes https://github.com/official-stockfish/Stockfish/pull/2645
bench: 4808463
2020-04-21 12:55:41 -06:00
|
|
|
if (ss->inCheck && i > 2)
|
|
|
|
break;
|
Refactor final stats updates.
This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done.
Effectively, all stat updates that need to be done after search is finished and a bestmove is found,
are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```.
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```.
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture).
passed non-regression STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 75196 W: 16364 L: 16347 D: 42485
http://tests.stockfishchess.org/tests/view/5db004ec0ebc5902c06db9e1
The diff is most easily readable as ```git diff master --patience```
No functional change
2019-10-23 00:26:47 -06:00
|
|
|
if (is_ok((ss-i)->currentMove))
|
|
|
|
(*(ss-i)->continuationHistory)[pc][to] << bonus;
|
continuation histories when in check
If in check, don't write to continuation histories ss-4, ss-6.
Adding inCheck to the stack was needed, and might be useful for
future patches.
Passed STC:
https://tests.stockfishchess.org/tests/view/5e9ee24acaaff5d60a50b812
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 61774 W: 11725 L: 11449 D: 38600
Ptnml(0-2): 971, 7211, 14322, 7337, 1046
Passed LTC:
https://tests.stockfishchess.org/tests/view/5e9eecb7caaff5d60a50b831
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 250822 W: 32067 L: 31179 D: 187576
Ptnml(0-2): 1745, 23126, 74824, 23928, 1788
closes https://github.com/official-stockfish/Stockfish/pull/2645
bench: 4808463
2020-04-21 12:55:41 -06:00
|
|
|
}
|
2017-11-03 05:37:11 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
|
Refactor final stats updates.
This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done.
Effectively, all stat updates that need to be done after search is finished and a bestmove is found,
are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```.
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```.
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture).
passed non-regression STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 75196 W: 16364 L: 16347 D: 42485
http://tests.stockfishchess.org/tests/view/5db004ec0ebc5902c06db9e1
The diff is most easily readable as ```git diff master --patience```
No functional change
2019-10-23 00:26:47 -06:00
|
|
|
// update_quiet_stats() updates move sorting heuristics
|
2016-08-24 08:52:05 -06:00
|
|
|
|
Improve move order near the root
Current move histories are known to work well near the leaves, whilst at
higher depths they aren't very helpful. To address this problem this
patch introduces a table dedicated for what's happening at plies 0-3.
It's structured like mainHistory with ply index instead of color.
It get cleared with each new search and is filled during iterative
deepening at higher depths when recording successful quiet moves near
the root or traversing nodes which were in the principal variation
(ttPv).
Medium TC (20+0.2):
https://tests.stockfishchess.org/tests/view/5e4d358790a0a02810d096dc
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 100910 W: 16682 L: 16376 D: 67852
Ptnml(0-2): 1177, 10983, 25883, 11181, 1231
LTC:
https://tests.stockfishchess.org/tests/view/5e4e2cb790a0a02810d09714
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 80444 W: 10495 L: 10095 D: 59854
Ptnml(0-2): 551, 7479, 23803, 7797, 592
closes https://github.com/official-stockfish/Stockfish/pull/2557
Bench: 4705960
2020-02-21 06:01:59 -07:00
|
|
|
void update_quiet_stats(const Position& pos, Stack* ss, Move move, int bonus, int depth) {
|
2016-08-23 07:57:56 -06:00
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// Update killers
|
2014-01-05 06:08:26 -07:00
|
|
|
if (ss->killers[0] != move)
|
|
|
|
{
|
|
|
|
ss->killers[1] = ss->killers[0];
|
|
|
|
ss->killers[0] = move;
|
|
|
|
}
|
2016-08-12 11:55:12 -06:00
|
|
|
|
2018-02-12 14:57:42 -07:00
|
|
|
Color us = pos.side_to_move();
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
Thread* thisThread = pos.this_thread();
|
2018-03-03 03:29:29 -07:00
|
|
|
thisThread->mainHistory[us][from_to(move)] << bonus;
|
2017-06-30 09:20:00 -06:00
|
|
|
update_continuation_histories(ss, pos.moved_piece(move), to_sq(move), bonus);
|
2015-01-31 02:43:47 -07:00
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// Penalty for reversed move in case of moved piece not being a pawn
|
2019-09-11 05:46:08 -06:00
|
|
|
if (type_of(pos.moved_piece(move)) != PAWN)
|
|
|
|
thisThread->mainHistory[us][from_to(reverse_move(move))] << -bonus;
|
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// Update countermove history
|
2017-03-08 19:35:23 -07:00
|
|
|
if (is_ok((ss-1)->currentMove))
|
2014-01-05 06:08:26 -07:00
|
|
|
{
|
2016-08-24 08:52:05 -06:00
|
|
|
Square prevSq = to_sq((ss-1)->currentMove);
|
2017-06-30 09:20:00 -06:00
|
|
|
thisThread->counterMoves[pos.piece_on(prevSq)][prevSq] = move;
|
2014-01-05 06:08:26 -07:00
|
|
|
}
|
Improve move order near the root
Current move histories are known to work well near the leaves, whilst at
higher depths they aren't very helpful. To address this problem this
patch introduces a table dedicated for what's happening at plies 0-3.
It's structured like mainHistory with ply index instead of color.
It get cleared with each new search and is filled during iterative
deepening at higher depths when recording successful quiet moves near
the root or traversing nodes which were in the principal variation
(ttPv).
Medium TC (20+0.2):
https://tests.stockfishchess.org/tests/view/5e4d358790a0a02810d096dc
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 100910 W: 16682 L: 16376 D: 67852
Ptnml(0-2): 1177, 10983, 25883, 11181, 1231
LTC:
https://tests.stockfishchess.org/tests/view/5e4e2cb790a0a02810d09714
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 80444 W: 10495 L: 10095 D: 59854
Ptnml(0-2): 551, 7479, 23803, 7797, 592
closes https://github.com/official-stockfish/Stockfish/pull/2557
Bench: 4705960
2020-02-21 06:01:59 -07:00
|
|
|
|
2020-12-01 05:02:35 -07:00
|
|
|
// Update low ply history
|
Retuned values after eval quantize patch.
The last search tune patch was tested before the implementation of #2733 which
presumably changed the search characteristics noticeably. Another tuning run was
done, see https://tests.stockfishchess.org/tests/view/5ee5b434ca6c451633a9a08c
and the updated values passed these tests:
STC:
LLR: 2.93 (-2.94,2.94) {-0.50,1.50}
Total: 34352 W: 6600 L: 6360 D: 21392
Ptnml(0-2): 581, 3947, 7914, 4119, 615
https://tests.stockfishchess.org/tests/view/5ee62f05ca6c451633a9a15f
LTC 60+0.6 th 1 :
LLR: 2.97 (-2.94,2.94) {0.25,1.75}
Total: 11176 W: 1499 L: 1304 D: 8373
Ptnml(0-2): 69, 933, 3403, 1100, 83
https://tests.stockfishchess.org/tests/view/5ee6205bca6c451633a9a147
SMP LTC 20+0.2 th 8 :
LLR: 2.93 (-2.94,2.94) {0.25,1.75}
Total: 54032 W: 6126 L: 5826 D: 42080
Ptnml(0-2): 278, 4454, 17280, 4698, 306
https://tests.stockfishchess.org/tests/view/5ee62f25ca6c451633a9a162
Closes https://github.com/official-stockfish/Stockfish/pull/2742
Bench 4957812
2020-06-14 14:50:27 -06:00
|
|
|
if (depth > 11 && ss->ply < MAX_LPH)
|
Assorted search parameter tune
STC https://tests.stockfishchess.org/tests/view/5f31219090816720665374ec
LLR: 2.96 (-2.94,2.94) {-0.50,1.50}
Total: 3376 W: 487 L: 359 D: 2530
Ptnml(0-2): 17, 253, 1042, 337, 39
LTC https://tests.stockfishchess.org/tests/view/5f3127f79081672066537502
LLR: 2.93 (-2.94,2.94) {0.25,1.75}
Total: 8360 W: 581 L: 475 D: 7304
Ptnml(0-2): 11, 407, 3238, 513, 11
closes https://github.com/official-stockfish/Stockfish/pull/2971
bench: 4733874
2020-08-10 07:38:44 -06:00
|
|
|
thisThread->lowPlyHistory[ss->ply][from_to(move)] << stat_bonus(depth - 7);
|
2014-01-05 06:08:26 -07:00
|
|
|
}
|
|
|
|
|
2015-01-25 03:07:43 -07:00
|
|
|
// When playing with strength handicap, choose best move among a set of RootMoves
|
|
|
|
// using a statistical rule dependent on 'level'. Idea by Heinz van Saanen.
|
2010-07-15 03:00:20 -06:00
|
|
|
|
2015-01-25 03:07:43 -07:00
|
|
|
Move Skill::pick_best(size_t multiPV) {
|
2010-07-15 03:00:20 -06:00
|
|
|
|
2016-04-11 08:45:36 -06:00
|
|
|
const RootMoves& rootMoves = Threads.main()->rootMoves;
|
2015-10-25 01:30:07 -06:00
|
|
|
static PRNG rng(now()); // PRNG sequence should be non-deterministic
|
2010-07-15 03:00:20 -06:00
|
|
|
|
2012-07-15 01:14:25 -06:00
|
|
|
// RootMoves are already sorted by score in descending order
|
2015-10-25 01:30:07 -06:00
|
|
|
Value topScore = rootMoves[0].score;
|
|
|
|
int delta = std::min(topScore - rootMoves[multiPV - 1].score, PawnValueMg);
|
2012-10-24 04:05:20 -06:00
|
|
|
int weakness = 120 - 2 * level;
|
2014-12-07 16:53:33 -07:00
|
|
|
int maxScore = -VALUE_INFINITE;
|
2012-07-15 01:14:25 -06:00
|
|
|
|
2015-10-25 01:30:07 -06:00
|
|
|
// Choose best move. For each move score we add two terms, both dependent on
|
2016-01-16 01:03:56 -07:00
|
|
|
// weakness. One is deterministic and bigger for weaker levels, and one is
|
2016-01-16 14:34:29 -07:00
|
|
|
// random. Then we choose the move with the resulting highest score.
|
2015-01-25 03:07:43 -07:00
|
|
|
for (size_t i = 0; i < multiPV; ++i)
|
2012-07-15 01:14:25 -06:00
|
|
|
{
|
|
|
|
// This is our magic formula
|
2015-10-25 01:30:07 -06:00
|
|
|
int push = ( weakness * int(topScore - rootMoves[i].score)
|
|
|
|
+ delta * (rng.rand<unsigned>() % weakness)) / 128;
|
2012-07-15 01:14:25 -06:00
|
|
|
|
2017-10-10 23:49:58 -06:00
|
|
|
if (rootMoves[i].score + push >= maxScore)
|
2012-07-15 01:14:25 -06:00
|
|
|
{
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
maxScore = rootMoves[i].score + push;
|
|
|
|
best = rootMoves[i].pv[0];
|
2012-07-15 01:14:25 -06:00
|
|
|
}
|
|
|
|
}
|
2015-10-25 01:30:07 -06:00
|
|
|
|
2012-07-15 01:14:25 -06:00
|
|
|
return best;
|
2010-07-15 03:00:20 -06:00
|
|
|
}
|
|
|
|
|
2017-06-23 23:15:46 -06:00
|
|
|
} // namespace
|
Get rid of timer thread
Unfortunately std::condition_variable::wait_for()
is not accurate in general case and the timer thread
can wake up also after tens or even hundreds of
millisecs after time has elapsded. CPU load, process
priorities, number of concurrent threads, even from
other processes, will have effect upon it.
Even official documentation says: "This function may
block for longer than timeout_duration due to scheduling
or resource contention delays."
So retire timer and use a polling scheme based on a
local thread counter that counts search() calls and
a small trick to keep polling frequency constant,
independently from the number of threads.
Tested for no regression at very fast TC 2+0.05 th 7:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 32969 W: 6720 L: 6620 D: 19629
TC 2+0.05 th 1:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 7765 W: 1917 L: 1765 D: 4083
And at STC TC, both single thread
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 15587 W: 3036 L: 2905 D: 9646
And with 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 8149 W: 1367 L: 1227 D: 5555
bench: 8639247
2015-11-03 03:15:14 -07:00
|
|
|
|
2020-06-24 14:19:58 -06:00
|
|
|
|
2018-02-12 14:57:42 -07:00
|
|
|
/// MainThread::check_time() is used to print debug info and, more importantly,
|
|
|
|
/// to detect when we are out of available time and thus stop the search.
|
Get rid of timer thread
Unfortunately std::condition_variable::wait_for()
is not accurate in general case and the timer thread
can wake up also after tens or even hundreds of
millisecs after time has elapsded. CPU load, process
priorities, number of concurrent threads, even from
other processes, will have effect upon it.
Even official documentation says: "This function may
block for longer than timeout_duration due to scheduling
or resource contention delays."
So retire timer and use a polling scheme based on a
local thread counter that counts search() calls and
a small trick to keep polling frequency constant,
independently from the number of threads.
Tested for no regression at very fast TC 2+0.05 th 7:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 32969 W: 6720 L: 6620 D: 19629
TC 2+0.05 th 1:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 7765 W: 1917 L: 1765 D: 4083
And at STC TC, both single thread
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 15587 W: 3036 L: 2905 D: 9646
And with 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 8149 W: 1367 L: 1227 D: 5555
bench: 8639247
2015-11-03 03:15:14 -07:00
|
|
|
|
2018-02-12 14:57:42 -07:00
|
|
|
void MainThread::check_time() {
|
2017-06-23 23:15:46 -06:00
|
|
|
|
2018-02-12 14:57:42 -07:00
|
|
|
if (--callsCnt > 0)
|
|
|
|
return;
|
2017-06-23 23:15:46 -06:00
|
|
|
|
2018-02-12 14:57:42 -07:00
|
|
|
// When using nodes, ensure checking rate is not lower than 0.1% of nodes
|
2018-03-14 14:35:57 -06:00
|
|
|
callsCnt = Limits.nodes ? std::min(1024, int(Limits.nodes / 1024)) : 1024;
|
Get rid of timer thread
Unfortunately std::condition_variable::wait_for()
is not accurate in general case and the timer thread
can wake up also after tens or even hundreds of
millisecs after time has elapsded. CPU load, process
priorities, number of concurrent threads, even from
other processes, will have effect upon it.
Even official documentation says: "This function may
block for longer than timeout_duration due to scheduling
or resource contention delays."
So retire timer and use a polling scheme based on a
local thread counter that counts search() calls and
a small trick to keep polling frequency constant,
independently from the number of threads.
Tested for no regression at very fast TC 2+0.05 th 7:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 32969 W: 6720 L: 6620 D: 19629
TC 2+0.05 th 1:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 7765 W: 1917 L: 1765 D: 4083
And at STC TC, both single thread
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 15587 W: 3036 L: 2905 D: 9646
And with 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 8149 W: 1367 L: 1227 D: 5555
bench: 8639247
2015-11-03 03:15:14 -07:00
|
|
|
|
2018-02-12 14:57:42 -07:00
|
|
|
static TimePoint lastInfoTime = now();
|
Get rid of timer thread
Unfortunately std::condition_variable::wait_for()
is not accurate in general case and the timer thread
can wake up also after tens or even hundreds of
millisecs after time has elapsded. CPU load, process
priorities, number of concurrent threads, even from
other processes, will have effect upon it.
Even official documentation says: "This function may
block for longer than timeout_duration due to scheduling
or resource contention delays."
So retire timer and use a polling scheme based on a
local thread counter that counts search() calls and
a small trick to keep polling frequency constant,
independently from the number of threads.
Tested for no regression at very fast TC 2+0.05 th 7:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 32969 W: 6720 L: 6620 D: 19629
TC 2+0.05 th 1:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 7765 W: 1917 L: 1765 D: 4083
And at STC TC, both single thread
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 15587 W: 3036 L: 2905 D: 9646
And with 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 8149 W: 1367 L: 1227 D: 5555
bench: 8639247
2015-11-03 03:15:14 -07:00
|
|
|
|
2018-03-27 08:22:53 -06:00
|
|
|
TimePoint elapsed = Time.elapsed();
|
2018-02-12 14:57:42 -07:00
|
|
|
TimePoint tick = Limits.startTime + elapsed;
|
Get rid of timer thread
Unfortunately std::condition_variable::wait_for()
is not accurate in general case and the timer thread
can wake up also after tens or even hundreds of
millisecs after time has elapsded. CPU load, process
priorities, number of concurrent threads, even from
other processes, will have effect upon it.
Even official documentation says: "This function may
block for longer than timeout_duration due to scheduling
or resource contention delays."
So retire timer and use a polling scheme based on a
local thread counter that counts search() calls and
a small trick to keep polling frequency constant,
independently from the number of threads.
Tested for no regression at very fast TC 2+0.05 th 7:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 32969 W: 6720 L: 6620 D: 19629
TC 2+0.05 th 1:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 7765 W: 1917 L: 1765 D: 4083
And at STC TC, both single thread
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 15587 W: 3036 L: 2905 D: 9646
And with 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 8149 W: 1367 L: 1227 D: 5555
bench: 8639247
2015-11-03 03:15:14 -07:00
|
|
|
|
2018-02-12 14:57:42 -07:00
|
|
|
if (tick - lastInfoTime >= 1000)
|
|
|
|
{
|
|
|
|
lastInfoTime = tick;
|
|
|
|
dbg_print();
|
|
|
|
}
|
Get rid of timer thread
Unfortunately std::condition_variable::wait_for()
is not accurate in general case and the timer thread
can wake up also after tens or even hundreds of
millisecs after time has elapsded. CPU load, process
priorities, number of concurrent threads, even from
other processes, will have effect upon it.
Even official documentation says: "This function may
block for longer than timeout_duration due to scheduling
or resource contention delays."
So retire timer and use a polling scheme based on a
local thread counter that counts search() calls and
a small trick to keep polling frequency constant,
independently from the number of threads.
Tested for no regression at very fast TC 2+0.05 th 7:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 32969 W: 6720 L: 6620 D: 19629
TC 2+0.05 th 1:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 7765 W: 1917 L: 1765 D: 4083
And at STC TC, both single thread
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 15587 W: 3036 L: 2905 D: 9646
And with 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 8149 W: 1367 L: 1227 D: 5555
bench: 8639247
2015-11-03 03:15:14 -07:00
|
|
|
|
2018-02-12 14:57:42 -07:00
|
|
|
// We should not stop pondering until told so by the GUI
|
Simplify pondering time management (#1899)
stopOnPonderhit is used to stop search quickly on a ponderhit. It is set by mainThread as part of its time management. However, master employs it as a signal between mainThread and the UCI thread. This is not necessary, it is sufficient for the UCI thread to signal that pondering finished, and mainThread should do its usual time-keeping job, and in this case stop immediately.
This patch implements this, removing stopOnPonderHit as an atomic variable from the ThreadPool,
and moving it as a normal variable to mainThread, reducing its scope. In MainThread::check_time() the search is stopped immediately if ponder switches to false, and the variable stopOnPonderHit is set.
Furthermore, ponder has been moved to mainThread, as the variable is only used to exchange signals between the UCI thread and mainThread.
The version has been tested locally (as fishtest doesn't support ponder):
Score of ponderSimp vs master: 2616 - 2528 - 8630 [0.503] 13774
Elo difference: 2.22 +/- 3.54
which indicates no regression.
No functional change.
2019-01-20 11:14:24 -07:00
|
|
|
if (ponder)
|
2018-02-12 14:57:42 -07:00
|
|
|
return;
|
Get rid of timer thread
Unfortunately std::condition_variable::wait_for()
is not accurate in general case and the timer thread
can wake up also after tens or even hundreds of
millisecs after time has elapsded. CPU load, process
priorities, number of concurrent threads, even from
other processes, will have effect upon it.
Even official documentation says: "This function may
block for longer than timeout_duration due to scheduling
or resource contention delays."
So retire timer and use a polling scheme based on a
local thread counter that counts search() calls and
a small trick to keep polling frequency constant,
independently from the number of threads.
Tested for no regression at very fast TC 2+0.05 th 7:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 32969 W: 6720 L: 6620 D: 19629
TC 2+0.05 th 1:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 7765 W: 1917 L: 1765 D: 4083
And at STC TC, both single thread
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 15587 W: 3036 L: 2905 D: 9646
And with 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 8149 W: 1367 L: 1227 D: 5555
bench: 8639247
2015-11-03 03:15:14 -07:00
|
|
|
|
Simplify pondering time management (#1899)
stopOnPonderhit is used to stop search quickly on a ponderhit. It is set by mainThread as part of its time management. However, master employs it as a signal between mainThread and the UCI thread. This is not necessary, it is sufficient for the UCI thread to signal that pondering finished, and mainThread should do its usual time-keeping job, and in this case stop immediately.
This patch implements this, removing stopOnPonderHit as an atomic variable from the ThreadPool,
and moving it as a normal variable to mainThread, reducing its scope. In MainThread::check_time() the search is stopped immediately if ponder switches to false, and the variable stopOnPonderHit is set.
Furthermore, ponder has been moved to mainThread, as the variable is only used to exchange signals between the UCI thread and mainThread.
The version has been tested locally (as fishtest doesn't support ponder):
Score of ponderSimp vs master: 2616 - 2528 - 8630 [0.503] 13774
Elo difference: 2.22 +/- 3.54
which indicates no regression.
No functional change.
2019-01-20 11:14:24 -07:00
|
|
|
if ( (Limits.use_time_management() && (elapsed > Time.maximum() - 10 || stopOnPonderhit))
|
2018-02-12 14:57:42 -07:00
|
|
|
|| (Limits.movetime && elapsed >= Limits.movetime)
|
|
|
|
|| (Limits.nodes && Threads.nodes_searched() >= (uint64_t)Limits.nodes))
|
|
|
|
Threads.stop = true;
|
|
|
|
}
|
Get rid of timer thread
Unfortunately std::condition_variable::wait_for()
is not accurate in general case and the timer thread
can wake up also after tens or even hundreds of
millisecs after time has elapsded. CPU load, process
priorities, number of concurrent threads, even from
other processes, will have effect upon it.
Even official documentation says: "This function may
block for longer than timeout_duration due to scheduling
or resource contention delays."
So retire timer and use a polling scheme based on a
local thread counter that counts search() calls and
a small trick to keep polling frequency constant,
independently from the number of threads.
Tested for no regression at very fast TC 2+0.05 th 7:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 32969 W: 6720 L: 6620 D: 19629
TC 2+0.05 th 1:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 7765 W: 1917 L: 1765 D: 4083
And at STC TC, both single thread
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 15587 W: 3036 L: 2905 D: 9646
And with 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 8149 W: 1367 L: 1227 D: 5555
bench: 8639247
2015-11-03 03:15:14 -07:00
|
|
|
|
2011-01-01 06:13:15 -07:00
|
|
|
|
2015-01-31 03:54:25 -07:00
|
|
|
/// UCI::pv() formats PV information according to the UCI protocol. UCI requires
|
|
|
|
/// that all (if any) unsearched PV lines are sent using a previous search score.
|
2011-01-01 06:13:15 -07:00
|
|
|
|
2015-01-31 03:54:25 -07:00
|
|
|
string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) {
|
2011-06-22 00:03:28 -06:00
|
|
|
|
2015-01-31 03:54:25 -07:00
|
|
|
std::stringstream ss;
|
2018-03-27 08:22:53 -06:00
|
|
|
TimePoint elapsed = Time.elapsed() + 1;
|
2016-04-11 08:45:36 -06:00
|
|
|
const RootMoves& rootMoves = pos.this_thread()->rootMoves;
|
2018-06-02 09:41:37 -06:00
|
|
|
size_t pvIdx = pos.this_thread()->pvIdx;
|
2018-02-04 13:42:56 -07:00
|
|
|
size_t multiPV = std::min((size_t)Options["MultiPV"], rootMoves.size());
|
2016-10-20 13:16:09 -06:00
|
|
|
uint64_t nodesSearched = Threads.nodes_searched();
|
|
|
|
uint64_t tbHits = Threads.tb_hits() + (TB::RootInTB ? rootMoves.size() : 0);
|
2011-06-22 00:03:28 -06:00
|
|
|
|
2015-01-31 03:54:25 -07:00
|
|
|
for (size_t i = 0; i < multiPV; ++i)
|
|
|
|
{
|
2019-12-06 02:11:45 -07:00
|
|
|
bool updated = rootMoves[i].score != -VALUE_INFINITE;
|
2011-12-14 01:21:00 -07:00
|
|
|
|
2020-08-31 14:53:20 -06:00
|
|
|
if (depth == 1 && !updated && i > 0)
|
2015-01-31 03:54:25 -07:00
|
|
|
continue;
|
2011-12-14 01:21:00 -07:00
|
|
|
|
2020-08-31 14:53:20 -06:00
|
|
|
Depth d = updated ? depth : std::max(1, depth - 1);
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
Value v = updated ? rootMoves[i].score : rootMoves[i].previousScore;
|
2015-01-18 00:05:05 -07:00
|
|
|
|
2020-08-31 14:53:20 -06:00
|
|
|
if (v == -VALUE_INFINITE)
|
|
|
|
v = VALUE_ZERO;
|
|
|
|
|
Fix for incorrect VALUE_MATE_IN_MAX_PLY usage.
Fixes #2533, fixes #2543, fixes #2423.
the code that prevents false mate announcements depending on the TT
state (GHI), incorrectly used VALUE_MATE_IN_MAX_PLY. The latter
constant, however, also includes, counterintuitively, the TB win range.
This patch fixes that, by restoring the behavior for TB win scores,
while retaining the false mate correctness, and improving the mate
finding ability. In particular
no alse mates are announced with the poisened hash testcase
```
position fen 8/8/8/3k4/8/8/6K1/7R w - - 0 1
go depth 40
position fen 8/8/8/3k4/8/8/6K1/7R w - - 76 1
go depth 20
ucinewgame
```
mates are found with the testcases reported in #2543
```
position fen 4k3/3pp3/8/8/8/8/2PPP3/4K3 w - - 0 1
setoption name Hash value 1024
go depth 55
ucinewgame
```
and
```
position fen 4k3/4p3/8/8/8/8/3PP3/4K3 w - - 0 1
setoption name Hash value 1024
go depth 45
ucinewgame
```
furthermore, on the mate finding benchmark (ChestUCI_23102018.epd),
performance improves over master, roughly reaching performance with the
false mate protection reverted
```
Analyzing 6566 mate positions for best and found mates:
----------------best ---------------found
nodes master revert fixed master revert fixed
16000000 4233 4236 4235 5200 5201 5199
32000000 4583 4585 4585 5417 5424 5418
64000000 4852 4853 4855 5575 5584 5579
128000000 5071 5068 5066 5710 5720 5716
256000000 5280 5282 5279 5819 5827 5826
512000000 5471 5468 5468 5919 5935 5932
```
On a testcase with TB enabled, progress is made consistently, contrary
to master
```
setoption name SyzygyPath value ../../../syzygy/3-4-5/
setoption name Hash value 2048
position fen 1R6/3k4/8/K2p4/4n3/2P5/8/8 w - - 0 1
go depth 58
ucinewgame
```
The PR (prior to a rewrite for clarity)
passed STC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 65405 W: 12454 L: 12384 D: 40567
Ptnml(0-2): 920, 7256, 16285, 7286, 944
http://tests.stockfishchess.org/tests/view/5e441a3be70d848499f63d15
passed LTC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 27096 W: 3477 L: 3413 D: 20206
Ptnml(0-2): 128, 2215, 8776, 2292, 122
http://tests.stockfishchess.org/tests/view/5e44e277e70d848499f63d63
The incorrectly named VALUE_MATE_IN_MAX_PLY and VALUE_MATED_IN_MAX_PLY
were renamed into VALUE_TB_WIN_IN_MAX_PLY and VALUE_TB_LOSS_IN_MAX_PLY,
and correclty defined VALUE_MATE_IN_MAX_PLY and VALUE_MATED_IN_MAX_PLY
were introduced.
One further (corner case) mistake using these constants was fixed (go
mate X), which could lead to a premature return if X > MAX_PLY / 2,
but TB were present.
Thanks to @svivanov72 for one of the reports and help fixing the issue.
closes https://github.com/official-stockfish/Stockfish/pull/2552
Bench: 4932981
2020-02-11 12:42:32 -07:00
|
|
|
bool tb = TB::RootInTB && abs(v) < VALUE_MATE_IN_MAX_PLY;
|
2018-06-02 09:41:37 -06:00
|
|
|
v = tb ? rootMoves[i].tbScore : v;
|
2012-07-14 06:19:16 -06:00
|
|
|
|
2015-01-31 03:54:25 -07:00
|
|
|
if (ss.rdbuf()->in_avail()) // Not at first line
|
|
|
|
ss << "\n";
|
2015-01-03 02:51:38 -07:00
|
|
|
|
2015-01-31 03:54:25 -07:00
|
|
|
ss << "info"
|
2019-09-28 14:27:23 -06:00
|
|
|
<< " depth " << d
|
2017-07-13 17:30:03 -06:00
|
|
|
<< " seldepth " << rootMoves[i].selDepth
|
2015-01-31 03:54:25 -07:00
|
|
|
<< " multipv " << i + 1
|
|
|
|
<< " score " << UCI::value(v);
|
2015-01-03 02:51:38 -07:00
|
|
|
|
Provide WDL statistics
A number of engines, GUIs and tournaments start to report WDL estimates
along or instead of scores. This patch enables reporting of those stats
in a more or less standard way (http://www.talkchess.com/forum3/viewtopic.php?t=72140)
The model this reporting uses is based on data derived from a few million fishtest LTC games,
given a score and a game ply, a win rate is provided that matches rather closely,
especially in the intermediate range [0.05, 0.95] that data. Some data is shown at
https://github.com/glinscott/fishtest/wiki/UsefulData#win-loss-draw-statistics-of-ltc-games-on-fishtest
Making the conversion game ply dependent is important for a good fit, and is in line
with experience that a +1 score in the early midgame is more likely a win than in the late endgame.
Even when enabled, the printing of the info causes no significant overhead.
Passed STC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 197112 W: 37226 L: 37347 D: 122539
Ptnml(0-2): 2591, 21025, 51464, 20866, 2610
https://tests.stockfishchess.org/tests/view/5ef79ef4f993893290cc146b
closes https://github.com/official-stockfish/Stockfish/pull/2778
No functional change
2020-06-27 13:29:29 -06:00
|
|
|
if (Options["UCI_ShowWDL"])
|
|
|
|
ss << UCI::wdl(v, pos.game_ply());
|
|
|
|
|
2018-06-02 09:41:37 -06:00
|
|
|
if (!tb && i == pvIdx)
|
2015-01-31 03:54:25 -07:00
|
|
|
ss << (v >= beta ? " lowerbound" : v <= alpha ? " upperbound" : "");
|
2011-12-14 01:21:00 -07:00
|
|
|
|
2016-10-20 13:16:09 -06:00
|
|
|
ss << " nodes " << nodesSearched
|
|
|
|
<< " nps " << nodesSearched * 1000 / elapsed;
|
2015-01-25 00:57:51 -07:00
|
|
|
|
2015-01-31 05:04:15 -07:00
|
|
|
if (elapsed > 1000) // Earlier makes little sense
|
2015-01-31 05:22:06 -07:00
|
|
|
ss << " hashfull " << TT.hashfull();
|
2011-12-14 01:21:00 -07:00
|
|
|
|
2016-10-20 13:16:09 -06:00
|
|
|
ss << " tbhits " << tbHits
|
2015-01-31 03:54:25 -07:00
|
|
|
<< " time " << elapsed
|
|
|
|
<< " pv";
|
2012-07-14 06:19:16 -06:00
|
|
|
|
Lazy SMP
Start all threads searching on root position and
use only the shared TT table as synching scheme.
It seems this scheme scales better than YBWC for
high number of threads.
Verified for nor regression at STC 3 threads
LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
Total: 40232 W: 6908 L: 7130 D: 26194
Verified for nor regression at LTC 3 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28186 W: 3908 L: 3798 D: 20480
Verified for nor regression at STC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 3607 W: 674 L: 526 D: 2407
Verified for nor regression at LTC 7 threads
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 4235 W: 671 L: 528 D: 3036
Tested with fixed games at LTC with 20 threads
ELO: 44.75 +-7.6 (95%) LOS: 100.0%
Total: 2069 W: 407 L: 142 D: 1520
Tested with fixed games at XLTC (120secs) with 20 threads
ELO: 28.01 +-6.7 (95%) LOS: 100.0%
Total: 2275 W: 349 L: 166 D: 1760
Original patch of mbootsector, with additional work
from Ivan Ivec (log formula), Joerg Oster (id loop
simplification) and Marco Costalba (assorted formatting
and rework).
Bench: 8116244
2015-10-06 00:15:17 -06:00
|
|
|
for (Move m : rootMoves[i].pv)
|
2015-01-31 03:54:25 -07:00
|
|
|
ss << " " << UCI::move(m, pos.is_chess960());
|
2011-06-22 00:03:28 -06:00
|
|
|
}
|
|
|
|
|
2015-01-31 03:54:25 -07:00
|
|
|
return ss.str();
|
|
|
|
}
|
2008-08-31 23:59:13 -06:00
|
|
|
|
2010-12-29 03:00:32 -07:00
|
|
|
|
2015-10-25 01:30:07 -06:00
|
|
|
/// RootMove::extract_ponder_from_tt() is called in case we have no ponder move
|
2016-01-16 14:34:29 -07:00
|
|
|
/// before exiting the search, for instance, in case we stop the search during a
|
2015-10-25 01:30:07 -06:00
|
|
|
/// fail high at root. We try hard to have a ponder move to return to the GUI,
|
|
|
|
/// otherwise in case of 'ponder on' we have nothing to think on.
|
2015-01-20 01:13:30 -07:00
|
|
|
|
2016-09-23 11:28:34 -06:00
|
|
|
bool RootMove::extract_ponder_from_tt(Position& pos) {
|
|
|
|
|
2015-01-20 01:13:30 -07:00
|
|
|
StateInfo st;
|
2021-04-19 11:50:19 -06:00
|
|
|
ASSERT_ALIGNED(&st, Eval::NNUE::CacheLineSize);
|
2020-11-03 03:23:35 -07:00
|
|
|
|
2015-01-31 04:31:00 -07:00
|
|
|
bool ttHit;
|
2015-01-20 01:13:30 -07:00
|
|
|
|
|
|
|
assert(pv.size() == 1);
|
|
|
|
|
2019-01-01 06:10:26 -07:00
|
|
|
if (pv[0] == MOVE_NONE)
|
2016-09-23 23:30:37 -06:00
|
|
|
return false;
|
|
|
|
|
2016-11-11 06:02:28 -07:00
|
|
|
pos.do_move(pv[0], st);
|
2015-01-31 04:31:00 -07:00
|
|
|
TTEntry* tte = TT.probe(pos.key(), ttHit);
|
|
|
|
|
|
|
|
if (ttHit)
|
|
|
|
{
|
|
|
|
Move m = tte->move(); // Local copy to be SMP safe
|
|
|
|
if (MoveList<LEGAL>(pos).contains(m))
|
2016-07-09 13:01:42 -06:00
|
|
|
pv.push_back(m);
|
2015-01-31 04:31:00 -07:00
|
|
|
}
|
|
|
|
|
2016-07-09 13:01:42 -06:00
|
|
|
pos.undo_move(pv[0]);
|
|
|
|
return pv.size() > 1;
|
2015-01-20 01:13:30 -07:00
|
|
|
}
|
2016-06-03 23:53:29 -06:00
|
|
|
|
2018-04-18 10:38:38 -06:00
|
|
|
void Tablebases::rank_root_moves(Position& pos, Search::RootMoves& rootMoves) {
|
2016-06-03 23:53:29 -06:00
|
|
|
|
|
|
|
RootInTB = false;
|
2018-04-18 20:16:19 -06:00
|
|
|
UseRule50 = bool(Options["Syzygy50MoveRule"]);
|
2019-09-28 14:27:23 -06:00
|
|
|
ProbeDepth = int(Options["SyzygyProbeDepth"]);
|
2018-04-18 20:16:19 -06:00
|
|
|
Cardinality = int(Options["SyzygyProbeLimit"]);
|
2018-04-18 10:38:38 -06:00
|
|
|
bool dtz_available = true;
|
2016-06-03 23:53:29 -06:00
|
|
|
|
2018-04-18 10:38:38 -06:00
|
|
|
// Tables with fewer pieces than SyzygyProbeLimit are searched with
|
|
|
|
// ProbeDepth == DEPTH_ZERO
|
2016-06-03 23:53:29 -06:00
|
|
|
if (Cardinality > MaxCardinality)
|
|
|
|
{
|
|
|
|
Cardinality = MaxCardinality;
|
2019-09-28 14:27:23 -06:00
|
|
|
ProbeDepth = 0;
|
2016-06-03 23:53:29 -06:00
|
|
|
}
|
|
|
|
|
2018-04-18 10:38:38 -06:00
|
|
|
if (Cardinality >= popcount(pos.pieces()) && !pos.can_castle(ANY_CASTLING))
|
|
|
|
{
|
|
|
|
// Rank moves using DTZ tables
|
|
|
|
RootInTB = root_probe(pos, rootMoves);
|
2017-11-07 01:26:13 -07:00
|
|
|
|
2018-04-18 10:38:38 -06:00
|
|
|
if (!RootInTB)
|
|
|
|
{
|
|
|
|
// DTZ tables are missing; try to rank moves using WDL tables
|
|
|
|
dtz_available = false;
|
|
|
|
RootInTB = root_probe_wdl(pos, rootMoves);
|
|
|
|
}
|
|
|
|
}
|
2016-06-03 23:53:29 -06:00
|
|
|
|
|
|
|
if (RootInTB)
|
|
|
|
{
|
2018-04-18 10:38:38 -06:00
|
|
|
// Sort moves according to TB rank
|
2020-08-30 19:40:49 -06:00
|
|
|
std::stable_sort(rootMoves.begin(), rootMoves.end(),
|
2018-06-02 09:41:37 -06:00
|
|
|
[](const RootMove &a, const RootMove &b) { return a.tbRank > b.tbRank; } );
|
2016-06-03 23:53:29 -06:00
|
|
|
|
2018-04-18 10:38:38 -06:00
|
|
|
// Probe during search only if DTZ is not available and we are winning
|
2018-06-02 09:41:37 -06:00
|
|
|
if (dtz_available || rootMoves[0].tbScore <= VALUE_DRAW)
|
2016-06-03 23:53:29 -06:00
|
|
|
Cardinality = 0;
|
|
|
|
}
|
2019-06-18 15:27:34 -06:00
|
|
|
else
|
|
|
|
{
|
|
|
|
// Clean up if root_probe() and root_probe_wdl() have failed
|
|
|
|
for (auto& m : rootMoves)
|
|
|
|
m.tbRank = 0;
|
|
|
|
}
|
2016-06-03 23:53:29 -06:00
|
|
|
}
|
2021-02-26 02:02:13 -07:00
|
|
|
|
|
|
|
} // namespace Stockfish
|