106 lines
3.8 KiB
C++
106 lines
3.8 KiB
C++
/*
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Stockfish, a UCI chess playing engine derived from Glaurung 2.1
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Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file)
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Stockfish is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Stockfish is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <algorithm>
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#include <cfloat>
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#include <cmath>
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#include "search.h"
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#include "timeman.h"
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#include "uci.h"
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namespace Stockfish {
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TimeManagement Time; // Our global time management object
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/// TimeManagement::init() is called at the beginning of the search and calculates
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/// the bounds of time allowed for the current game ply. We currently support:
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// 1) x basetime (+ z increment)
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// 2) x moves in y seconds (+ z increment)
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void TimeManagement::init(Search::LimitsType& limits, Color us, int ply) {
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TimePoint moveOverhead = TimePoint(Options["Move Overhead"]);
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TimePoint slowMover = TimePoint(Options["Slow Mover"]);
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TimePoint npmsec = TimePoint(Options["nodestime"]);
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// optScale is a percentage of available time to use for the current move.
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// maxScale is a multiplier applied to optimumTime.
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double optScale, maxScale;
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// If we have to play in 'nodes as time' mode, then convert from time
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// to nodes, and use resulting values in time management formulas.
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// WARNING: to avoid time losses, the given npmsec (nodes per millisecond)
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// must be much lower than the real engine speed.
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if (npmsec)
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{
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if (!availableNodes) // Only once at game start
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availableNodes = npmsec * limits.time[us]; // Time is in msec
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// Convert from milliseconds to nodes
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limits.time[us] = TimePoint(availableNodes);
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limits.inc[us] *= npmsec;
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limits.npmsec = npmsec;
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}
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startTime = limits.startTime;
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// Maximum move horizon of 50 moves
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int mtg = limits.movestogo ? std::min(limits.movestogo, 50) : 50;
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// Make sure timeLeft is > 0 since we may use it as a divisor
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TimePoint timeLeft = std::max(TimePoint(1),
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limits.time[us] + limits.inc[us] * (mtg - 1) - moveOverhead * (2 + mtg));
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// Use extra time with larger increments
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double optExtra = std::clamp(1.0 + 12.0 * limits.inc[us] / limits.time[us], 1.0, 1.12);
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// A user may scale time usage by setting UCI option "Slow Mover"
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// Default is 100 and changing this value will probably lose elo.
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timeLeft = slowMover * timeLeft / 100;
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// x basetime (+ z increment)
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// If there is a healthy increment, timeLeft can exceed actual available
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// game time for the current move, so also cap to 20% of available game time.
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if (limits.movestogo == 0)
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{
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optScale = std::min(0.0084 + std::pow(ply + 3.0, 0.5) * 0.0042,
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0.2 * limits.time[us] / double(timeLeft))
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* optExtra;
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maxScale = std::min(7.0, 4.0 + ply / 12.0);
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}
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// x moves in y seconds (+ z increment)
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else
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{
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optScale = std::min((0.88 + ply / 116.4) / mtg,
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0.88 * limits.time[us] / double(timeLeft));
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maxScale = std::min(6.3, 1.5 + 0.11 * mtg);
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}
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// Never use more than 80% of the available time for this move
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optimumTime = TimePoint(optScale * timeLeft);
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maximumTime = TimePoint(std::min(0.8 * limits.time[us] - moveOverhead, maxScale * optimumTime));
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if (Options["Ponder"])
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optimumTime += optimumTime / 4;
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}
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} // namespace Stockfish
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