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simplify logic for history based pruning 

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 34255 W: 6292 L: 6194 D: 21769

LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 89914 W: 11769 L: 11739 D: 66406

Bench: 6581936

Closes #1066
pull/1048/merge
Joost VandeVondele 2017-04-20 11:22:24 -07:00 committed by Joona Kiiski
parent 2d96e8fbe9
commit ced29248c9
2 changed files with 8 additions and 7 deletions
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1
src/movepick.h
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@ -66,6 +66,7 @@ struct Stats {
const T* operator[](Piece pc) const { return table[pc]; }
T* operator[](Piece pc) { return table[pc]; }
void clear() { std::memset(table, 0, sizeof(table)); }
void fill(const Value& v) { std::fill(&table[0][0], &table[PIECE_NB-1][SQUARE_NB-1]+1, v); };
void update(Piece pc, Square to, Move m) { table[pc][to] = m; }
void update(Piece pc, Square to, Value v) {

14
src/search.cpp
View File

@ -75,6 +75,9 @@ namespace {
int FutilityMoveCounts[2][16]; // [improving][depth]
int Reductions[2][2][64][64]; // [pv][improving][depth][moveNumber]
// Threshold used for countermoves based pruning.
const int CounterMovePruneThreshold = VALUE_ZERO;
template <bool PvNode> Depth reduction(bool i, Depth d, int mn) {
return Reductions[PvNode][i][std::min(d / ONE_PLY, 63)][std::min(mn, 63)] * ONE_PLY;
}
@ -192,6 +195,7 @@ void Search::clear() {
th->counterMoves.clear();
th->history.clear();
th->counterMoveHistory.clear();
th->counterMoveHistory[NO_PIECE][0].fill(Value(CounterMovePruneThreshold-1));
th->resetCalls = true;
}
@ -812,9 +816,6 @@ moves_loop: // When in check search starts from here
const CounterMoveStats& cmh = *(ss-1)->counterMoves;
const CounterMoveStats& fmh = *(ss-2)->counterMoves;
const CounterMoveStats& fm2 = *(ss-4)->counterMoves;
const bool cm_ok = is_ok((ss-1)->currentMove);
const bool fm_ok = is_ok((ss-2)->currentMove);
const bool f2_ok = is_ok((ss-4)->currentMove);
MovePicker mp(pos, ttMove, depth, ss);
value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
@ -916,9 +917,8 @@ moves_loop: // When in check search starts from here
// Countermoves based pruning
if ( lmrDepth < 3
&& ((cmh[moved_piece][to_sq(move)] < VALUE_ZERO) || !cm_ok)
&& ((fmh[moved_piece][to_sq(move)] < VALUE_ZERO) || !fm_ok)
&& ((fm2[moved_piece][to_sq(move)] < VALUE_ZERO) || !f2_ok || (cm_ok && fm_ok)))
&& (cmh[moved_piece][to_sq(move)] < CounterMovePruneThreshold)
&& (fmh[moved_piece][to_sq(move)] < CounterMovePruneThreshold))
continue;
// Futility pruning: parent node
@ -1123,7 +1123,7 @@ moves_loop: // When in check search starts from here
// Bonus for prior countermove that caused the fail low
else if ( depth >= 3 * ONE_PLY
&& !pos.captured_piece()
&& cm_ok)
&& is_ok((ss-1)->currentMove))
update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth));
if(!excludedMove)