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Retire asymmThreshold

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Verified with 40K games at long TC does not regress:
ELO: 1.74 +-1.9 (95%) LOS: 96.2%
Total: 39624 W: 6402 L: 6203 D: 27019

bench: 7762310
This commit is contained in:
Marco Costalba 2013-12-28 10:30:35 +01:00
parent 59a9bc9351
commit f7742669cb
3 changed files with 3 additions and 15 deletions
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11
src/position.cpp
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@ -1029,7 +1029,7 @@ int Position::see_sign(Move m) const {
return see(m); return see(m);
} }
int Position::see(Move m, int asymmThreshold) const { int Position::see(Move m) const {
Square from, to; Square from, to;
Bitboard occupied, attackers, stmAttackers; Bitboard occupied, attackers, stmAttackers;
@ -1096,15 +1096,6 @@ int Position::see(Move m, int asymmThreshold) const {
} while (stmAttackers); } while (stmAttackers);
// If we are doing asymmetric SEE evaluation and the same side does the first
// and the last capture, it loses a tempo and gain must be at least worth
// 'asymmThreshold', otherwise we replace the score with a very low value,
// before negamaxing.
if (asymmThreshold)
for (int i = 0; i < slIndex; i += 2)
if (swapList[i] < asymmThreshold)
swapList[i] = - QueenValueMg * 16;
// Having built the swap list, we negamax through it to find the best // Having built the swap list, we negamax through it to find the best
// achievable score from the point of view of the side to move. // achievable score from the point of view of the side to move.
while (--slIndex) while (--slIndex)

2
src/position.h
View file

@ -141,7 +141,7 @@ public:
void undo_null_move(); void undo_null_move();
// Static exchange evaluation // Static exchange evaluation
int see(Move m, int asymmThreshold = 0) const; int see(Move m) const;
int see_sign(Move m) const; int see_sign(Move m) const;
// Accessing hash keys // Accessing hash keys

5
src/search.cpp
View file

@ -1220,10 +1220,7 @@ moves_loop: // When in check and at SpNode search starts from here
continue; continue;
} }
// Prune moves with negative or equal SEE and also moves with positive if (futilityBase < beta && pos.see(move) <= 0)
// SEE where capturing piece loses a tempo and SEE < beta - futilityBase.
if ( futilityBase < beta
&& pos.see(move, beta - futilityBase) <= 0)
{ {
bestValue = std::max(bestValue, futilityBase); bestValue = std::max(bestValue, futilityBase);
continue; continue;