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More aggressive post-futility pruning

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This commit is contained in:
Joona Kiiski
2013-04-21 14:53:27 +01:00
parent f84f04742a
commit 8df17204f4
2 changed files with 7 additions and 2 deletions
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8
src/search.cpp
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@@ -643,10 +643,10 @@ namespace {
&& !ss->skipNullMove && !ss->skipNullMove
&& depth < 4 * ONE_PLY && depth < 4 * ONE_PLY
&& !inCheck && !inCheck
&& eval - FutilityMargins[depth][0] >= beta && eval - FutilityMargins[depth][(ss-1)->futMc] >= beta
&& abs(beta) < VALUE_MATE_IN_MAX_PLY && abs(beta) < VALUE_MATE_IN_MAX_PLY
&& pos.non_pawn_material(pos.side_to_move())) && pos.non_pawn_material(pos.side_to_move()))
return eval - FutilityMargins[depth][0]; return eval - FutilityMargins[depth][(ss-1)->futMc];
// Step 8. Null move search with verification search (is omitted in PV nodes) // Step 8. Null move search with verification search (is omitted in PV nodes)
if ( !PvNode if ( !PvNode
@@ -852,6 +852,8 @@ split_point_start: // At split points actual search starts from here
// Update current move (this must be done after singular extension search) // Update current move (this must be done after singular extension search)
newDepth = depth - ONE_PLY + ext; newDepth = depth - ONE_PLY + ext;
ss->futMc = 0;
// Step 13. Futility pruning (is omitted in PV nodes) // Step 13. Futility pruning (is omitted in PV nodes)
if ( !PvNode if ( !PvNode
&& !captureOrPromotion && !captureOrPromotion
@@ -874,6 +876,8 @@ split_point_start: // At split points actual search starts from here
// Value based pruning // Value based pruning
// We illogically ignore reduction condition depth >= 3*ONE_PLY for predicted depth, // We illogically ignore reduction condition depth >= 3*ONE_PLY for predicted depth,
// but fixing this made program slightly weaker. // but fixing this made program slightly weaker.
ss->futMc = moveCount;
Depth predictedDepth = newDepth - reduction<PvNode>(depth, moveCount); Depth predictedDepth = newDepth - reduction<PvNode>(depth, moveCount);
futilityValue = ss->staticEval + ss->evalMargin + futility_margin(predictedDepth, moveCount) futilityValue = ss->staticEval + ss->evalMargin + futility_margin(predictedDepth, moveCount)
+ Gain[pos.piece_moved(move)][to_sq(move)]; + Gain[pos.piece_moved(move)][to_sq(move)];

1
src/search.h
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@@ -47,6 +47,7 @@ struct Stack {
Value staticEval; Value staticEval;
Value evalMargin; Value evalMargin;
int skipNullMove; int skipNullMove;
int futMc;
}; };