From 6247f27a0548562c122f658082d31f535208d603 Mon Sep 17 00:00:00 2001 From: Joona Kiiski Date: Thu, 21 Jan 2010 22:45:38 +0200 Subject: [PATCH] MaxGain based futility pruning for captures Signed-off-by: Marco Costalba --- src/search.cpp | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/src/search.cpp b/src/search.cpp index 6173a9a4..f259ab70 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -1556,6 +1556,28 @@ namespace { // Update current move movesSearched[moveCount++] = ss[ply].currentMove = move; + // Futility pruning for captures + Color them = opposite_color(pos.side_to_move()); + + if ( useFutilityPruning + && !dangerous + && pos.move_is_capture(move) + && !pos.move_is_check(move, ci) + && !move_is_promotion(move) + && move != ttMove + && !move_is_ep(move) + && (pos.type_of_piece_on(move_to(move)) != PAWN || !pos.pawn_is_passed(them, move_to(move)))) // Do not prune passed pawn captures + { + int preFutilityValueMargin = 0; + + if (newDepth >= OnePly) + preFutilityValueMargin = 112 * bitScanReverse32(int(newDepth) * int(newDepth) / 2); + + if (ss[ply].eval + pos.endgame_value_of_piece_on(move_to(move)) + preFutilityValueMargin + ei.futilityMargin + 90 < beta) + continue; + } + + // Futility pruning if ( useFutilityPruning && !dangerous -- 2.39.2