From 6bc16f3ff162a46e5c06f8857865472757e46bf0 Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Sun, 18 Sep 2011 19:50:42 +0100 Subject: [PATCH] Update killers after a TT hit Almost no increase but seems the logic thing to do. After 16707 games 2771 - 2595 - 11341 ELO +3 (+- 3.2) Signed-off-by: Marco Costalba --- src/search.cpp | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/src/search.cpp b/src/search.cpp index 44084753..0e3ba85c 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -780,8 +780,18 @@ namespace { : can_return_tt(tte, depth, beta, ss->ply))) { TT.refresh(tte); - ss->bestMove = ttMove; // Can be MOVE_NONE - return value_from_tt(tte->value(), ss->ply); + ss->bestMove = move = ttMove; // Can be MOVE_NONE + value = value_from_tt(tte->value(), ss->ply); + + if ( value >= beta + && move + && !pos.move_is_capture_or_promotion(move) + && move != ss->killers[0]) + { + ss->killers[1] = ss->killers[0]; + ss->killers[0] = move; + } + return value; } // Step 5. Evaluate the position statically and update parent's gain statistics -- 2.39.2