From 56e698ef8382cc837507c8910bf2409ebb4aec77 Mon Sep 17 00:00:00 2001 From: Stefan Geschwentner Date: Tue, 21 Jan 2020 09:28:58 +0100 Subject: [PATCH 1/1] Less reduction for escape moves at ttPv nodes At expected PV nodes or nodes which marked as PV node in the hash table, reduce escape moves even one ply less. STC: LLR: 2.94 (-2.94,2.94) {-1.00,3.00} Total: 31795 W: 6140 L: 5953 D: 19702 Ptnml(0-2): 525, 3625, 7455, 3695, 583 http://tests.stockfishchess.org/tests/view/5e25d77fc3b97aa0d75bc013 LTC: LLR: 2.94 (-2.94,2.94) {0.00,2.00} Total: 43975 W: 5708 L: 5454 D: 32813 Ptnml(0-2): 314, 4012, 13070, 4242, 325 http://tests.stockfishchess.org/tests/view/5e2618c1c3b97aa0d75bc03c Closes https://github.com/official-stockfish/Stockfish/pull/2505 Bench: 4475583 --- src/search.cpp | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/src/search.cpp b/src/search.cpp index 21df156c..3bd1a92d 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -625,7 +625,7 @@ namespace { Move ttMove, move, excludedMove, bestMove; Depth extension, newDepth; Value bestValue, value, ttValue, eval, maxValue; - bool ttHit, ttPv, inCheck, givesCheck, improving , didLMR, priorCapture; + bool ttHit, ttPv, inCheck, givesCheck, improving, didLMR, priorCapture; bool captureOrPromotion, doFullDepthSearch, moveCountPruning, ttCapture, singularLMR; Piece movedPiece; int moveCount, captureCount, quietCount; @@ -825,7 +825,6 @@ namespace { && eval <= alpha - RazorMargin) return qsearch(pos, ss, alpha, beta); - // (~13 Elo) improving = (ss-2)->staticEval == VALUE_NONE ? (ss->staticEval > (ss-4)->staticEval || (ss-4)->staticEval == VALUE_NONE) : ss->staticEval > (ss-2)->staticEval; @@ -1161,7 +1160,7 @@ moves_loop: // When in check, search starts from here // hence break make_move(). (~2 Elo) else if ( type_of(move) == NORMAL && !pos.see_ge(reverse_move(move))) - r -= 2; + r -= 2 + ttPv; ss->statScore = thisThread->mainHistory[us][from_to(move)] + (*contHist[0])[movedPiece][to_sq(move)] -- 2.39.2