From 62d3106caa2f5acf5ba32500cc19912b8f10612c Mon Sep 17 00:00:00 2001 From: UnaiCorzo Date: Sat, 25 Jul 2020 22:30:05 +0200 Subject: [PATCH] Remove late irreversible move extension We simplify away the late irreversible move extension, which does not seem to be necessary in the current master. STC LLR: 2.93 (-2.94,2.94) {-1.50,0.50} Total: 38584 W: 7464 L: 7342 D: 23778 Ptnml(0-2): 581, 4328, 9365, 4424, 594 https://tests.stockfishchess.org/tests/view/5f1c9669c09435d870cb9de9 LTC LLR: 2.94 (-2.94,2.94) {-1.50,0.50} Total: 27840 W: 3417 L: 3353 D: 21070 Ptnml(0-2): 120, 2315, 8994, 2363, 128 https://tests.stockfishchess.org/tests/view/5f1d2e22c09435d870cb9e21 closes https://github.com/official-stockfish/Stockfish/pull/2836 bench: 4829420 --- src/search.cpp | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/src/search.cpp b/src/search.cpp index 17ccab92..6ec4d803 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -1067,7 +1067,7 @@ moves_loop: // When in check, search starts from here // search of (alpha-s, beta-s), and just one fails high on (alpha, beta), // then that move is singular and should be extended. To verify this we do // a reduced search on all the other moves but the ttMove and if the - // result is lower than ttValue minus a margin then we will extend the ttMove. + // result is lower than ttValue minus a margin, then we will extend the ttMove. if ( depth >= 6 && move == ttMove && !rootNode @@ -1131,12 +1131,6 @@ moves_loop: // When in check, search starts from here if (type_of(move) == CASTLING) extension = 1; - // Late irreversible move extension - if ( move == ttMove - && pos.rule50_count() > 80 - && (captureOrPromotion || type_of(movedPiece) == PAWN)) - extension = 2; - // Add extension to new depth newDepth += extension; -- 2.39.2