From f4c27cda1a6874550fcbf6cf991b0b9abe43ff39 Mon Sep 17 00:00:00 2001 From: SFisGOD Date: Sat, 8 Aug 2020 03:45:08 +0800 Subject: [PATCH] Reintroduce late irreversible move extension Reintroduce vondele's late irreversible move extension for fortress keeping. This was removed when we only had classical eval. Now that we have the NNUE net, it seems that this is useful again. STC: LLR: 2.93 (-2.94,2.94) {-0.50,1.50} Total: 5352 W: 787 L: 653 D: 3912 Ptnml(0-2): 34, 451, 1579, 571, 41 https://tests.stockfishchess.org/tests/view/5f2dc8ad61e3b6af64881ff0 LTC: LLR: 2.94 (-2.94,2.94) {0.25,1.75} Total: 14416 W: 1013 L: 891 D: 12512 Ptnml(0-2): 15, 722, 5623, 822, 26 https://tests.stockfishchess.org/tests/view/5f2e0e3661e3b6af6488201e closes https://github.com/official-stockfish/Stockfish/pull/2936 Bench: 4154696 --- src/search.cpp | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/search.cpp b/src/search.cpp index 886ed52c..8be96e29 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -1134,6 +1134,12 @@ moves_loop: // When in check, search starts from here // Castling extension 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