From 27139dedac14af400f5b18e2ab50aca3f8cf0e33 Mon Sep 17 00:00:00 2001 From: Michael Chaly Date: Sat, 19 Feb 2022 18:24:11 +0300 Subject: [PATCH] Adjust usage of LMR for 2nd move in move ordering Current master prohibits usage of LMR for 2nd move at rootNode. This patch also disables LMR for 2nd move not only at rootNode but also at first PvNode that is a reply to rootNode. passed STC: https://tests.stockfishchess.org/tests/view/620e8c9026f5b17ec885143a LLR: 2.94 (-2.94,2.94) <0.00,2.50> Total: 54096 W: 14305 L: 13996 D: 25795 Ptnml(0-2): 209, 6075, 14192, 6342, 230 passed LTC: https://tests.stockfishchess.org/tests/view/620eb327b1792e8985f81fb8 LLR: 2.94 (-2.94,2.94) <0.50,3.00> Total: 110864 W: 29602 L: 29156 D: 52106 Ptnml(0-2): 112, 11147, 32455, 11619, 99 closes https://github.com/official-stockfish/Stockfish/pull/3940 bench 6820724 --- src/search.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/search.cpp b/src/search.cpp index e6420931..6785ba4c 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -1136,7 +1136,7 @@ moves_loop: // When in check, search starts here // been searched. In general we would like to reduce them, but there are many // cases where we extend a son if it has good chances to be "interesting". if ( depth >= 2 - && moveCount > 1 + rootNode + && moveCount > 1 + (PvNode && ss->ply <= 1) && ( !ss->ttPv || !captureOrPromotion || (cutNode && (ss-1)->moveCount > 1))) -- 2.39.2