From c43425b0b1167665b2f9520690e639c80977c067 Mon Sep 17 00:00:00 2001 From: Shawn Xu Date: Wed, 8 May 2024 14:26:01 -0700 Subject: [PATCH] Simplify Away Negative Extension This patch simplifies away the negative extension applied when the value returned by the transposition table is assumed to fail low over the value of reduced search. Passed STC: LLR: 2.99 (-2.94,2.94) <-1.75,0.25> Total: 248736 W: 64293 L: 64302 D: 120141 Ptnml(0-2): 925, 29833, 62831, 29884, 895 https://tests.stockfishchess.org/tests/view/663bee3bca93dad645f7f64a Passed LTC: LLR: 2.94 (-2.94,2.94) <-1.75,0.25> Total: 254970 W: 64289 L: 64308 D: 126373 Ptnml(0-2): 110, 28428, 70422, 28421, 104 https://tests.stockfishchess.org/tests/view/663c11f0c0b75d7f7b97d4bb closes https://github.com/official-stockfish/Stockfish/pull/5226 Bench: 2353057 --- src/search.cpp | 4 ---- 1 file changed, 4 deletions(-) diff --git a/src/search.cpp b/src/search.cpp index fdf9871cd0c..4572ffc900d 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -1087,10 +1087,6 @@ Value Search::Worker::search( // If we are on a cutNode but the ttMove is not assumed to fail high over current beta (~1 Elo) else if (cutNode) extension = -2; - - // If the ttMove is assumed to fail low over the value of the reduced search (~1 Elo) - else if (ttValue <= value) - extension = -1; } // Extension for capturing the previous moved piece (~0 Elo on STC, ~1 Elo on LTC)