From b939788f9de55051e0dd43e5943a0cde0f2be14e Mon Sep 17 00:00:00 2001 From: Guenther Demetz Date: Mon, 4 Jun 2018 09:10:30 +0200 Subject: [PATCH 1/1] Remove a superfluous subtrahend The '- 1' subtrahend was introduced for guarding against null move search at root, which would be nonsense. But this is actually already guaranteed by the !PvNode condition. This followed from the discussion in pull request 1609: https://github.com/official-stockfish/Stockfish/pull/1609 No functional change --- src/search.cpp | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/search.cpp b/src/search.cpp index 0574da58..93651cc0 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -751,7 +751,7 @@ namespace { && ss->staticEval >= beta - 36 * depth / ONE_PLY + 225 && !excludedMove && pos.non_pawn_material(us) - && (ss->ply > thisThread->nmpMinPly || us != thisThread->nmpColor)) + && (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor)) { assert(eval - beta >= 0); @@ -780,7 +780,7 @@ namespace { // Do verification search at high depths, with null move pruning disabled // for us, until ply exceeds nmpMinPly. - thisThread->nmpMinPly = ss->ply + 3 * (depth-R) / 4 - 1; + thisThread->nmpMinPly = ss->ply + 3 * (depth-R) / 4; thisThread->nmpColor = us; Value v = search(pos, ss, beta-1, beta, depth-R, false); -- 2.39.2