From 96d05017354fa838462a7f8f6e25b8731e2ec400 Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Sun, 21 Dec 2008 10:42:39 +0100 Subject: [PATCH] Less aggressive razoring Use a margin to compare with beta so that positions that after the verifying qsearch have gained a lot of points are not discarded just becasue not above beta. Also remove the second condition on depth <= OnePly, it was too risky and added only a 2% more of pruned nodes. Signed-off-by: Marco Costalba --- src/search.cpp | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/src/search.cpp b/src/search.cpp index c3f96e13..054ef45d 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -1237,11 +1237,11 @@ namespace { } // Null move search not allowed, try razoring else if ( !value_is_mate(beta) - && ( (approximateEval < beta - RazorMargin && depth < RazorDepth) - ||(approximateEval < beta - PawnValueMidgame && depth <= OnePly))) + && approximateEval < beta - RazorMargin + && depth < RazorDepth) { Value v = qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID); - if (v < beta) + if (v < beta - RazorMargin / 2) return v; } -- 2.39.2