From: Joona Kiiski <joona.kiiski@gmail.com>
Date: Thu, 14 Jan 2010 20:58:38 +0000 (+0200)
Subject: Razor at depth one, but do razoring only when not in check
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=d4575941974ade5135971b87ff663ef4ff000de9

Razor at depth one, but do razoring only when not in check

This way razoring is always based on exact evaluation and
follows simple formula.

Joona's test results are positive:

32-bit 1CPU:

Mod - Orig: 1073 - 993

64-bit 4CPU:

Mod - Orig: 759 - 721

Functionality Signature: 11448962

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
---

diff --git a/src/search.cpp b/src/search.cpp
index 76db6d69..40808c6a 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1447,8 +1447,9 @@ namespace {
     }
     // Null move search not allowed, try razoring
     else if (   !value_is_mate(beta)
+             && !isCheck
              && depth < RazorDepth
-             && staticValue < beta - (depth > OnePly ? NullMoveMargin + 16 * depth : 2*NullMoveMargin)
+             && staticValue < beta - (NullMoveMargin + 16 * depth)
              && ss[ply - 1].currentMove != MOVE_NULL
              && ttMove == MOVE_NONE
              && !pos.has_pawn_on_7th(pos.side_to_move()))