From: Uri Blass <uriblass@gmail.com>
Date: Tue, 10 Sep 2013 06:37:23 +0000 (+0200)
Subject: Extend checks more in losing positions
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=738c5595adefe397d8389fb315908e7d2f6ab40c;hp=bebd6e16f6e8be116419632635baf9c0d8b7ba4e;ds=sidebyside

Extend checks more in losing positions

Passed both short TC:
LLR: 2.98 (-2.94,2.94) [-1.50,4.50]
Total: 3974 W: 860 L: 741 D: 2373

And long TC:
LLR: 2.96 (-2.94,2.94) [0.00,6.00]
Total: 16807 W: 2917 L: 2733 D: 11157

bench: 3767999
---

diff --git a/src/search.cpp b/src/search.cpp
index 4b0a9fe8..f64f55f0 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -837,7 +837,7 @@ moves_loop: // When in check and at SpNode search starts from here
           ext = ONE_PLY;
 
       else if (givesCheck && pos.see_sign(move) >= 0)
-          ext = ONE_PLY / 2;
+          ext = inCheck || ss->staticEval < VALUE_ZERO ? ONE_PLY : ONE_PLY / 2;
 
       // Singular extension search. If all moves but one fail low on a search of
       // (alpha-s, beta-s), and just one fails high on (alpha, beta), then that move