From: Marco Costalba <mcostalba@gmail.com>
Date: Mon, 13 Oct 2008 05:15:48 +0000 (+0200)
Subject: Add a second margin to razoring
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=4fa5dd4db55ba9fde841120fc8fbcd99f6540eb4;ds=inline

Add a second margin to razoring

Razor on ply one if the advantage is more then a pawn,
the only way to gap the advantage is to capture, so
go directly in quiesce.

This seems to have a positive effect.

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

diff --git a/src/search.cpp b/src/search.cpp
index 8279d157..10aa196a 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1122,7 +1122,8 @@ namespace {
         }
     }
     // Null move search not allowed, try razoring
-    else if (depth < RazorDepth && approximateEval < beta - RazorMargin)
+    else if (  (approximateEval < beta - RazorMargin && depth < RazorDepth)
+             ||(approximateEval < beta - PawnValueMidgame && depth <= OnePly))
     {
         Value v = qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
         if (v < beta)