From: Joona Kiiski <joona.kiiski@gmail.com>
Date: Wed, 17 Jun 2009 10:16:51 +0000 (+0300)
Subject: Disable use of aspiration window in known win positions
X-Git-Url: https://git.sesse.net/?a=commitdiff_plain;h=8acb1d7e4ddb9627ed3c2910f6c47f466b94ad90;p=stockfish

Disable use of aspiration window in known win positions

When we are hunting for mate, transposition table is filled in
with mate scores. Current implemenatation of aspiration search
can't cope with this very well.

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

diff --git a/src/search.cpp b/src/search.cpp
index 3382e09c..7e501fc4 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -657,7 +657,7 @@ namespace {
         // Calculate dynamic search window based on previous iterations
         Value alpha, beta;
 
-        if (MultiPV == 1 && Iteration >= 6)
+        if (MultiPV == 1 && Iteration >= 6 && abs(IterationInfo[Iteration - 1].value) < VALUE_KNOWN_WIN)
         {
             int prevDelta1 = IterationInfo[Iteration - 1].speculatedValue - IterationInfo[Iteration - 2].speculatedValue;
             int prevDelta2 = IterationInfo[Iteration - 2].speculatedValue - IterationInfo[Iteration - 3].speculatedValue;