From: Joona Kiiski <joona.kiiski@gmail.com>
Date: Sat, 5 Feb 2011 18:24:42 +0000 (+0200)
Subject: Maximum aspiration delta of 64
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=3abff79df3c50435556d53c1b39ec3e5935b642e

Maximum aspiration delta of 64

After 9242 games
Mod vs Orig: 1483 - 1373 - 6386  ELO +4 (+- 2.9)

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

diff --git a/src/search.cpp b/src/search.cpp
index 19e6c14b..5196e862 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -657,7 +657,7 @@ namespace {
             int prevDelta1 = bestValues[iteration - 1] - bestValues[iteration - 2];
             int prevDelta2 = bestValues[iteration - 2] - bestValues[iteration - 3];
 
-            aspirationDelta = Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16);
+            aspirationDelta = Min(Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16), 64);
             aspirationDelta = (aspirationDelta + 7) / 8 * 8; // Round to match grainSize
 
             alpha = Max(bestValues[iteration - 1] - aspirationDelta, -VALUE_INFINITE);