From: Marco Costalba <mcostalba@gmail.com>
Date: Fri, 18 Sep 2009 10:12:22 +0000 (+0200)
Subject: Don't compensate TT for evaluation drift
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=7c55b0e880b68c0242d27a0471f8d535f02703f0

Don't compensate TT for evaluation drift

It seems that it works better without compensation
of drifted value when saving static evaluation in TT.

After 818 games at 1+0

Mod vs Orig +217 =429 -172 52.75%  431.5/818  +19 ELO

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

diff --git a/src/search.cpp b/src/search.cpp
index 7bc90b14..ac4d85b6 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1556,7 +1556,7 @@ namespace {
     {
         // Store the score to avoid a future costly evaluation() call
         if (!isCheck && !tte && ei.futilityMargin == 0)
-            TT.store(pos.get_key(), bestValue - ply, VALUE_TYPE_EVAL, Depth(-127*OnePly), MOVE_NONE);
+            TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EVAL, Depth(-127*OnePly), MOVE_NONE);
 
         return bestValue;
     }