Evaluation drift

Increase evaluation score with ply.

After 940 games at 1+0

Mod vs Orig +247 =487 -206  +15 ELO

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

diff --git a/src/search.cpp b/src/search.cpp
index b4c0837..39ed624 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1543,7 +1543,11 @@ namespace {
         staticValue = tte->value();
     }
     else
+    {
         staticValue = evaluate(pos, ei, threadID);
+        if (!value_is_mate(staticValue + Value(ply)))
+            staticValue += Value(ply);
+    }
 
     if (ply == PLY_MAX - 1)
         return evaluate(pos, ei, threadID);