Dynamic draw value

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index c84ad24b2a8b99b0993904e017ff53d17fdb0123..668fd0955687523cd8d8779dccb1c65aea64e6fb 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -206,10 +206,10 @@ void Search::think() {
       }
   }
 
-  if (Options["Contempt Factor"] && !Options["UCI_AnalyseMode"])
+  if (!Options["UCI_AnalyseMode"])
   {
-      int cf = Options["Contempt Factor"] * PawnValueMg / 100; // From centipawns
-      cf = cf * Material::game_phase(RootPos) / PHASE_MIDGAME; // Scale down with phase
+      // Dynamic draw value: try to avoid repetition draws at early midgame
+      int cf = std::max(70 - RootPos.game_ply(), 0);
       DrawValue[ RootColor] = VALUE_DRAW - Value(cf);
       DrawValue[~RootColor] = VALUE_DRAW + Value(cf);
   }