CMH Fix: Exclude captures for TT move refutation penalty

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 727990dc9d354b753004ae37b61afd7f2c1d28ad..865e477144042c2a99577ac8179e066718016585 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1428,7 +1428,7 @@ moves_loop: // When in check and at SpNode search starts from here
     }
 
     // Extra penalty for TT move in previous ply when it gets refuted
     }
 
     // Extra penalty for TT move in previous ply when it gets refuted

-    if (is_ok((ss-2)->currentMove) && (ss-1)->currentMove == (ss-1)->ttMove)
+    if (is_ok((ss-2)->currentMove) && (ss-1)->currentMove == (ss-1)->ttMove && !pos.captured_piece_type())

     {
         Square prevPrevSq = to_sq((ss-2)->currentMove);
         HistoryStats& ttMoveCmh = CounterMovesHistory[pos.piece_on(prevPrevSq)][prevPrevSq];
     {
         Square prevPrevSq = to_sq((ss-2)->currentMove);
         HistoryStats& ttMoveCmh = CounterMovesHistory[pos.piece_on(prevPrevSq)][prevPrevSq];