Futile pruning simplification

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index f412d9d6f1a1573fefbadeccdbed2d7513115ca9..187f21694ef932d543eb474f8914719d9c2a46f1 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -907,7 +907,7 @@ namespace {
         && !ttMove)
         depth -= 2;
 
-moves_loop: // When in check, search starts from here
+moves_loop: // When in check, search starts here
 
     ttCapture = ttMove && pos.capture_or_promotion(ttMove);
 
@@ -1017,17 +1017,13 @@ moves_loop: // When in check, search starts from here
           {
               // Continuation history based pruning (~20 Elo)
               if (   lmrDepth < 5
-                  && (*contHist[0])[movedPiece][to_sq(move)] < CounterMovePruneThreshold
-                  && (*contHist[1])[movedPiece][to_sq(move)] < CounterMovePruneThreshold)
+                  && (*contHist[0])[movedPiece][to_sq(move)] < (depth == 1 ? 0 : -stat_bonus(depth-1))
+                  && (*contHist[1])[movedPiece][to_sq(move)] < (depth == 1 ? 0 : -stat_bonus(depth-1)))
                   continue;
 
               // Futility pruning: parent node (~5 Elo)
               if (   !ss->inCheck
-                  && ss->staticEval + 174 + 157 * lmrDepth <= alpha
-                  &&  (*contHist[0])[movedPiece][to_sq(move)]
-                    + (*contHist[1])[movedPiece][to_sq(move)]
-                    + (*contHist[3])[movedPiece][to_sq(move)]
-                    + (*contHist[5])[movedPiece][to_sq(move)] / 3 < 28255)
+                  && ss->staticEval + 174 + 157 * lmrDepth <= alpha)
                   continue;
 
               // Prune moves with negative SEE (~20 Elo)