Apply multicut pruning more often

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index fd690dcd9ebd0bb77b0b274a572a466df1ebfe13..a7e90a08552f7ac09f8f093b9da0907284c095f9 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1091,6 +1091,18 @@ moves_loop: // When in check, search starts from here
           // a soft bound.
           else if (singularBeta >= beta)
               return singularBeta;
+
+          // If the eval of ttMove is greater than beta we try also if there is an other move that
+          // pushes it over beta, if so also produce a cutoff
+          else if (ttValue >= beta)
+          {
+              ss->excludedMove = move;
+              value = search<NonPV>(pos, ss, beta - 1, beta, (depth + 3) / 2, cutNode);
+              ss->excludedMove = MOVE_NONE;
+
+              if (value >= beta)
+                  return beta;
+          }
       }
 
       // Check extension (~2 Elo)