Reduce more CUT nodes only if parent node is reduced

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index a10e1180c344a3af45a23bf293386d27cc48ddbf..bfab6a4e1cd2829408f1e0d849f3962ab9fd77db 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -949,7 +949,7 @@ split_point_start: // At split points actual search starts from here
       {
           ss->reduction = reduction<PvNode>(depth, moveCount);
 
       {
           ss->reduction = reduction<PvNode>(depth, moveCount);
 

-          if (!PvNode && cutNode)
+          if (!PvNode && cutNode && (ss-1)->reduction)

               ss->reduction += ONE_PLY;
 
           if (move == countermoves[0] || move == countermoves[1])
               ss->reduction += ONE_PLY;
 
           if (move == countermoves[0] || move == countermoves[1])