Use moveCount history for reduction

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 3a54bf01b0d4e9ac41632c8f03c40a1f2ce723b7..09e12ed1bf2602dca0504e94d5a516d65f6cb33d 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -908,7 +908,8 @@ moves_loop: // When in check search starts from here
               }
 
               // Reduced depth of the next LMR search
-              int lmrDepth = std::max(newDepth - reduction<PvNode>(improving, depth, moveCount), DEPTH_ZERO) / ONE_PLY;
+              int mch = std::max(1, moveCount - (ss-1)->moveCount / 16);
+              int lmrDepth = std::max(newDepth - reduction<PvNode>(improving, depth, mch), DEPTH_ZERO) / ONE_PLY;
 
               // Countermoves based pruning
               if (   lmrDepth < 3
@@ -959,7 +960,8 @@ moves_loop: // When in check search starts from here
           &&  moveCount > 1
           && (!captureOrPromotion || moveCountPruning))
       {
-          Depth r = reduction<PvNode>(improving, depth, moveCount);
+          int mch = std::max(1, moveCount - (ss-1)->moveCount / 16);
+          Depth r = reduction<PvNode>(improving, depth, mch);
 
           if (captureOrPromotion)
               r -= r ? ONE_PLY : DEPTH_ZERO;