Streamlline reduction based on movecount

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 7873e7dc552d5ec0cadb8db902df5fe186b31eb6..b68c8b7859a1a6e5a27b761b06c2b80c31ed4f80 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -947,13 +947,16 @@ moves_loop: // When in check search starts from here
           &&  moveCount > 1
           && (!captureOrPromotion || moveCountPruning))
       {
-          int mch = std::max(1, moveCount - (ss-1)->moveCount / 16);
-          Depth r = reduction<PvNode>(improving, depth, mch);
+          Depth r = reduction<PvNode>(improving, depth, moveCount);
 
           if (captureOrPromotion)
               r -= r ? ONE_PLY : DEPTH_ZERO;
           else
           {
+              // Decrease reduction if opponent's move count is high
+              if ((ss-1)->moveCount > 15)
+                  r -= ONE_PLY;
+
               // Increase reduction if ttMove is a capture
               if (ttCapture)
                   r += ONE_PLY;