Decrease reductions in Lmr for some Pv nodes

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 6785ba4c6b44d2bb3db6fc42bde736971fcd6d09..3008079e9c4ade413f2ee829ba5af2a7b8ad4f42 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -863,7 +863,7 @@ namespace {
     {
         assert(probCutBeta < VALUE_INFINITE);
 
-        MovePicker mp(pos, ttMove, probCutBeta - ss->staticEval, &captureHistory);
+        MovePicker mp(pos, ttMove, probCutBeta - ss->staticEval, depth - 3, &captureHistory);
         bool ttPv = ss->ttPv;
         ss->ttPv = false;
 
@@ -1166,6 +1166,11 @@ moves_loop: // When in check, search starts here
           if (ttCapture)
               r++;
 
+          // Decrease reduction at PvNodes if bestvalue
+          // is vastly different from static evaluation
+          if (PvNode && !ss->inCheck && abs(ss->staticEval - bestValue) > 250)
+              r--;
+
           ss->statScore =  thisThread->mainHistory[us][from_to(move)]
                          + (*contHist[0])[movedPiece][to_sq(move)]
                          + (*contHist[1])[movedPiece][to_sq(move)]