Decrease reductions in Lmr for some Pv nodes

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index a6552daf2a0e290b63b5720dd8e1c8b90fede2d9..3008079e9c4ade413f2ee829ba5af2a7b8ad4f42 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -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)]