LMR Tweak

VoyagerOne · snicolet · commit dc243a3c880d · 2019-07-25T08:46:26.000+02:00
Reset statScore to zero if negative and most stats shows >= 0 STC: LLR: 2.95 (-2.94,2.94) [0.50,4.50] Total: 23097 W: 5242 L: 4963 D: 12892 http://tests.stockfishchess.org/tests/view/5d31dd650ebc5925cf0e598f LTC: LLR: 2.95 (-2.94,2.94) [0.00,3.50] Total: 227597 W: 39013 L: 38191 D: 150393 http://tests.stockfishchess.org/tests/view/5d31fcdf0ebc5925cf0e5c13 Closes #2252 Bench: 3242229
diff --git a/src/search.cpp b/src/search.cpp
@@ -1114,6 +1114,13 @@ namespace {
                              + (*contHist[3])[movedPiece][to_sq(move)]
                              - 4000;
 
+              // Reset statScore to zero if negative and most stats shows >= 0
+              if (    ss->statScore < 0
+                  && (*contHist[0])[movedPiece][to_sq(move)] >= 0
+                  && (*contHist[1])[movedPiece][to_sq(move)] >= 0
+                  && thisThread->mainHistory[us][from_to(move)] >= 0)
+                  ss->statScore = 0;
+
               // Decrease/increase reduction by comparing opponent's stat score (~10 Elo)
               if (ss->statScore >= 0 && (ss-1)->statScore < 0)
                   r -= ONE_PLY;
