Tweak LMR pruning for mandatory captures

STC giveaway
LLR: 2.96 (-2.94,2.94) [0.00,10.00]
Total: 799 W: 359 L: 264 D: 176
http://35.161.250.236:6543/tests/view/5b8a5c376e23db0fbab0dd0d

diff --git a/src/search.cpp b/src/search.cpp
index 1b79a9d..d984956 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -997,7 +997,7 @@ moves_loop: // When in check, search starts from here
       {
           Depth r = reduction<PvNode>(improving, depth, moveCount);
 
-          if (captureOrPromotion) // (~5 Elo)
+          if (captureOrPromotion || (pos.must_capture() && MoveList<CAPTURES>(pos).size())) // (~5 Elo)
           {
               // Increase reduction by comparing opponent's stat score
               if ((ss-1)->statScore >= 0)