X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=78a1f7b6eb9e038a5c24f415dd127a2ddb67c13b;hp=6e37fba1e524f8725d9737cab9568ea5d7081e4d;hb=027626db1e449597ba2211a0819f251beda37b88;hpb=04a320666efce725ef66d1a84aaef493a880153d

diff --git a/src/search.cpp b/src/search.cpp
index 6e37fba1..78a1f7b6 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1058,7 +1058,7 @@ moves_loop: // When in check, search starts from here
                   && captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] < 0)
                   continue;
 
-              // See based pruning
+              // SEE based pruning
               if (!pos.see_ge(move, Value(-221) * depth)) // (~25 Elo)
                   continue;
           }
@@ -1161,7 +1161,7 @@ moves_loop: // When in check, search starts from here
           if (thisThread->ttHitAverage > 509 * TtHitAverageResolution * TtHitAverageWindow / 1024)
               r--;
 
-          // Reduction if other threads are searching this position
+          // Increase reduction if other threads are searching this position
           if (th.marked())
               r++;
 
@@ -1169,6 +1169,10 @@ moves_loop: // When in check, search starts from here
           if (ss->ttPv)
               r -= 2;
 
+          // Increase reduction at root and non-PV nodes when the best move does not change frequently
+          if ((rootNode || !PvNode) && depth > 10 && thisThread->bestMoveChanges <= 2)
+              r++;
+
           if (moveCountPruning && !formerPv)
               r++;
 
@@ -1525,7 +1529,7 @@ moves_loop: // When in check, search starts from here
       moveCount++;
 
       // Futility pruning
-      if (   !ss->inCheck
+      if (    bestValue > VALUE_TB_LOSS_IN_MAX_PLY
           && !givesCheck
           &&  futilityBase > -VALUE_KNOWN_WIN
           && !pos.advanced_pawn_push(move))
@@ -1552,7 +1556,7 @@ moves_loop: // When in check, search starts from here
       }
 
       // Do not search moves with negative SEE values
-      if (   !ss->inCheck
+      if (    bestValue > VALUE_TB_LOSS_IN_MAX_PLY
           && !(givesCheck && pos.is_discovery_check_on_king(~pos.side_to_move(), move))
           && !pos.see_ge(move))
           continue;