Only positive SEE

MJZ1977 · Apr 8, 2019 · 03b3f35 · 03b3f35
1 parent f2f38e5
commit 03b3f35
Showing 1 changed file with 5 additions and 4 deletions.
diff --git a/src/search.cpp b/src/search.cpp
@@ -539,7 +539,7 @@ namespace {
     Move ttMove, move, excludedMove, bestMove;
     Depth extension, newDepth;
     Value bestValue, value, ttValue, eval, maxValue;
-    bool ttHit, ttPv, inCheck, givesCheck, improving, EvalExtension;
+    bool ttHit, ttPv, inCheck, givesCheck, improving, EvalExtension, positiveSEE;
     bool captureOrPromotion, doFullDepthSearch, moveCountPruning, ttCapture;
     Piece movedPiece;
     int moveCount, captureCount, quietCount;
@@ -898,6 +898,7 @@ namespace {
       captureOrPromotion = pos.capture_or_promotion(move);
       movedPiece = pos.moved_piece(move);
       givesCheck = pos.gives_check(move);
+      positiveSEE = pos.see_ge(move);
 
       // Step 13. Extensions (~70 Elo)
 
@@ -936,7 +937,7 @@ namespace {
 
       // Check extension (~2 Elo)
       else if (    givesCheck
-               && (pos.blockers_for_king(~us) & from_sq(move) || pos.see_ge(move)))
+               && (pos.blockers_for_king(~us) & from_sq(move) || positiveSEE))
           extension = ONE_PLY;
 
       // Shuffle extension
@@ -964,9 +965,9 @@ namespace {
       {
           // Skip quiet moves if movecount exceeds our FutilityMoveCount threshold
           moveCountPruning = moveCount >= futility_move_count(improving, depth / ONE_PLY);
-          //if (moveCountPruning && EvalExtension && type_of(movedPiece) == PAWN)
+          //if (moveCountPruning && EvalExtension && type_of(movedPiece) == PAWN && positiveSEE)
           //   sync_cout << "Position : " << pos.fen() << " - Move = " << UCI::move(move, pos.is_chess960()) << sync_endl;
-          moveCountPruning &= !(EvalExtension && type_of(movedPiece) == PAWN);
+          moveCountPruning &= !(EvalExtension && type_of(movedPiece) == PAWN && positiveSEE);
 
           if (   !captureOrPromotion
               && !givesCheck