Tweak CMH pruning

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index aeaa4336383960142e77260b7442d17659871bcb..d6239594d9165cb91578311a353e801851ac724e 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -160,7 +160,6 @@ namespace {
   constexpr Score KnightOnQueen      = S( 20, 12);
   constexpr Score LongDiagonalBishop = S( 44,  0);
   constexpr Score MinorBehindPawn    = S( 16,  0);
-  constexpr Score Overload           = S( 12,  6);
   constexpr Score PawnlessFlank      = S( 18, 94);
   constexpr Score RestrictedPiece    = S(  7,  6);
   constexpr Score RookOnPawn         = S( 10, 28);
@@ -310,7 +309,7 @@ namespace {
         attackedBy[Us][Pt] |= b;
         attackedBy[Us][ALL_PIECES] |= b;
 
-        if (b & kingRing[Them])
+        if (b & kingRing[Them] & ~double_pawn_attacks_bb<Them>(pos.pieces(Them, PAWN)))
         {
             kingAttackersCount[Us]++;
             kingAttackersWeight[Us] += KingAttackWeights[Pt];
@@ -553,10 +552,9 @@ namespace {
         if (weak & attackedBy[Us][KING])
             score += ThreatByKing;
 
-        score += Hanging * popcount(weak & ~attackedBy[Them][ALL_PIECES]);
-
-        b = weak & nonPawnEnemies & attackedBy[Them][ALL_PIECES];
-        score += Overload * popcount(b);
+        b =  ~attackedBy[Them][ALL_PIECES]
+           | (nonPawnEnemies & attackedBy2[Us]);
+        score += Hanging * popcount(weak & b);
     }
 
     // Bonus for restricting their piece moves