Weak queen protection

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index ceba25881058d8135a0f50cdff3afc44d56ea4de..06366e09501608c59743cf82f0e0507c36636175 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -114,11 +114,11 @@ namespace {
   // which piece type attacks which one. Attacks on lesser pieces which are
   // pawn-defended are not considered.
   constexpr Score ThreatByMinor[PIECE_TYPE_NB] = {
-    S(0, 0), S(6, 32), S(59, 41), S(79, 56), S(90, 119), S(79, 161)
+    S(0, 0), S(5, 32), S(57, 41), S(77, 56), S(88, 119), S(79, 161)
   };
 
   constexpr Score ThreatByRook[PIECE_TYPE_NB] = {
-    S(0, 0), S(3, 44), S(38, 71), S(38, 61), S(0, 38), S(51, 38)
+    S(0, 0), S(2, 44), S(36, 71), S(36, 61), S(0, 38), S(51, 38)
   };
 
   // PassedRank[Rank] contains a bonus according to the rank of a passed pawn
@@ -139,7 +139,6 @@ namespace {
   constexpr Score PassedFile         = S( 11,  8);
   constexpr Score PawnlessFlank      = S( 17, 95);
   constexpr Score RestrictedPiece    = S(  7,  7);
-  constexpr Score ReachableOutpost   = S( 32, 10);
   constexpr Score RookOnQueenFile    = S(  7,  6);
   constexpr Score SliderOnQueen      = S( 59, 18);
   constexpr Score ThreatByKing       = S( 24, 89);
@@ -296,7 +295,7 @@ namespace {
                 score += Outpost * (Pt == KNIGHT ? 2 : 1);
 
             else if (Pt == KNIGHT && bb & b & ~pos.pieces(Us))
-                score += ReachableOutpost;
+                score += Outpost;
 
             // Knight and Bishop bonus for being right behind a pawn
             if (shift<Down>(pos.pieces(PAWN)) & s)
@@ -517,6 +516,9 @@ namespace {
         b =  ~attackedBy[Them][ALL_PIECES]
            | (nonPawnEnemies & attackedBy2[Us]);
         score += Hanging * popcount(weak & b);
+
+        // Additional bonus if weak piece is only protected by a queen
+        score += make_score(14, 0) * popcount(weak & attackedBy[Them][QUEEN]);
     }
 
     // Bonus for restricting their piece moves