Give bonus for rooks that are alligned with enemy kingring

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index d972db5a1ccc26f178e962542c358a432a383073..8e8cc0912e57ddd4e37c12cb579631eaee9de289 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -91,15 +91,15 @@ namespace {
   // MobilityBonus[PieceType-2][attacked] contains bonuses for middle and end game,
   // indexed by piece type and number of attacked squares in the mobility area.
   constexpr Score MobilityBonus[][32] = {
-    { S(-62,-81), S(-53,-56), S(-12,-30), S( -4,-14), S(  3,  8), S( 13, 15), // Knight
-      S( 22, 23), S( 28, 27), S( 33, 33) },
+    { S(-62,-81), S(-53,-56), S(-12,-31), S( -4,-16), S(  3,  5), S( 13, 11), // Knight
+      S( 22, 17), S( 28, 20), S( 33, 25) },
     { S(-48,-59), S(-20,-23), S( 16, -3), S( 26, 13), S( 38, 24), S( 51, 42), // Bishop
       S( 55, 54), S( 63, 57), S( 63, 65), S( 68, 73), S( 81, 78), S( 81, 86),
       S( 91, 88), S( 98, 97) },
     { S(-60,-78), S(-20,-17), S(  2, 23), S(  3, 39), S(  3, 70), S( 11, 99), // Rook
       S( 22,103), S( 31,121), S( 40,134), S( 40,139), S( 41,158), S( 48,164),
       S( 57,168), S( 57,169), S( 62,172) },
-    { S(-34,-36), S(-15,-21), S(-10, -1), S(-10, 22), S( 20, 41), S( 23, 56), // Queen
+    { S(-30,-48), S(-12,-30), S( -8, -7), S( -9, 19), S( 20, 40), S( 23, 55), // Queen
       S( 23, 59), S( 35, 75), S( 38, 78), S( 53, 96), S( 64, 96), S( 65,100),
       S( 65,121), S( 66,127), S( 67,131), S( 67,133), S( 72,136), S( 72,141),
       S( 77,147), S( 79,150), S( 93,151), S(108,168), S(108,168), S(108,171),
@@ -143,6 +143,7 @@ namespace {
   constexpr Score PassedFile          = S( 11,  8);
   constexpr Score PawnlessFlank       = S( 17, 95);
   constexpr Score RestrictedPiece     = S(  7,  7);
+  constexpr Score RookOnKingRing      = S( 16,  0);
   constexpr Score RookOnQueenFile     = S(  5,  9);
   constexpr Score SliderOnQueen       = S( 59, 18);
   constexpr Score ThreatByKing        = S( 24, 89);
@@ -287,6 +288,8 @@ namespace {
             kingAttackersWeight[Us] += KingAttackWeights[Pt];
             kingAttacksCount[Us] += popcount(b & attackedBy[Them][KING]);
         }
+        else if (Pt == ROOK && (file_bb(s) & kingRing[Them]))
+            score += RookOnKingRing;
 
         int mob = popcount(b & mobilityArea[Us]);
 
@@ -311,7 +314,7 @@ namespace {
 
             if (Pt == BISHOP)
             {
-                // Penalty according to number of pawns on the same color square as the
+                // Penalty according to the number of our pawns on the same color square as the
                 // bishop, bigger when the center files are blocked with pawns and smaller
                 // when the bishop is outside the pawn chain.
                 Bitboard blocked = pos.pieces(Us, PAWN) & shift<Down>(pos.pieces());
@@ -591,25 +594,22 @@ namespace {
       return std::min(distance(pos.square<KING>(c), s), 5);
     };
 
-    Bitboard b, bb, squaresToQueen, unsafeSquares, candidatePassers, leverable;
+    Bitboard b, bb, squaresToQueen, unsafeSquares, blockedPassers, helpers;
     Score score = SCORE_ZERO;
 
     b = pe->passed_pawns(Us);
 
-    candidatePassers = b & shift<Down>(pos.pieces(Them, PAWN));
-    if (candidatePassers)
+    blockedPassers = b & shift<Down>(pos.pieces(Them, PAWN));
+    if (blockedPassers)
     {
-        // Can we lever the blocker of a candidate passer?
-        leverable =  shift<Up>(pos.pieces(Us, PAWN))
-                   & ~pos.pieces(Them)
-                   & (~attackedBy2[Them] | attackedBy[Us][ALL_PIECES])
-                   & (~(attackedBy[Them][KNIGHT] | attackedBy[Them][BISHOP])
-                     | (attackedBy[Us  ][KNIGHT] | attackedBy[Us  ][BISHOP]));
-
-        // Remove candidate otherwise
-        b &= ~candidatePassers
-            | shift<WEST>(leverable)
-            | shift<EAST>(leverable);
+        helpers =  shift<Up>(pos.pieces(Us, PAWN))
+                 & ~pos.pieces(Them)
+                 & (~attackedBy2[Them] | attackedBy[Us][ALL_PIECES]);
+
+        // Remove blocked candidate passers that don't have help to pass
+        b &=  ~blockedPassers
+            | shift<WEST>(helpers)
+            | shift<EAST>(helpers);
     }
 
     while (b)
@@ -733,7 +733,7 @@ namespace {
 
     // Compute the initiative bonus for the attacking side
     int complexity =   9 * pe->passed_count()
-                    + 11 * pos.count<PAWN>()
+                    + 12 * pos.count<PAWN>()
                     +  9 * outflanking
                     + 21 * pawnsOnBothFlanks
                     + 24 * infiltration