Just blockSq, not forward file. Bench: 3377831 (#2240)

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index cf478909649ed0419c172ed9b7bfadebeca4d246..9a67a8e429024aa8f5453281c450aacbe322028d 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -133,6 +133,7 @@ namespace {
   };
 
   // Assorted bonuses and penalties
+  constexpr Score AttacksOnSpaceArea = S(  4,  0);
   constexpr Score BishopPawns        = S(  3,  7);
   constexpr Score CorneredBishop     = S( 50, 50);
   constexpr Score FlankAttacks       = S(  8,  0);
@@ -141,7 +142,7 @@ namespace {
   constexpr Score KnightOnQueen      = S( 16, 12);
   constexpr Score LongDiagonalBishop = S( 45,  0);
   constexpr Score MinorBehindPawn    = S( 18,  3);
-  constexpr Score Outpost            = S( 36, 12);
+  constexpr Score Outpost            = S( 18,  6);
   constexpr Score PawnlessFlank      = S( 17, 95);
   constexpr Score RestrictedPiece    = S(  7,  7);
   constexpr Score RookOnPawn         = S( 10, 32);
@@ -221,7 +222,7 @@ namespace {
     constexpr Color     Them = (Us == WHITE ? BLACK : WHITE);
     constexpr Direction Up   = (Us == WHITE ? NORTH : SOUTH);
     constexpr Direction Down = (Us == WHITE ? SOUTH : NORTH);
-    constexpr Bitboard LowRanks = (Us == WHITE ? Rank2BB | Rank3BB: Rank7BB | Rank6BB);
+    constexpr Bitboard LowRanks = (Us == WHITE ? Rank2BB | Rank3BB : Rank7BB | Rank6BB);
 
     const Square ksq = pos.square<KING>(Us);
 
@@ -304,10 +305,10 @@ namespace {
             // Bonus if piece is on an outpost square or can reach one
             bb = OutpostRanks & attackedBy[Us][PAWN] & ~pe->pawn_attacks_span(Them);
             if (bb & s)
-                score += Outpost * (Pt == KNIGHT ? 2 : 1);
+                score += Outpost * (Pt == KNIGHT ? 4 : 2);
 
             else if (bb & b & ~pos.pieces(Us))
-                score += Outpost / (Pt == KNIGHT ? 1 : 2);
+                score += Outpost * (Pt == KNIGHT ? 2 : 1);
 
             // Knight and Bishop bonus for being right behind a pawn
             if (shift<Down>(pos.pieces(PAWN)) & s)
@@ -560,7 +561,7 @@ namespace {
     b &= ~attackedBy[Them][PAWN] & safe;
 
     // Bonus for safe pawn threats on the next move
-    b = pawn_attacks_bb<Us>(b) & pos.pieces(Them);
+    b = pawn_attacks_bb<Us>(b) & nonPawnEnemies;
     score += ThreatByPawnPush * popcount(b);
 
     // Our safe or protected pawns
@@ -604,8 +605,7 @@ namespace {
       return std::min(distance(pos.square<KING>(c), s), 5);
     };
 
-    Bitboard b, bb, squaresToQueen, defendedSquares, unsafeSquares;
-    Bitboard wideUnsafeSquares;
+    Bitboard b, bb, squaresToQueen, unsafeSquares;
     Score score = SCORE_ZERO;
 
     b = pe->passed_pawns(Us);
@@ -622,7 +622,7 @@ namespace {
 
         if (r > RANK_3)
         {
-            int w = (r-2) * (r-2) + 2;
+            int w = 5 * r - 13;
             Square blockSq = s + Up;
 
             // Adjust bonus based on the king's proximity
@@ -636,30 +636,24 @@ namespace {
             // If the pawn is free to advance, then increase the bonus
             if (pos.empty(blockSq))
             {
-                // If there is a rook or queen attacking/defending the pawn from behind,
-                // consider all the squaresToQueen. Otherwise consider only the squares
-                // in the pawn's path attacked or occupied by the enemy.
-                defendedSquares = unsafeSquares = squaresToQueen = forward_file_bb(Us, s);
-                wideUnsafeSquares = AllSquares;
+                squaresToQueen = forward_file_bb(Us, s);
+                unsafeSquares = passed_pawn_span(Us, s);
 
                 bb = forward_file_bb(Them, s) & pos.pieces(ROOK, QUEEN);
 
-                if (!(pos.pieces(Us) & bb))
-                    defendedSquares &= attackedBy[Us][ALL_PIECES];
-
                 if (!(pos.pieces(Them) & bb))
                     unsafeSquares &= attackedBy[Them][ALL_PIECES] | pos.pieces(Them);
-                      
-                if (!unsafeSquares)
-                    wideUnsafeSquares = (attackedBy[Them][ALL_PIECES] | pos.pieces(Them)) 
-                                       & (shift<WEST>(squaresToQueen) | shift<EAST>(squaresToQueen));
 
-                // If there aren't any enemy attacks, assign a big bonus. Otherwise
-                // assign a smaller bonus if the block square isn't attacked.
-                int k = !wideUnsafeSquares ? 35 : !unsafeSquares ? 20 : !(unsafeSquares & blockSq) ? 9 : 0;
+                // If there are no enemy attacks on passed pawn span, assign a big bonus.
+                // Otherwise assign a smaller bonus if the path to queen is not attacked
+                // and even smaller bonus if it is attacked but block square is not.
+                int k = !unsafeSquares                    ? 35 :
+                        !(unsafeSquares & squaresToQueen) ? 20 :
+                        !(unsafeSquares & blockSq)        ?  9 :
+                                                             0 ;
 
-                // Assign a larger bonus if the block square is defended.
-                if (defendedSquares & blockSq)
+                // Assign a larger bonus if the block square is defended
+                if ((pos.pieces(Us) & bb) || (attackedBy[Us][ALL_PIECES] & blockSq))
                     k += 5;
 
                 bonus += make_score(k * w, k * w);
@@ -669,7 +663,7 @@ namespace {
         // Scale down bonus for candidate passers which need more than one
         // pawn push to become passed, or have a pawn in front of them.
         if (   !pos.pawn_passed(Us, s + Up)
-            || (pos.pieces(PAWN) & forward_file_bb(Us, s)))
+            || (pos.pieces(PAWN) & (s + Up)))
             bonus = bonus / 2;
 
         score += bonus + PassedFile[file_of(s)];
@@ -715,6 +709,8 @@ namespace {
     int weight = pos.count<ALL_PIECES>(Us) - 1;
     Score score = make_score(bonus * weight * weight / 16, 0);
 
+    score -= AttacksOnSpaceArea * popcount(attackedBy[Them][ALL_PIECES] & behind & safe);
+
     if (T)
         Trace::add(SPACE, Us, score);