{ S(18, 5), S(27, 8) } // Bishops
};
- // Threat[defended/weak][minor/rook attacking][attacked PieceType] contains
+ // Threat[minor/rook][attacked PieceType] contains
// bonuses according to which piece type attacks which one.
- const Score Threat[][2][PIECE_TYPE_NB] = {
- { { S(0, 0), S( 0, 0), S(19, 37), S(24, 37), S(44, 97), S(35,106) }, // Minor on Defended
- { S(0, 0), S( 0, 0), S( 9, 14), S( 9, 14), S( 7, 14), S(24, 48) } }, // Rook on Defended
- { { S(0, 0), S( 0,32), S(33, 41), S(31, 50), S(41,100), S(35,104) }, // Minor on Weak
- { S(0, 0), S( 0,27), S(26, 57), S(26, 57), S(0 , 43), S(23, 51) } } // Rook on Weak
+ // Attacks on lesser pieces which are pawn defended are not considered.
+ const Score Threat[2][PIECE_TYPE_NB] = {
+ { S(0, 0), S(0, 32), S(25, 39), S(28, 44), S(42, 98), S(35,105) }, // Minor attacks
+ { S(0, 0), S(0, 27), S(26, 57), S(26, 57), S( 0, 30), S(23, 51) } // Rook attacks
};
// ThreatenedByPawn[PieceType] contains a penalty according to which piece
- // type is attacked by an enemy pawn.
+ // type is attacked by a pawn.
const Score ThreatenedByPawn[PIECE_TYPE_NB] = {
S(0, 0), S(0, 0), S(107, 138), S(84, 122), S(114, 203), S(121, 217)
};
const Bitboard TRank2BB = (Us == WHITE ? Rank2BB : Rank7BB);
const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
- enum { Defended, Weak };
enum { Minor, Rook };
Bitboard b, weak, defended, safeThreats;
// Non-pawn enemies defended by a pawn
defended = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & ei.attackedBy[Them][PAWN];
- // Add a bonus according to the kind of attacking pieces
- if (defended)
- {
- b = defended & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
- while (b)
- score += Threat[Defended][Minor][type_of(pos.piece_on(pop_lsb(&b)))];
-
- b = defended & ei.attackedBy[Us][ROOK];
- while (b)
- score += Threat[Defended][Rook][type_of(pos.piece_on(pop_lsb(&b)))];
- }
-
// Enemies not defended by a pawn and under our attack
weak = pos.pieces(Them)
& ~ei.attackedBy[Them][PAWN]
& ei.attackedBy[Us][ALL_PIECES];
// Add a bonus according to the kind of attacking pieces
- if (weak)
+ if (defended | weak)
{
- b = weak & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
+ b = (defended | weak) & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
while (b)
- score += Threat[Weak][Minor][type_of(pos.piece_on(pop_lsb(&b)))];
+ score += Threat[Minor][type_of(pos.piece_on(pop_lsb(&b)))];
- b = weak & ei.attackedBy[Us][ROOK];
+ b = (pos.pieces(Them, QUEEN) | weak) & ei.attackedBy[Us][ROOK];
while (b)
- score += Threat[Weak][Rook][type_of(pos.piece_on(pop_lsb(&b)))];
+ score += Threat[Rook ][type_of(pos.piece_on(pop_lsb(&b)))];
b = weak & ~ei.attackedBy[Them][ALL_PIECES];
if (b)
}
- // evaluate_initiative() computes the initiative correction value for the position, i.e.
- // second order bonus/malus based on the known attacking/defending status of the players.
+ // evaluate_initiative() computes the initiative correction value for the
+ // position, i.e. second order bonus/malus based on the known attacking/defending
+ // status of the players.
Score evaluate_initiative(const Position& pos, const EvalInfo& ei, const Score positional_score) {
- int pawns = pos.count<PAWN>(WHITE) + pos.count<PAWN>(BLACK);
- int king_separation = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
- int asymmetry = ei.pi->pawn_asymmetry();
+ int king_separation = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
+ int pawns = pos.count<PAWN>(WHITE) + pos.count<PAWN>(BLACK);
+ int asymmetry = ei.pi->pawn_asymmetry();
// Compute the initiative bonus for the attacking side
- int attacker_bonus = 8 * (pawns + asymmetry + king_separation) - 120;
+ int attacker_bonus = 8 * (pawns + asymmetry + king_separation) - 120;
- // Now apply the bonus: note that we find the attacking side by extracting the sign
+ // Now apply the bonus: note that we find the attacking side by extracting the sign
// of the endgame value of "positional_score", and that we carefully cap the bonus so
// that the endgame score with the correction will never be divided by more than two.
int eg = eg_value(positional_score);
- int value = ((eg > 0) - (eg < 0)) * std::max( attacker_bonus , -abs( eg / 2 ) );
+ int value = ((eg > 0) - (eg < 0)) * std::max(attacker_bonus, -abs(eg / 2));
- return make_score( 0 , value ) ;
+ return make_score(0, value);
}
} // namespace
// Evaluate space for both sides, only during opening
if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= 12222)
score += (evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei)) * Weights[Space];
-
+
// Evaluate initiative
score += evaluate_initiative(pos, ei, score);