Score mobility[COLOR_NB] = { SCORE_ZERO, SCORE_ZERO };
// attackedBy[color][piece type] is a bitboard representing all squares
- // attacked by a given color and piece type (can be also ALL_PIECES).
+ // attacked by a given color and piece type. Special "piece types" which are
+ // also calculated are QUEEN_DIAGONAL and ALL_PIECES.
Bitboard attackedBy[COLOR_NB][PIECE_TYPE_NB];
// attackedBy2[color] are the squares attacked by 2 pieces of a given color,
const Score RookOnPawn = S( 8, 24);
const Score TrappedRook = S( 92, 0);
const Score WeakQueen = S( 50, 10);
- const Score OtherCheck = S( 10, 10);
const Score CloseEnemies = S( 7, 0);
const Score PawnlessFlank = S( 20, 80);
const Score ThreatByHangingPawn = S( 71, 61);
const int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 78, 56, 45, 11 };
// Penalties for enemy's safe checks
- const int QueenCheck = 780;
- const int RookCheck = 880;
- const int BishopCheck = 435;
- const int KnightCheck = 790;
+ const int QueenSafeCheck = 780;
+ const int RookSafeCheck = 880;
+ const int BishopSafeCheck = 435;
+ const int KnightSafeCheck = 790;
// Threshold for lazy and space evaluation
const Value LazyThreshold = Value(1500);
Score Evaluation<T>::evaluate_king() {
const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Direction Up = (Us == WHITE ? NORTH : SOUTH);
const Bitboard Camp = (Us == WHITE ? AllSquares ^ Rank6BB ^ Rank7BB ^ Rank8BB
: AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB);
const Square ksq = pos.square<KING>(Us);
- Bitboard weak, b, b1, b2, safe, other;
- int kingDanger;
+ Bitboard weak, b, b1, b2, safe, unsafeChecks;
// King shelter and enemy pawns storm
Score score = pe->king_safety<Us>(pos, ksq);
& ~attackedBy2[Us]
& (attackedBy[Us][KING] | attackedBy[Us][QUEEN] | ~attackedBy[Us][ALL_PIECES]);
- // Initialize the 'kingDanger' variable, which will be transformed
- // later into a king danger score. The initial value is based on the
- // number and types of the enemy's attacking pieces, the number of
- // attacked and weak squares around our king, the absence of queen and
- // the quality of the pawn shelter (current 'score' value).
- kingDanger = kingAttackersCount[Them] * kingAttackersWeight[Them]
- + 102 * kingAdjacentZoneAttacksCount[Them]
- + 191 * popcount(kingRing[Us] & weak)
- + 143 * bool(pos.pinned_pieces(Us))
- - 848 * !pos.count<QUEEN>(Them)
- - 9 * mg_value(score) / 8
- + 40;
+ int kingDanger = unsafeChecks = 0;
// Analyse the safe enemy's checks which are possible on next move
safe = ~pos.pieces(Them);
safe &= ~attackedBy[Us][ALL_PIECES] | (weak & attackedBy2[Them]);
- b1 = pos.attacks_from< ROOK>(ksq);
- b2 = pos.attacks_from<BISHOP>(ksq);
+ b1 = attacks_bb<ROOK >(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN));
+ b2 = attacks_bb<BISHOP>(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN));
// Enemy queen safe checks
if ((b1 | b2) & attackedBy[Them][QUEEN] & safe & ~attackedBy[Us][QUEEN])
- kingDanger += QueenCheck;
-
- // Some other potential checks are also analysed, even from squares
- // currently occupied by the opponent own pieces, as long as the square
- // is not attacked by our pawns, and is not occupied by a blocked pawn.
- other = ~( attackedBy[Us][PAWN]
- | (pos.pieces(Them, PAWN) & shift<Up>(pos.pieces(PAWN))));
+ kingDanger += QueenSafeCheck;
- // Enemy rooks safe and other checks
- if (b1 & attackedBy[Them][ROOK] & safe)
- kingDanger += RookCheck;
+ b1 &= attackedBy[Them][ROOK];
+ b2 &= attackedBy[Them][BISHOP];
- else if (b1 & attackedBy[Them][ROOK] & other)
- score -= OtherCheck;
+ // Enemy rooks checks
+ if (b1 & safe)
+ kingDanger += RookSafeCheck;
+ else
+ unsafeChecks |= b1;
- // Enemy bishops safe and other checks
- if (b2 & attackedBy[Them][BISHOP] & safe)
- kingDanger += BishopCheck;
+ // Enemy bishops checks
+ if (b2 & safe)
+ kingDanger += BishopSafeCheck;
+ else
+ unsafeChecks |= b2;
- else if (b2 & attackedBy[Them][BISHOP] & other)
- score -= OtherCheck;
-
- // Enemy knights safe and other checks
+ // Enemy knights checks
b = pos.attacks_from<KNIGHT>(ksq) & attackedBy[Them][KNIGHT];
if (b & safe)
- kingDanger += KnightCheck;
-
- else if (b & other)
- score -= OtherCheck;
+ kingDanger += KnightSafeCheck;
+ else
+ unsafeChecks |= b;
+
+ // Unsafe or occupied checking squares will also be considered, as long as
+ // the square is in the attacker's mobility area.
+ unsafeChecks &= mobilityArea[Them];
+
+ kingDanger += kingAttackersCount[Them] * kingAttackersWeight[Them]
+ + 102 * kingAdjacentZoneAttacksCount[Them]
+ + 191 * popcount(kingRing[Us] & weak)
+ + 143 * popcount(pos.pinned_pieces(Us) | unsafeChecks)
+ - 848 * !pos.count<QUEEN>(Them)
+ - 9 * mg_value(score) / 8
+ + 40;
// Transform the kingDanger units into a Score, and substract it from the evaluation
if (kingDanger > 0)
Trace::add(TOTAL, score);
}
- return (pos.side_to_move() == WHITE ? v : -v) + Eval::Tempo; // Side to move point of view
+ return pos.side_to_move() == WHITE ? v : -v; // Side to move point of view
}
} // namespace
Value Eval::evaluate(const Position& pos)
{
- return Evaluation<>(pos).value();
+ return Evaluation<>(pos).value() + Eval::Tempo;
}
/// trace() is like evaluate(), but instead of returning a value, it returns
std::memset(scores, 0, sizeof(scores));
- Value v = Evaluation<TRACE>(pos).value();
+ Value v = Evaluation<TRACE>(pos).value() + Eval::Tempo;
v = pos.side_to_move() == WHITE ? v : -v; // White's point of view
std::stringstream ss;
projects / stockfish / blobdiff