Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
- Copyright (C) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+ Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
template<Color Us> void initialize();
template<Color Us> Score evaluate_king();
template<Color Us> Score evaluate_threats();
+ int king_distance(Color c, Square s);
template<Color Us> Score evaluate_passed_pawns();
template<Color Us> Score evaluate_space();
template<Color Us, PieceType Pt> Score evaluate_pieces();
// which piece type attacks which one. Attacks on lesser pieces which are
// pawn-defended are not considered.
const Score ThreatByMinor[PIECE_TYPE_NB] = {
- S(0, 0), S(0, 33), S(45, 43), S(46, 47), S(72, 107), S(48, 118)
+ S(0, 0), S(0, 31), S(39, 42), S(57, 44), S(68, 112), S(47, 120)
};
const Score ThreatByRook[PIECE_TYPE_NB] = {
- S(0, 0), S(0, 25), S(40, 62), S(40, 59), S(0, 34), S(35, 48)
+ S(0, 0), S(0, 24), S(38, 71), S(38, 61), S(0, 38), S(36, 38)
};
// ThreatByKing[on one/on many] contains bonuses for king attacks on
// pawns or pieces which are not pawn-defended.
- const Score ThreatByKing[] = { S(3, 62), S(9, 138) };
+ const Score ThreatByKing[] = { S(3, 65), S(9, 145) };
// Passed[mg/eg][Rank] contains midgame and endgame bonuses for passed pawns.
// We don't use a Score because we process the two components independently.
const Value Passed[][RANK_NB] = {
- { V(5), V( 5), V(31), V(73), V(166), V(252) },
- { V(7), V(14), V(38), V(73), V(166), V(252) }
+ { V(0), V(5), V( 5), V(32), V(70), V(172), V(217) },
+ { V(0), V(7), V(13), V(42), V(70), V(170), V(269) }
};
// PassedFile[File] contains a bonus according to the file of a passed pawn
S(-20,-12), S( 1, -8), S( 2, 10), S( 9, 10)
};
+ // Rank factor applied on some bonus for passed pawn on rank 4 or beyond
+ const int RankFactor[RANK_NB] = {0, 0, 0, 2, 7, 12, 19};
+
// KingProtector[PieceType-2] contains a bonus according to distance from king
const Score KingProtector[] = { S(-3, -5), S(-4, -3), S(-3, 0), S(-1, 1) };
const Score WeakQueen = S( 50, 10);
const Score CloseEnemies = S( 7, 0);
const Score PawnlessFlank = S( 20, 80);
- const Score ThreatByHangingPawn = S( 71, 61);
- const Score ThreatBySafePawn = S(192,175);
+ const Score ThreatBySafePawn = S(175,168);
const Score ThreatByRank = S( 16, 3);
- const Score Hanging = S( 48, 27);
+ const Score Hanging = S( 52, 30);
const Score WeakUnopposedPawn = S( 5, 25);
- const Score ThreatByPawnPush = S( 38, 22);
- const Score ThreatByAttackOnQueen = S( 38, 22);
- const Score HinderPassedPawn = S( 7, 0);
+ const Score ThreatByPawnPush = S( 47, 26);
+ const Score ThreatByAttackOnQueen = S( 42, 21);
+ const Score HinderPassedPawn = S( 8, 1);
const Score TrappedBishopA1H1 = S( 50, 50);
#undef S
while ((s = *pl++) != SQ_NONE)
{
// Find attacked squares, including x-ray attacks for bishops and rooks
- b = Pt == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(Us, QUEEN))
- : Pt == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN))
+ b = Pt == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(QUEEN))
+ : Pt == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(QUEEN) ^ pos.pieces(Us, ROOK))
: pos.attacks_from<Pt>(s);
if (pos.pinned_pieces(Us) & s)
// Penalty when trapped by the king, even more if the king cannot castle
else if (mob <= 3)
{
- Square ksq = pos.square<KING>(Us);
+ File kf = file_of(pos.square<KING>(Us));
- if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
- && !pe->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq)))
+ if ((kf < FILE_E) == (file_of(s) < kf))
score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.can_castle(Us));
}
}
- 9 * mg_value(score) / 8
+ 40;
- // Transform the kingDanger units into a Score, and substract it from the evaluation
+ // Transform the kingDanger units into a Score, and subtract it from the evaluation
if (kingDanger > 0)
+ {
+ int mobilityDanger = mg_value(mobility[Them] - mobility[Us]);
+ kingDanger = std::max(0, kingDanger + mobilityDanger);
score -= make_score(kingDanger * kingDanger / 4096, kingDanger / 16);
+ }
}
// King tropism: firstly, find squares that opponent attacks in our king flank
safeThreats = (shift<Right>(b) | shift<Left>(b)) & weak;
score += ThreatBySafePawn * popcount(safeThreats);
-
- if (weak ^ safeThreats)
- score += ThreatByHangingPawn;
}
// Squares strongly protected by the opponent, either because they attack the
return score;
}
+ // king_distance() returns an estimate of the distance that the king
+ // of the given color has to run to reach square s.
+ template<Tracing T>
+ int Evaluation<T>::king_distance(Color c, Square s) {
+ return std::min(distance(pos.square<KING>(c), s), 5);
+ }
// evaluate_passed_pawns() evaluates the passed pawns and candidate passed
// pawns of the given color.
bb = forward_file_bb(Us, s) & (attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
score -= HinderPassedPawn * popcount(bb);
- int r = relative_rank(Us, s) - RANK_2;
- int rr = r * (r - 1);
+ int r = relative_rank(Us, s);
+ int rr = RankFactor[r];
Value mbonus = Passed[MG][r], ebonus = Passed[EG][r];
Square blockSq = s + Up;
// Adjust bonus based on the king's proximity
- ebonus += distance(pos.square<KING>(Them), blockSq) * 5 * rr
- - distance(pos.square<KING>( Us), blockSq) * 2 * rr;
+ ebonus += (king_distance(Them, blockSq) * 5 - king_distance(Us, blockSq) * 2) * rr;
// If blockSq is not the queening square then consider also a second push
- if (relative_rank(Us, blockSq) != RANK_8)
- ebonus -= distance(pos.square<KING>(Us), blockSq + Up) * rr;
+ if (r != RANK_7)
+ ebonus -= king_distance(Us, blockSq + Up) * rr;
// If the pawn is free to advance, then increase the bonus
if (pos.empty(blockSq))
// 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 = !unsafeSquares ? 18 : !(unsafeSquares & blockSq) ? 8 : 0;
+ int k = !unsafeSquares ? 20 : !(unsafeSquares & blockSq) ? 9 : 0;
// If the path to the queen is fully defended, assign a big bonus.
// Otherwise assign a smaller bonus if the block square is defended.
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
-Score Eval::Contempt = SCORE_ZERO;
+std::atomic<Score> Eval::Contempt;
/// evaluate() is the evaluator for the outer world. It returns a static evaluation
/// of the position from the point of view of the side to move.
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();
+ Eval::Contempt = SCORE_ZERO;
+
+ Value v = Eval::Tempo + Evaluation<TRACE>(pos).value();
+
v = pos.side_to_move() == WHITE ? v : -v; // White's point of view
std::stringstream ss;
projects / stockfish / blobdiff