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) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+ Copyright (C) 2015-2020 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
// 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), // Knights
+ { 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(-48,-59), S(-20,-23), S( 16, -3), S( 26, 13), S( 38, 24), S( 51, 42), // Bishops
+ { 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(-58,-76), S(-27,-18), S(-15, 28), S(-10, 55), S( -5, 69), S( -2, 82), // Rooks
+ { S(-58,-76), S(-27,-18), S(-15, 28), S(-10, 55), S( -5, 69), S( -2, 82), // Rook
S( 9,112), S( 16,118), S( 30,132), S( 29,142), S( 32,155), S( 38,165),
S( 46,166), S( 48,169), S( 58,171) },
- { S(-39,-36), S(-21,-15), S( 3, 8), S( 3, 18), S( 14, 34), S( 22, 54), // Queens
+ { S(-39,-36), S(-21,-15), S( 3, 8), S( 3, 18), S( 14, 34), S( 22, 54), // Queen
S( 28, 61), S( 41, 73), S( 43, 79), S( 48, 92), S( 56, 94), S( 60,104),
S( 60,113), S( 66,120), S( 67,123), S( 70,126), S( 71,133), S( 73,136),
S( 79,140), S( 88,143), S( 88,148), S( 99,166), S(102,170), S(102,175),
// which piece type attacks which one. Attacks on lesser pieces which are
// pawn-defended are not considered.
constexpr Score ThreatByMinor[PIECE_TYPE_NB] = {
- S(0, 0), S(6, 32), S(59, 41), S(79, 56), S(90, 119), S(79, 161)
+ S(0, 0), S(5, 32), S(57, 41), S(77, 56), S(88, 119), S(79, 161)
};
constexpr Score ThreatByRook[PIECE_TYPE_NB] = {
- S(0, 0), S(3, 44), S(38, 71), S(38, 61), S(0, 38), S(51, 38)
+ S(0, 0), S(2, 44), S(36, 71), S(36, 61), S(0, 38), S(51, 38)
};
// PassedRank[Rank] contains a bonus according to the rank of a passed pawn
};
// Assorted bonuses and penalties
- constexpr Score BishopPawns = S( 3, 7);
- constexpr Score CorneredBishop = S( 50, 50);
- constexpr Score FlankAttacks = S( 8, 0);
- constexpr Score Hanging = S( 69, 36);
- constexpr Score KingProtector = S( 7, 8);
- constexpr Score KnightOnQueen = S( 16, 12);
- constexpr Score LongDiagonalBishop = S( 45, 0);
- constexpr Score MinorBehindPawn = S( 18, 3);
- constexpr Score Outpost = S( 30, 21);
- constexpr Score PassedFile = S( 11, 8);
- constexpr Score PawnlessFlank = S( 17, 95);
- constexpr Score RestrictedPiece = S( 7, 7);
- constexpr Score ReachableOutpost = S( 32, 10);
- constexpr Score RookOnQueenFile = S( 7, 6);
- constexpr Score SliderOnQueen = S( 59, 18);
- constexpr Score ThreatByKing = S( 24, 89);
- constexpr Score ThreatByPawnPush = S( 48, 39);
- constexpr Score ThreatBySafePawn = S(173, 94);
- constexpr Score TrappedRook = S( 47, 4);
- constexpr Score WeakQueen = S( 49, 15);
+ constexpr Score BishopPawns = S( 3, 7);
+ constexpr Score CorneredBishop = S( 50, 50);
+ constexpr Score FlankAttacks = S( 8, 0);
+ constexpr Score Hanging = S( 69, 36);
+ constexpr Score KingProtector = S( 7, 8);
+ constexpr Score KnightOnQueen = S( 16, 12);
+ constexpr Score LongDiagonalBishop = S( 45, 0);
+ constexpr Score MinorBehindPawn = S( 18, 3);
+ constexpr Score Outpost = S( 30, 21);
+ constexpr Score PassedFile = S( 11, 8);
+ constexpr Score PawnlessFlank = S( 17, 95);
+ constexpr Score RestrictedPiece = S( 7, 7);
+ constexpr Score RookOnQueenFile = S( 7, 6);
+ constexpr Score SliderOnQueen = S( 59, 18);
+ constexpr Score ThreatByKing = S( 24, 89);
+ constexpr Score ThreatByPawnPush = S( 48, 39);
+ constexpr Score ThreatBySafePawn = S(173, 94);
+ constexpr Score TrappedRook = S( 52, 10);
+ constexpr Score WeakQueen = S( 49, 15);
+ constexpr Score WeakQueenProtection = S( 14, 0);
#undef S
template<Tracing T> template<Color Us>
void Evaluation<T>::initialize() {
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Color Them = ~Us;
constexpr Direction Up = pawn_push(Us);
constexpr Direction Down = -Up;
constexpr Bitboard LowRanks = (Us == WHITE ? Rank2BB | Rank3BB : Rank7BB | Rank6BB);
// Find our pawns that are blocked or on the first two ranks
Bitboard b = pos.pieces(Us, PAWN) & (shift<Down>(pos.pieces()) | LowRanks);
- // Squares occupied by those pawns, by our king or queen or controlled by
- // enemy pawns are excluded from the mobility area.
- mobilityArea[Us] = ~(b | pos.pieces(Us, KING, QUEEN) | pe->pawn_attacks(Them));
+ // Squares occupied by those pawns, by our king or queen, by blockers to attacks on our king
+ // or controlled by enemy pawns are excluded from the mobility area.
+ mobilityArea[Us] = ~(b | pos.pieces(Us, KING, QUEEN) | pos.blockers_for_king(Us) | pe->pawn_attacks(Them));
// Initialize attackedBy[] for king and pawns
attackedBy[Us][KING] = pos.attacks_from<KING>(ksq);
attackedBy2[Us] = dblAttackByPawn | (attackedBy[Us][KING] & attackedBy[Us][PAWN]);
// Init our king safety tables
- Square s = make_square(clamp(file_of(ksq), FILE_B, FILE_G),
- clamp(rank_of(ksq), RANK_2, RANK_7));
+ Square s = make_square(Utility::clamp(file_of(ksq), FILE_B, FILE_G),
+ Utility::clamp(rank_of(ksq), RANK_2, RANK_7));
kingRing[Us] = PseudoAttacks[KING][s] | s;
kingAttackersCount[Them] = popcount(kingRing[Us] & pe->pawn_attacks(Them));
template<Tracing T> template<Color Us, PieceType Pt>
Score Evaluation<T>::pieces() {
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Color Them = ~Us;
constexpr Direction Down = -pawn_push(Us);
constexpr Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB
: Rank5BB | Rank4BB | Rank3BB);
score += Outpost * (Pt == KNIGHT ? 2 : 1);
else if (Pt == KNIGHT && bb & b & ~pos.pieces(Us))
- score += ReachableOutpost;
+ score += Outpost;
- // Knight and Bishop bonus for being right behind a pawn
+ // Bonus for a knight or bishop shielded by pawn
if (shift<Down>(pos.pieces(PAWN)) & s)
score += MinorBehindPawn;
// Penalty if the piece is far from the king
- score -= KingProtector * distance(s, pos.square<KING>(Us));
+ score -= KingProtector * distance(pos.square<KING>(Us), s);
if (Pt == BISHOP)
{
// Penalty according to number of pawns on the same color square as the
- // bishop, bigger when the center files are blocked with pawns.
+ // 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());
score -= BishopPawns * pos.pawns_on_same_color_squares(Us, s)
- * (1 + popcount(blocked & CenterFiles));
+ * (!(attackedBy[Us][PAWN] & s) + popcount(blocked & CenterFiles));
// Bonus for bishop on a long diagonal which can "see" both center squares
if (more_than_one(attacks_bb<BISHOP>(s, pos.pieces(PAWN)) & Center))
score += LongDiagonalBishop;
- }
- // An important Chess960 pattern: A cornered bishop blocked by a friendly
- // pawn diagonally in front of it is a very serious problem, especially
- // when that pawn is also blocked.
- if ( Pt == BISHOP
- && pos.is_chess960()
- && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
- {
- Direction d = pawn_push(Us) + (file_of(s) == FILE_A ? EAST : WEST);
- if (pos.piece_on(s + d) == make_piece(Us, PAWN))
- score -= !pos.empty(s + d + pawn_push(Us)) ? CorneredBishop * 4
- : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? CorneredBishop * 2
- : CorneredBishop;
+ // An important Chess960 pattern: a cornered bishop blocked by a friendly
+ // pawn diagonally in front of it is a very serious problem, especially
+ // when that pawn is also blocked.
+ if ( pos.is_chess960()
+ && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
+ {
+ Direction d = pawn_push(Us) + (file_of(s) == FILE_A ? EAST : WEST);
+ if (pos.piece_on(s + d) == make_piece(Us, PAWN))
+ score -= !pos.empty(s + d + pawn_push(Us)) ? CorneredBishop * 4
+ : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? CorneredBishop * 2
+ : CorneredBishop;
+ }
}
}
template<Tracing T> template<Color Us>
Score Evaluation<T>::king() const {
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Color Them = ~Us;
constexpr Bitboard Camp = (Us == WHITE ? AllSquares ^ Rank6BB ^ Rank7BB ^ Rank8BB
: AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB);
template<Tracing T> template<Color Us>
Score Evaluation<T>::threats() const {
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Color Them = ~Us;
constexpr Direction Up = pawn_push(Us);
constexpr Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
b = ~attackedBy[Them][ALL_PIECES]
| (nonPawnEnemies & attackedBy2[Us]);
score += Hanging * popcount(weak & b);
+
+ // Additional bonus if weak piece is only protected by a queen
+ score += WeakQueenProtection * popcount(weak & attackedBy[Them][QUEEN]);
}
// Bonus for restricting their piece moves
b = attackedBy[Them][ALL_PIECES]
& ~stronglyProtected
& attackedBy[Us][ALL_PIECES];
-
score += RestrictedPiece * popcount(b);
// Protected or unattacked squares
template<Tracing T> template<Color Us>
Score Evaluation<T>::passed() const {
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Color Them = ~Us;
constexpr Direction Up = pawn_push(Us);
auto king_proximity = [&](Color c, Square s) {
Square blockSq = s + Up;
// Adjust bonus based on the king's proximity
- bonus += make_score(0, ( king_proximity(Them, blockSq) * 5
- - king_proximity(Us, blockSq) * 2) * w);
+ bonus += make_score(0, ( (king_proximity(Them, blockSq) * 19) / 4
+ - king_proximity(Us, blockSq) * 2) * w);
// If blockSq is not the queening square then consider also a second push
if (r != RANK_7)
} // r > RANK_3
// 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) & (s + Up)))
+ // pawn push to become passed.
+ if (!pos.pawn_passed(Us, s + Up))
bonus = bonus / 2;
- score += bonus - PassedFile * map_to_queenside(file_of(s));
+ score += bonus - PassedFile * edge_distance(file_of(s));
}
if (T)
if (pos.non_pawn_material() < SpaceThreshold)
return SCORE_ZERO;
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Color Them = ~Us;
constexpr Direction Down = -pawn_push(Us);
constexpr Bitboard SpaceMask =
Us == WHITE ? CenterFiles & (Rank2BB | Rank3BB | Rank4BB)
template<Tracing T>
Score Evaluation<T>::initiative(Score score) const {
- Value mg = mg_value(score);
- Value eg = eg_value(score);
-
int outflanking = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK))
- distance<Rank>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
bool pawnsOnBothFlanks = (pos.pieces(PAWN) & QueenSide)
&& (pos.pieces(PAWN) & KingSide);
- bool almostUnwinnable = !pe->passed_count()
- && outflanking < 0
+ bool almostUnwinnable = outflanking < 0
&& !pawnsOnBothFlanks;
+ bool infiltration = rank_of(pos.square<KING>(WHITE)) > RANK_4
+ || rank_of(pos.square<KING>(BLACK)) < RANK_5;
+
// Compute the initiative bonus for the attacking side
int complexity = 9 * pe->passed_count()
+ 11 * pos.count<PAWN>()
+ 9 * outflanking
+ 21 * pawnsOnBothFlanks
+ + 24 * infiltration
+ 51 * !pos.non_pawn_material()
- 43 * almostUnwinnable
- - 95 ;
+ -110 ;
+
+ Value mg = mg_value(score);
+ Value eg = eg_value(score);
// Now apply the bonus: note that we find the attacking side by extracting the
// sign of the midgame or endgame values, and that we carefully cap the bonus
Trace::add(TOTAL, score);
}
- return (pos.side_to_move() == WHITE ? v : -v) // Side to move point of view
- + Eval::Tempo;
+ return (pos.side_to_move() == WHITE ? v : -v) + Tempo; // Side to move point of view
}
} // namespace
std::string Eval::trace(const Position& pos) {
+ if (pos.checkers())
+ return "Total evaluation: none (in check)";
+
std::memset(scores, 0, sizeof(scores));
pos.this_thread()->contempt = SCORE_ZERO; // Reset any dynamic contempt
projects / stockfish / blobdiff