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) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+ Copyright (C) 2015-2019 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
#define V Value
#define S(mg, eg) make_score(mg, eg)
- // Isolated pawn penalty
- constexpr Score Isolated = S(13, 16);
-
- // Backward pawn penalty
- constexpr Score Backward = S(17, 11);
+ // Pawn penalties
+ constexpr Score Backward = S( 9, 24);
+ constexpr Score Doubled = S(11, 56);
+ constexpr Score Isolated = S( 5, 15);
// Connected pawn bonus by opposed, phalanx, #support and rank
Score Connected[2][2][3][RANK_NB];
- // Doubled pawn penalty
- constexpr Score Doubled = S(13, 40);
-
// Strength of pawn shelter for our king by [distance from edge][rank].
// RANK_1 = 0 is used for files where we have no pawn, or pawn is behind our king.
constexpr Value ShelterStrength[int(FILE_NB) / 2][RANK_NB] = {
- { V( 7), V(76), V(84), V( 38), V( 7), V( 30), V(-19) },
- { V(-3), V(93), V(52), V(-17), V(12), V(-22), V(-35) },
- { V(-6), V(83), V(25), V(-24), V(15), V( 22), V(-39) },
- { V(11), V(83), V(19), V( 8), V(18), V(-21), V(-30) }
+ { V( -6), V( 81), V( 93), V( 58), V( 39), V( 18), V( 25) },
+ { V(-43), V( 61), V( 35), V(-49), V(-29), V(-11), V( -63) },
+ { V(-10), V( 75), V( 23), V( -2), V( 32), V( 3), V( -45) },
+ { V(-39), V(-13), V(-29), V(-52), V(-48), V(-67), V(-166) }
};
- // Danger of enemy pawns moving toward our king by [type][distance from edge][rank].
- // For the unblocked case, RANK_1 = 0 is used when opponent has no pawn on the
- // given file, or their pawn is behind our king.
- constexpr Value StormDanger[][4][RANK_NB] = {
- { { V(25), V( 79), V(107), V( 51), V( 27) }, // UnBlocked
- { V(15), V( 45), V(131), V( 8), V( 25) },
- { V( 0), V( 42), V(118), V( 56), V( 27) },
- { V( 3), V( 54), V(110), V( 55), V( 26) } },
- { { V( 0), V( 0), V( 37), V( 5), V(-48) }, // BlockedByPawn
- { V( 0), V( 0), V( 68), V(-12), V( 13) },
- { V( 0), V( 0), V(111), V(-25), V( -3) },
- { V( 0), V( 0), V(108), V( 14), V( 21) } }
+ // Danger of enemy pawns moving toward our king by [distance from edge][rank].
+ // RANK_1 = 0 is used for files where the enemy has no pawn, or their pawn
+ // is behind our king.
+ constexpr Value UnblockedStorm[int(FILE_NB) / 2][RANK_NB] = {
+ { V( 89), V(107), V(123), V(93), V(57), V( 45), V( 51) },
+ { V( 44), V(-18), V(123), V(46), V(39), V( -7), V( 23) },
+ { V( 4), V( 52), V(162), V(37), V( 7), V(-14), V( -2) },
+ { V(-10), V(-14), V( 90), V(15), V( 2), V( -7), V(-16) }
};
#undef S
constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
constexpr Direction Up = (Us == WHITE ? NORTH : SOUTH);
- Bitboard b, neighbours, stoppers, doubled, supported, phalanx;
+ Bitboard b, neighbours, stoppers, doubled, support, phalanx;
Bitboard lever, leverPush;
Square s;
bool opposed, backward;
doubled = ourPawns & (s - Up);
neighbours = ourPawns & adjacent_files_bb(f);
phalanx = neighbours & rank_bb(s);
- supported = neighbours & rank_bb(s - Up);
+ support = neighbours & rank_bb(s - Up);
// A pawn is backward when it is behind all pawns of the same color
// on the adjacent files and cannot be safely advanced.
// which could become passed after one or two pawn pushes when are
// not attacked more times than defended.
if ( !(stoppers ^ lever ^ leverPush)
- && !(ourPawns & forward_file_bb(Us, s))
- && popcount(supported) >= popcount(lever) - 1
+ && popcount(support) >= popcount(lever) - 1
&& popcount(phalanx) >= popcount(leverPush))
e->passedPawns[Us] |= s;
else if ( stoppers == SquareBB[s + Up]
&& relative_rank(Us, s) >= RANK_5)
{
- b = shift<Up>(supported) & ~theirPawns;
+ b = shift<Up>(support) & ~theirPawns;
while (b)
if (!more_than_one(theirPawns & PawnAttacks[Us][pop_lsb(&b)]))
e->passedPawns[Us] |= s;
}
// Score this pawn
- if (supported | phalanx)
- score += Connected[opposed][bool(phalanx)][popcount(supported)][relative_rank(Us, s)];
+ if (support | phalanx)
+ score += Connected[opposed][bool(phalanx)][popcount(support)][relative_rank(Us, s)];
else if (!neighbours)
score -= Isolated, e->weakUnopposed[Us] += !opposed;
else if (backward)
score -= Backward, e->weakUnopposed[Us] += !opposed;
- if (doubled && !supported)
+ if (doubled && !support)
score -= Doubled;
}
template<Color Us>
Value Entry::evaluate_shelter(const Position& pos, Square ksq) {
- enum { UnBlocked, BlockedByPawn };
constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
constexpr Direction Down = (Us == WHITE ? SOUTH : NORTH);
constexpr Bitboard BlockRanks = (Us == WHITE ? Rank1BB | Rank2BB : Rank8BB | Rank7BB);
- Bitboard b = pos.pieces(PAWN) & (forward_ranks_bb(Us, ksq) | rank_bb(ksq));
+ Bitboard b = pos.pieces(PAWN) & ~forward_ranks_bb(Them, ksq);
Bitboard ourPawns = b & pos.pieces(Us);
Bitboard theirPawns = b & pos.pieces(Them);
- Value safety = (ourPawns & file_bb(ksq)) ? Value(5) : Value(-5);
-
- if (shift<Down>(theirPawns) & (FileABB | FileHBB) & BlockRanks & ksq)
- safety += Value(374);
+ Value safety = (shift<Down>(theirPawns) & (FileABB | FileHBB) & BlockRanks & ksq) ?
+ Value(374) : Value(5);
File center = std::max(FILE_B, std::min(FILE_G, file_of(ksq)));
for (File f = File(center - 1); f <= File(center + 1); ++f)
{
b = ourPawns & file_bb(f);
- int ourRank = b ? relative_rank(Us, backmost_sq(Us, b)) : 0;
+ Rank ourRank = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1;
b = theirPawns & file_bb(f);
- int theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : 0;
+ Rank theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1;
int d = std::min(f, ~f);
-
safety += ShelterStrength[d][ourRank];
- if (ourRank || theirRank)
- safety -= StormDanger[ourRank && (ourRank == theirRank - 1) ? BlockedByPawn : UnBlocked][d][theirRank];
+ safety -= (ourRank && (ourRank == theirRank - 1)) ? 66 * (theirRank == RANK_3)
+ : UnblockedStorm[d][theirRank];
}
return safety;
/// when king square changes, which is about 20% of total king_safety() calls.
template<Color Us>
-Score Entry::do_king_safety(const Position& pos, Square ksq) {
+Score Entry::do_king_safety(const Position& pos) {
+ Square ksq = pos.square<KING>(Us);
kingSquares[Us] = ksq;
- castlingRights[Us] = pos.can_castle(Us);
+ castlingRights[Us] = pos.castling_rights(Us);
int minKingPawnDistance = 0;
Bitboard pawns = pos.pieces(Us, PAWN);
if (pawns)
- while (!(DistanceRingBB[ksq][minKingPawnDistance++] & pawns)) {}
+ while (!(DistanceRingBB[ksq][++minKingPawnDistance] & pawns)) {}
Value bonus = evaluate_shelter<Us>(pos, ksq);
// If we can castle use the bonus after the castling if it is bigger
- if (pos.can_castle(MakeCastling<Us, KING_SIDE>::right))
+ if (pos.can_castle(Us | KING_SIDE))
bonus = std::max(bonus, evaluate_shelter<Us>(pos, relative_square(Us, SQ_G1)));
- if (pos.can_castle(MakeCastling<Us, QUEEN_SIDE>::right))
+ if (pos.can_castle(Us | QUEEN_SIDE))
bonus = std::max(bonus, evaluate_shelter<Us>(pos, relative_square(Us, SQ_C1)));
return make_score(bonus, -16 * minKingPawnDistance);
}
// Explicit template instantiation
-template Score Entry::do_king_safety<WHITE>(const Position& pos, Square ksq);
-template Score Entry::do_king_safety<BLACK>(const Position& pos, Square ksq);
+template Score Entry::do_king_safety<WHITE>(const Position& pos);
+template Score Entry::do_king_safety<BLACK>(const Position& pos);
} // namespace Pawns
projects / stockfish / blobdiff