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
// Pawn penalties
constexpr Score Backward = S( 9, 24);
- constexpr Score BlockedStorm = S(82, 82);
constexpr Score Doubled = S(11, 56);
constexpr Score Isolated = S( 5, 15);
constexpr Score WeakLever = S( 0, 56);
constexpr Score WeakUnopposed = S(13, 27);
+ constexpr Score BlockedStorm[RANK_NB] = {S( 0, 0), S( 0, 0), S( 76, 78), S(-10, 15), S(-7, 10), S(-4, 6), S(-1, 2)};
+
// Connected pawn bonus
constexpr int Connected[RANK_NB] = { 0, 7, 8, 12, 29, 48, 86 };
// is behind our king. Note that UnblockedStorm[0][1-2] accommodate opponent pawn
// on edge, likely blocked by our king.
constexpr Value UnblockedStorm[int(FILE_NB) / 2][RANK_NB] = {
- { V( 89), V(-285), V(-185), 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) }
+ { V( 85), V(-289), V(-166), V(97), V(50), V( 45), V( 50) },
+ { V( 46), V( -25), V( 122), V(45), V(37), V(-10), V( 20) },
+ { V( -6), V( 51), V( 168), V(34), V(-2), V(-22), V(-14) },
+ { V(-15), V( -11), V( 101), V( 4), V(11), V(-15), V(-29) }
};
#undef S
template<Color Us>
Score evaluate(const Position& pos, Pawns::Entry* e) {
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
- constexpr Direction Up = (Us == WHITE ? NORTH : SOUTH);
+ constexpr Color Them = ~Us;
+ constexpr Direction Up = pawn_push(Us);
Bitboard neighbours, stoppers, support, phalanx, opposed;
Bitboard lever, leverPush, blocked;
e->passedPawns[Us] = 0;
e->kingSquares[Us] = SQ_NONE;
e->pawnAttacks[Us] = e->pawnAttacksSpan[Us] = pawn_attacks_bb<Us>(ourPawns);
+ e->blockedCount += popcount(shift<Up>(ourPawns) & (theirPawns | doubleAttackThem));
// Loop through all pawns of the current color and score each pawn
while ((s = *pl++) != SQ_NONE)
// A pawn is backward when it is behind all pawns of the same color on
// the adjacent files and cannot safely advance.
backward = !(neighbours & forward_ranks_bb(Them, s + Up))
- && (stoppers & (leverPush | blocked));
+ && (leverPush | blocked);
// Compute additional span if pawn is not backward nor blocked
if (!backward && !blocked)
// (a) there is no stoppers except some levers
// (b) the only stoppers are the leverPush, but we outnumber them
// (c) there is only one front stopper which can be levered.
+ // (Refined in Evaluation::passed)
passed = !(stoppers ^ lever)
|| ( !(stoppers ^ leverPush)
&& popcount(phalanx) >= popcount(leverPush))
|| ( stoppers == blocked && r >= RANK_5
&& (shift<Up>(support) & ~(theirPawns | doubleAttackThem)));
+ passed &= !(forward_file_bb(Us, s) & ourPawns);
+
// Passed pawns will be properly scored later in evaluation when we have
// full attack info.
if (passed)
// Score this pawn
if (support | phalanx)
{
- int v = Connected[r] * (2 + bool(phalanx) - bool(opposed))
+ int v = Connected[r] * (4 + 2 * bool(phalanx) - 2 * bool(opposed) - bool(blocked)) / 2
+ 21 * popcount(support);
score += make_score(v, v * (r - 2) / 4);
}
else if (!neighbours)
+ {
score -= Isolated
+ WeakUnopposed * !opposed;
+ if ( (ourPawns & forward_file_bb(Them, s))
+ && popcount(opposed) == 1
+ && !(theirPawns & adjacent_files_bb(s)))
+ score -= Doubled;
+ }
+
else if (backward)
score -= Backward
+ WeakUnopposed * !opposed;
return e;
e->key = key;
+ e->blockedCount = 0;
e->scores[WHITE] = evaluate<WHITE>(pos, e);
e->scores[BLACK] = evaluate<BLACK>(pos, e);
template<Color Us>
Score Entry::evaluate_shelter(const Position& pos, Square ksq) {
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Color Them = ~Us;
Bitboard b = pos.pieces(PAWN) & ~forward_ranks_bb(Them, ksq);
- Bitboard ourPawns = b & pos.pieces(Us);
+ Bitboard ourPawns = b & pos.pieces(Us) & ~pawnAttacks[Them];
Bitboard theirPawns = b & pos.pieces(Them);
Score bonus = make_score(5, 5);
- File center = clamp(file_of(ksq), FILE_B, FILE_G);
+ File center = Utility::clamp(file_of(ksq), FILE_B, FILE_G);
for (File f = File(center - 1); f <= File(center + 1); ++f)
{
b = ourPawns & file_bb(f);
b = theirPawns & file_bb(f);
int theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : 0;
- File d = map_to_queenside(f);
+ int d = edge_distance(f);
bonus += make_score(ShelterStrength[d][ourRank], 0);
if (ourRank && (ourRank == theirRank - 1))
- bonus -= BlockedStorm * int(theirRank == RANK_3);
+ bonus -= BlockedStorm[theirRank];
else
bonus -= make_score(UnblockedStorm[d][theirRank], 0);
}
// In endgame we like to bring our king near our closest pawn
Bitboard pawns = pos.pieces(Us, PAWN);
- int minPawnDist = pawns ? 8 : 0;
+ int minPawnDist = 6;
if (pawns & PseudoAttacks[KING][ksq])
minPawnDist = 1;
projects / stockfish / blobdiff