X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fpawns.cpp;h=86c4b8ef2520eba9a1b64bf231ca93e5f2aadc16;hb=d980d7c0d4b2efe7abe26bdd094859f6d888ee60;hp=c85d4fd942b907cd6de1b0241c1bb49a763d57da;hpb=79d06d8840110713ca135ca53f2347a57c6494e2;p=stockfish diff --git a/src/pawns.cpp b/src/pawns.cpp index c85d4fd9..86c4b8ef 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -32,11 +32,11 @@ namespace { #define S(mg, eg) make_score(mg, eg) // Pawn penalties - constexpr Score Backward = S( 9, 24); - constexpr Score Doubled = S(11, 56); - constexpr Score Isolated = S( 5, 15); - constexpr Score WeakUnopposed = S( 13, 27); - constexpr Score Attacked2Unsupported = S( 0, 20); + constexpr Score Backward = S( 9, 24); + constexpr Score Doubled = S(11, 56); + constexpr Score Isolated = S( 5, 15); + constexpr Score WeakLever = S( 0, 56); + constexpr Score WeakUnopposed = S(13, 27); // Connected pawn bonus constexpr int Connected[RANK_NB] = { 0, 7, 8, 12, 29, 48, 86 }; @@ -70,25 +70,22 @@ namespace { constexpr Color Them = (Us == WHITE ? BLACK : WHITE); constexpr Direction Up = (Us == WHITE ? NORTH : SOUTH); - Bitboard b, neighbours, stoppers, doubled, support, phalanx; + Bitboard neighbours, stoppers, doubled, support, phalanx; Bitboard lever, leverPush; Square s; - bool opposed, backward; + bool opposed, backward, passed; Score score = SCORE_ZERO; const Square* pl = pos.squares(Us); Bitboard ourPawns = pos.pieces( Us, PAWN); Bitboard theirPawns = pos.pieces(Them, PAWN); + Bitboard doubleAttackThem = pawn_double_attacks_bb(theirPawns); + e->passedPawns[Us] = e->pawnAttacksSpan[Us] = 0; e->kingSquares[Us] = SQ_NONE; e->pawnAttacks[Us] = pawn_attacks_bb(ourPawns); - // Unsupported enemy pawns attacked twice by us - score += Attacked2Unsupported * popcount( theirPawns - & pawn_double_attacks_bb(ourPawns) - & ~pawn_attacks_bb(theirPawns)); - // Loop through all pawns of the current color and score each pawn while ((s = *pl++) != SQ_NONE) { @@ -108,27 +105,27 @@ namespace { phalanx = neighbours & rank_bb(s); 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. - backward = !(ourPawns & pawn_attack_span(Them, s + Up)) + // A pawn is backward when it is behind all pawns of the same color on + // the adjacent files and cannot safely advance. Phalanx and isolated + // pawns will be excluded when the pawn is scored. + backward = !(neighbours & forward_ranks_bb(Them, s)) && (stoppers & (leverPush | (s + Up))); - // Passed pawns will be properly scored in evaluation because we need - // full attack info to evaluate them. Include also not passed pawns - // which could become passed after one or two pawn pushes when are - // not attacked more times than defended. - if ( !(stoppers ^ lever) || - (!(stoppers ^ leverPush) && popcount(phalanx) >= popcount(leverPush))) + // A pawn is passed if one of the three following conditions is true: + // (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. + passed = !(stoppers ^ lever) + || ( !(stoppers ^ leverPush) + && popcount(phalanx) >= popcount(leverPush)) + || ( stoppers == square_bb(s + Up) && r >= RANK_5 + && (shift(support) & ~(theirPawns | doubleAttackThem))); + + // Passed pawns will be properly scored later in evaluation when we have + // full attack info. + if (passed) e->passedPawns[Us] |= s; - else if (stoppers == square_bb(s + Up) && r >= RANK_5) - { - b = shift(support) & ~theirPawns; - while (b) - if (!more_than_one(theirPawns & PawnAttacks[Us][pop_lsb(&b)])) - e->passedPawns[Us] |= s; - } - // Score this pawn if (support | phalanx) { @@ -137,6 +134,7 @@ namespace { score += make_score(v, v * (r - 2) / 4); } + else if (!neighbours) score -= Isolated + WeakUnopposed * int(!opposed); @@ -147,6 +145,11 @@ namespace { score -= Doubled; } + // Penalize our unsupported pawns attacked twice by enemy pawns + score -= WeakLever * popcount( ourPawns + & doubleAttackThem + & ~e->pawnAttacks[Us]); + return score; } @@ -181,13 +184,13 @@ Entry* probe(const Position& pos) { template void Entry::evaluate_shelter(const Position& pos, Square ksq, Score& shelter) { - constexpr Color Them = (Us == WHITE ? BLACK : WHITE); + constexpr Color Them = (Us == WHITE ? BLACK : WHITE); Bitboard b = pos.pieces(PAWN) & ~forward_ranks_bb(Them, ksq); Bitboard ourPawns = b & pos.pieces(Us); Bitboard theirPawns = b & pos.pieces(Them); - Value bonus[] = { Value(5), Value(5) }; + Score bonus = make_score(5, 5); File center = clamp(file_of(ksq), FILE_B, FILE_G); for (File f = File(center - 1); f <= File(center + 1); ++f) @@ -199,16 +202,16 @@ void Entry::evaluate_shelter(const Position& pos, Square ksq, Score& shelter) { Rank theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1; int d = std::min(f, ~f); - bonus[MG] += ShelterStrength[d][ourRank]; + bonus += make_score(ShelterStrength[d][ourRank], 0); if (ourRank && (ourRank == theirRank - 1)) - bonus[MG] -= 82 * (theirRank == RANK_3), bonus[EG] -= 82 * (theirRank == RANK_3); + bonus -= make_score(82 * (theirRank == RANK_3), 82 * (theirRank == RANK_3)); else - bonus[MG] -= UnblockedStorm[d][theirRank]; + bonus -= make_score(UnblockedStorm[d][theirRank], 0); } - if (bonus[MG] > mg_value(shelter)) - shelter = make_score(bonus[MG], bonus[EG]); + if (mg_value(bonus) > mg_value(shelter)) + shelter = bonus; }