X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=src%2Fpawns.cpp;h=5df175b233c8092a1f2c41ba66f3f0d4c7de6c64;hb=7efc39d6833a0d999a7bf2f9b5629ceb246accd2;hp=5474850494cbb98036b2c307e172791b3ca3f099;hpb=d889bb47185e33012b45cab63359952247bc86e2;p=stockfish diff --git a/src/pawns.cpp b/src/pawns.cpp index 54748504..5df175b2 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 }; @@ -52,12 +52,13 @@ namespace { // 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. + // 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(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) } + { 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) } }; #undef S @@ -69,25 +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) { @@ -107,27 +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) { @@ -136,6 +134,7 @@ namespace { score += make_score(v, v * (r - 2) / 4); } + else if (!neighbours) score -= Isolated + WeakUnopposed * int(!opposed); @@ -146,6 +145,11 @@ namespace { score -= Doubled; } + // Penalize our unsupported pawns attacked twice by enemy pawns + score -= WeakLever * popcount( ourPawns + & doubleAttackThem + & ~e->pawnAttacks[Us]); + return score; } @@ -180,38 +184,34 @@ 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 Direction Down = (Us == WHITE ? SOUTH : NORTH); - constexpr Bitboard BlockSquares = (Rank1BB | Rank2BB | Rank7BB | Rank8BB) - & (FileABB | FileHBB); + 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[] = { (shift(theirPawns) & BlockSquares & ksq) ? Value(374) : Value(5), - VALUE_ZERO }; + 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) { b = ourPawns & file_bb(f); - Rank ourRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1; + int ourRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : 0; b = theirPawns & file_bb(f); - Rank theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1; + int theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : 0; 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; } @@ -234,7 +234,7 @@ Score Entry::do_king_safety(const Position& pos) { else while (pawns) minPawnDist = std::min(minPawnDist, distance(ksq, pop_lsb(&pawns))); - Score shelter = make_score(-VALUE_INFINITE, VALUE_ZERO); + Score shelter = make_score(-VALUE_INFINITE, 0); evaluate_shelter(pos, ksq, shelter); // If we can castle use the bonus after the castling if it is bigger @@ -244,7 +244,7 @@ Score Entry::do_king_safety(const Position& pos) { if (pos.can_castle(Us | QUEEN_SIDE)) evaluate_shelter(pos, relative_square(Us, SQ_C1), shelter); - return shelter - make_score(VALUE_ZERO, 16 * minPawnDist); + return shelter - make_score(0, 16 * minPawnDist); } // Explicit template instantiation