X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=45c404712a200b949dbc0e3b515ebc81f4475bae;hp=8d6f812a6d56cf5607e06f51c903f96cad0fc01f;hb=4ae5a7b45a430aea5f4b21f9455b4db74ed1c44a;hpb=5f4d44fda053335ab20cb67c99323b8c182bf824 diff --git a/src/pawns.cpp b/src/pawns.cpp index 8d6f812a..45c40471 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -32,12 +32,14 @@ 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 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); // Connected pawn bonus - constexpr int Connected[RANK_NB] = { 0, 13, 17, 24, 59, 96, 171 }; + constexpr int Connected[RANK_NB] = { 0, 7, 8, 12, 29, 48, 86 }; // 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. @@ -51,11 +53,12 @@ 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. + // [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 @@ -77,16 +80,20 @@ namespace { Bitboard ourPawns = pos.pieces( Us, PAWN); Bitboard theirPawns = pos.pieces(Them, PAWN); - e->passedPawns[Us] = e->pawnAttacksSpan[Us] = e->weakUnopposed[Us] = 0; - e->kingSquares[Us] = SQ_NONE; - e->pawnAttacks[Us] = pawn_attacks_bb(ourPawns); + 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) { assert(pos.piece_on(s) == make_piece(Us, PAWN)); - File f = file_of(s); Rank r = relative_rank(Us, s); e->pawnAttacksSpan[Us] |= pawn_attack_span(Us, s); @@ -97,22 +104,22 @@ namespace { lever = theirPawns & PawnAttacks[Us][s]; leverPush = theirPawns & PawnAttacks[Us][s + Up]; doubled = ourPawns & (s - Up); - neighbours = ourPawns & adjacent_files_bb(f); + neighbours = ourPawns & adjacent_files_bb(s); 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 ^ leverPush) - && (support || !more_than_one(lever)) - && popcount(phalanx) >= popcount(leverPush)) + if ( !(stoppers ^ lever) || + (!(stoppers ^ leverPush) && popcount(phalanx) >= popcount(leverPush))) e->passedPawns[Us] |= s; else if (stoppers == square_bb(s + Up) && r >= RANK_5) @@ -126,15 +133,17 @@ namespace { // Score this pawn if (support | phalanx) { - int v = (phalanx ? 3 : 2) * Connected[r]; - v = 17 * popcount(support) + (v >> (opposed + 1)); + int v = Connected[r] * (phalanx ? 3 : 2) / (opposed ? 2 : 1) + + 17 * popcount(support); + score += make_score(v, v * (r - 2) / 4); } + else if (!neighbours) - score -= Isolated, e->weakUnopposed[Us] += !opposed; + score -= Isolated + WeakUnopposed * int(!opposed); else if (backward) - score -= Backward, e->weakUnopposed[Us] += !opposed; + score -= Backward + WeakUnopposed * int(!opposed); if (doubled && !support) score -= Doubled; @@ -174,38 +183,34 @@ 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, backmost_sq(Us, b)) : RANK_1; + Rank ourRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1; b = theirPawns & file_bb(f); 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; }