X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=721df3729af56c4e8dc7f87a70a438ca74b90a47;hp=86745924bcfe2f308f04a1f9290a7b22d399f27b;hb=820c5c25b649d6bdd51bed14a16efdc11719b588;hpb=29b5842da8d5477c0aea924cfd364c9e619456a2 diff --git a/src/pawns.cpp b/src/pawns.cpp index 86745924..721df372 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -2,7 +2,7 @@ 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) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2015-2018 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 @@ -31,58 +31,52 @@ namespace { #define V Value #define S(mg, eg) make_score(mg, eg) - // Isolated pawn penalty by opposed flag and file - const Score Isolated[2][FILE_NB] = { - { S(31, 36), S(45, 41), S(50, 41), S(50, 41), - S(50, 41), S(50, 41), S(45, 41), S(31, 36) }, - { S(21, 24), S(30, 28), S(33, 28), S(33, 28), - S(33, 28), S(33, 28), S(30, 28), S(21, 24) } }; - - // Backward pawn penalty by opposed flag - const Score Backward[2] = { S(56, 33), S(41, 19) }; - - // Unsupported pawn penalty for pawns which are neither isolated or backward, - // by number of pawns it supports [less than 2 / exactly 2]. - const Score Unsupported[2] = { S(17, 8), S(21, 12) }; - - // Connected pawn bonus by opposed, phalanx, twice supported and rank - Score Connected[2][2][2][RANK_NB]; - - // Doubled pawn penalty by file - const Score Doubled[FILE_NB] = { - S(11, 34), S(17, 38), S(19, 38), S(19, 38), - S(19, 38), S(19, 38), S(17, 38), S(11, 34) }; - - // Lever bonus by rank - const Score Lever[RANK_NB] = { - S( 0, 0), S( 0, 0), S(0, 0), S(0, 0), - S(17, 16), S(33, 32), S(0, 0), S(0, 0) }; - - // Weakness of our pawn shelter in front of the king by [distance from edge][rank] - const Value ShelterWeakness[][RANK_NB] = { - { V( 97), V(21), V(26), V(51), V(87), V( 89), V( 99) }, - { V(120), V( 0), V(28), V(76), V(88), V(103), V(104) }, - { V(101), V( 7), V(54), V(78), V(77), V( 92), V(101) }, - { V( 80), V(11), V(44), V(68), V(87), V( 90), V(119) } }; - - // Danger of enemy pawns moving toward our king by [type][distance from edge][rank] + // Isolated pawn penalty + const Score Isolated = S(13, 18); + + // Backward pawn penalty + const Score Backward = S(24, 12); + + // Connected pawn bonus by opposed, phalanx, #support and rank + Score Connected[2][2][3][RANK_NB]; + + // Doubled pawn penalty + const Score Doubled = S(18, 38); + + // Weakness of our pawn shelter in front of the king by [isKingFile][distance from edge][rank]. + // RANK_1 = 0 is used for files where we have no pawns or our pawn is behind our king. + const Value ShelterWeakness[][int(FILE_NB) / 2][RANK_NB] = { + { { V( 98), V(20), V(11), V(42), V( 83), V( 84), V(101) }, // Not On King file + { V(103), V( 8), V(33), V(86), V( 87), V(105), V(113) }, + { V(100), V( 2), V(65), V(95), V( 59), V( 89), V(115) }, + { V( 72), V( 6), V(52), V(74), V( 83), V( 84), V(112) } }, + { { V(105), V(19), V( 3), V(27), V( 85), V( 93), V( 84) }, // On King file + { V(121), V( 7), V(33), V(95), V(112), V( 86), V( 72) }, + { V(121), V(26), V(65), V(90), V( 65), V( 76), V(117) }, + { V( 79), V( 0), V(45), V(65), V( 94), V( 92), V(105) } } + }; + + // Danger of enemy pawns moving toward our king by [type][distance from edge][rank]. + // For the unopposed and unblocked cases, RANK_1 = 0 is used when opponent has + // no pawn on the given file, or their pawn is behind our king. const Value StormDanger[][4][RANK_NB] = { - { { V( 0), V( 67), V( 134), V(38), V(32) }, - { V( 0), V( 57), V( 139), V(37), V(22) }, - { V( 0), V( 43), V( 115), V(43), V(27) }, - { V( 0), V( 68), V( 124), V(57), V(32) } }, - { { V(20), V( 43), V( 100), V(56), V(20) }, - { V(23), V( 20), V( 98), V(40), V(15) }, - { V(23), V( 39), V( 103), V(36), V(18) }, - { V(28), V( 19), V( 108), V(42), V(26) } }, - { { V( 0), V( 0), V( 75), V(14), V( 2) }, - { V( 0), V( 0), V( 150), V(30), V( 4) }, - { V( 0), V( 0), V( 160), V(22), V( 5) }, - { V( 0), V( 0), V( 166), V(24), V(13) } }, - { { V( 0), V(-283), V(-281), V(57), V(31) }, - { V( 0), V( 58), V( 141), V(39), V(18) }, - { V( 0), V( 65), V( 142), V(48), V(32) }, - { V( 0), V( 60), V( 126), V(51), V(19) } } }; + { { V( 0), V(-290), V(-274), V(57), V(41) }, // BlockedByKing + { V( 0), V( 60), V( 144), V(39), V(13) }, + { V( 0), V( 65), V( 141), V(41), V(34) }, + { V( 0), V( 53), V( 127), V(56), V(14) } }, + { { V( 4), V( 73), V( 132), V(46), V(31) }, // Unopposed + { V( 1), V( 64), V( 143), V(26), V(13) }, + { V( 1), V( 47), V( 110), V(44), V(24) }, + { V( 0), V( 72), V( 127), V(50), V(31) } }, + { { V( 0), V( 0), V( 79), V(23), V( 1) }, // BlockedByPawn + { V( 0), V( 0), V( 148), V(27), V( 2) }, + { V( 0), V( 0), V( 161), V(16), V( 1) }, + { V( 0), V( 0), V( 171), V(22), V(15) } }, + { { V(22), V( 45), V( 104), V(62), V( 6) }, // Unblocked + { V(31), V( 30), V( 99), V(39), V(19) }, + { V(23), V( 29), V( 96), V(41), V(15) }, + { V(21), V( 23), V( 116), V(41), V(15) } } + }; // Max bonus for king safety. Corresponds to start position with all the pawns // in front of the king and no enemy pawn on the horizon. @@ -94,25 +88,23 @@ namespace { template Score evaluate(const Position& pos, Pawns::Entry* e) { - const Color Them = (Us == WHITE ? BLACK : WHITE); - const Square Up = (Us == WHITE ? DELTA_N : DELTA_S); - const Square Right = (Us == WHITE ? DELTA_NE : DELTA_SW); - const Square Left = (Us == WHITE ? DELTA_NW : DELTA_SE); + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Direction Up = (Us == WHITE ? NORTH : SOUTH); Bitboard b, neighbours, stoppers, doubled, supported, phalanx; + Bitboard lever, leverPush; Square s; - bool opposed, lever, connected, backward; + bool opposed, backward; Score score = SCORE_ZERO; const Square* pl = pos.squares(Us); - const Bitboard* pawnAttacksBB = StepAttacksBB[make_piece(Us, PAWN)]; - Bitboard ourPawns = pos.pieces(Us , PAWN); + Bitboard ourPawns = pos.pieces( Us, PAWN); Bitboard theirPawns = pos.pieces(Them, PAWN); - e->passedPawns[Us] = e->pawnAttacksSpan[Us] = 0; - e->kingSquares[Us] = SQ_NONE; + e->passedPawns[Us] = e->pawnAttacksSpan[Us] = e->weakUnopposed[Us] = 0; e->semiopenFiles[Us] = 0xFF; - e->pawnAttacks[Us] = shift_bb(ourPawns) | shift_bb(ourPawns); + e->kingSquares[Us] = SQ_NONE; + e->pawnAttacks[Us] = pos.pawn_attacks(ourPawns); e->pawnsOnSquares[Us][BLACK] = popcount(ourPawns & DarkSquares); e->pawnsOnSquares[Us][WHITE] = pos.count(Us) - e->pawnsOnSquares[Us][BLACK]; @@ -123,18 +115,18 @@ namespace { File f = file_of(s); - e->semiopenFiles[Us] &= ~(1 << f); + e->semiopenFiles[Us] &= ~(1 << f); e->pawnAttacksSpan[Us] |= pawn_attack_span(Us, s); // Flag the pawn - opposed = theirPawns & forward_bb(Us, s); + opposed = theirPawns & forward_file_bb(Us, s); stoppers = theirPawns & passed_pawn_mask(Us, s); - lever = theirPawns & pawnAttacksBB[s]; - doubled = ourPawns & forward_bb(Us, s); + lever = theirPawns & PawnAttacks[Us][s]; + leverPush = theirPawns & PawnAttacks[Us][s + Up]; + doubled = ourPawns & (s - Up); neighbours = ourPawns & adjacent_files_bb(f); phalanx = neighbours & rank_bb(s); supported = neighbours & rank_bb(s - Up); - connected = supported | phalanx; // A pawn is backward when it is behind all pawns of the same color on the // adjacent files and cannot be safely advanced. @@ -148,40 +140,44 @@ namespace { // The pawn is backward when it cannot safely progress to that rank: // either there is a stopper in the way on this rank, or there is a // stopper on adjacent file which controls the way to that rank. - backward = (b | shift_bb(b & adjacent_files_bb(f))) & stoppers; - - assert(!backward || !(pawn_attack_span(Them, s + Up) & neighbours)); + backward = (b | shift(b & adjacent_files_bb(f))) & stoppers; + + assert(!(backward && (forward_ranks_bb(Them, s + Up) & neighbours))); } // Passed pawns will be properly scored in evaluation because we need - // full attack info to evaluate them. Only the frontmost passed - // pawn on each file is considered a true passed pawn. - if (!(stoppers | doubled)) + // 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) + && !(ourPawns & forward_file_bb(Us, s)) + && popcount(supported) >= popcount(lever) + && popcount(phalanx) >= popcount(leverPush)) e->passedPawns[Us] |= s; - // Score this pawn - if (!neighbours) - score -= Isolated[opposed][f]; - - else if (backward) - score -= Backward[opposed]; + else if ( stoppers == SquareBB[s + Up] + && relative_rank(Us, s) >= RANK_5) + { + b = shift(supported) & ~theirPawns; + while (b) + if (!more_than_one(theirPawns & PawnAttacks[Us][pop_lsb(&b)])) + e->passedPawns[Us] |= s; + } - else if (!supported) - score -= Unsupported[more_than_one(neighbours & pawnAttacksBB[s])]; + // Score this pawn + if (supported | phalanx) + score += Connected[opposed][bool(phalanx)][popcount(supported)][relative_rank(Us, s)]; - if (connected) - score += Connected[opposed][!!phalanx][more_than_one(supported)][relative_rank(Us, s)]; + else if (!neighbours) + score -= Isolated, e->weakUnopposed[Us] += !opposed; - if (doubled) - score -= Doubled[f] / distance(s, frontmost_sq(Us, doubled)); + else if (backward) + score -= Backward, e->weakUnopposed[Us] += !opposed; - if (lever) - score += Lever[relative_rank(Us, s)]; + if (doubled && !supported) + score -= Doubled; } - b = e->semiopenFiles[Us] ^ 0xFF; - e->pawnSpan[Us] = b ? int(msb(b) - lsb(b)) : 0; - return score; } @@ -193,18 +189,19 @@ namespace Pawns { /// hard-coded tables, when makes sense, we prefer to calculate them with a formula /// to reduce independent parameters and to allow easier tuning and better insight. -void init() -{ - static const int Seed[RANK_NB] = { 0, 8, 19, 13, 71, 94, 169, 324 }; +void init() { + + static const int Seed[RANK_NB] = { 0, 13, 24, 18, 76, 100, 175, 330 }; for (int opposed = 0; opposed <= 1; ++opposed) for (int phalanx = 0; phalanx <= 1; ++phalanx) - for (int apex = 0; apex <= 1; ++apex) + for (int support = 0; support <= 2; ++support) for (Rank r = RANK_2; r < RANK_8; ++r) { - int v = (Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0)) >> opposed; - v += (apex ? v / 2 : 0); - Connected[opposed][phalanx][apex][r] = make_score(v, v * 5 / 8); + int v = 17 * support; + v += (Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0)) >> opposed; + + Connected[opposed][phalanx][support][r] = make_score(v, v * (r - 2) / 4); } } @@ -223,42 +220,46 @@ Entry* probe(const Position& pos) { return e; e->key = key; - e->score = evaluate(pos, e) - evaluate(pos, e); + e->scores[WHITE] = evaluate(pos, e); + e->scores[BLACK] = evaluate(pos, e); e->asymmetry = popcount(e->semiopenFiles[WHITE] ^ e->semiopenFiles[BLACK]); + e->openFiles = popcount(e->semiopenFiles[WHITE] & e->semiopenFiles[BLACK]); + return e; } /// Entry::shelter_storm() calculates shelter and storm penalties for the file -/// the king is on, as well as the two adjacent files. +/// the king is on, as well as the two closest files. template Value Entry::shelter_storm(const Position& pos, Square ksq) { const Color Them = (Us == WHITE ? BLACK : WHITE); - enum { NoFriendlyPawn, Unblocked, BlockedByPawn, BlockedByKing }; + enum { BlockedByKing, Unopposed, BlockedByPawn, Unblocked }; - Bitboard b = pos.pieces(PAWN) & (in_front_bb(Us, rank_of(ksq)) | rank_bb(ksq)); + Bitboard b = pos.pieces(PAWN) & (forward_ranks_bb(Us, ksq) | rank_bb(ksq)); Bitboard ourPawns = b & pos.pieces(Us); Bitboard theirPawns = b & pos.pieces(Them); Value safety = MaxSafetyBonus; File center = std::max(FILE_B, std::min(FILE_G, file_of(ksq))); - for (File f = center - File(1); f <= center + File(1); ++f) + for (File f = File(center - 1); f <= File(center + 1); ++f) { b = ourPawns & file_bb(f); Rank rkUs = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1; - b = theirPawns & file_bb(f); + b = theirPawns & file_bb(f); Rank rkThem = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1; - safety -= ShelterWeakness[std::min(f, FILE_H - f)][rkUs] + int d = std::min(f, ~f); + safety -= ShelterWeakness[f == file_of(ksq)][d][rkUs] + StormDanger [f == file_of(ksq) && rkThem == relative_rank(Us, ksq) + 1 ? BlockedByKing : - rkUs == RANK_1 ? NoFriendlyPawn : + rkUs == RANK_1 ? Unopposed : rkThem == rkUs + 1 ? BlockedByPawn : Unblocked] - [std::min(f, FILE_H - f)][rkThem]; + [d][rkThem]; } return safety;