X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=0846344223137f93a2372c737b6a553609e8c5a4;hp=91f8ed752004cb7a48760f71fb0c4d0679617545;hb=0ddf84870ad9f7fb4309e992e1e5eae968577958;hpb=ccdb634b7722a300707b9348ac30ae2c4152da8a diff --git a/src/pawns.cpp b/src/pawns.cpp index 91f8ed75..08463442 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -1,7 +1,7 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2009 Marco Costalba + Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, 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 @@ -38,96 +38,42 @@ namespace { /// Constants and variables - // Doubled pawn penalty by file, middle game - const Value DoubledPawnMidgamePenalty[8] = { - Value(13), Value(20), Value(23), Value(23), - Value(23), Value(23), Value(20), Value(13) + #define S(mg, eg) make_score(mg, eg) + + // Doubled pawn penalty by opposed flag and file + const Score DoubledPawnPenalty[2][8] = { + { S(13, 43), S(20, 48), S(23, 48), S(23, 48), + S(23, 48), S(23, 48), S(20, 48), S(13, 43) }, + { S(13, 43), S(20, 48), S(23, 48), S(23, 48), + S(23, 48), S(23, 48), S(20, 48), S(13, 43) }}; + + // Isolated pawn penalty by opposed flag and file + const Score IsolatedPawnPenalty[2][8] = { + { S(37, 45), S(54, 52), S(60, 52), S(60, 52), + S(60, 52), S(60, 52), S(54, 52), S(37, 45) }, + { S(25, 30), S(36, 35), S(40, 35), S(40, 35), + S(40, 35), S(40, 35), S(36, 35), S(25, 30) }}; + + // Backward pawn penalty by opposed flag and file + const Score BackwardPawnPenalty[2][8] = { + { S(30, 42), S(43, 46), S(49, 46), S(49, 46), + S(49, 46), S(49, 46), S(43, 46), S(30, 42) }, + { S(20, 28), S(29, 31), S(33, 31), S(33, 31), + S(33, 31), S(33, 31), S(29, 31), S(20, 28) }}; + + // Pawn chain membership bonus by file + const Score ChainBonus[8] = { + S(11,-1), S(13,-1), S(13,-1), S(14,-1), + S(14,-1), S(13,-1), S(13,-1), S(11,-1) }; - // Doubled pawn penalty by file, endgame - const Value DoubledPawnEndgamePenalty[8] = { - Value(43), Value(48), Value(48), Value(48), - Value(48), Value(48), Value(48), Value(43) + // Candidate passed pawn bonus by rank + const Score CandidateBonus[8] = { + S( 0, 0), S( 6, 13), S(6,13), S(14,29), + S(34,68), S(83,166), S(0, 0), S( 0, 0) }; - // Isolated pawn penalty by file, middle game - const Value IsolatedPawnMidgamePenalty[8] = { - Value(25), Value(36), Value(40), Value(40), - Value(40), Value(40), Value(36), Value(25) - }; - - // Isolated pawn penalty by file, endgame - const Value IsolatedPawnEndgamePenalty[8] = { - Value(30), Value(35), Value(35), Value(35), - Value(35), Value(35), Value(35), Value(30) - }; - - // Backward pawn penalty by file, middle game - const Value BackwardPawnMidgamePenalty[8] = { - Value(20), Value(29), Value(33), Value(33), - Value(33), Value(33), Value(29), Value(20) - }; - - // Backward pawn penalty by file, endgame - const Value BackwardPawnEndgamePenalty[8] = { - Value(28), Value(31), Value(31), Value(31), - Value(31), Value(31), Value(31), Value(28) - }; - - // Pawn chain membership bonus by file, middle game - const Value ChainMidgameBonus[8] = { - Value(11), Value(13), Value(13), Value(14), - Value(14), Value(13), Value(13), Value(11) - }; - - // Pawn chain membership bonus by file, endgame - const Value ChainEndgameBonus[8] = { - Value(-1), Value(-1), Value(-1), Value(-1), - Value(-1), Value(-1), Value(-1), Value(-1) - }; - - // Candidate passed pawn bonus by rank, middle game - const Value CandidateMidgameBonus[8] = { - Value( 0), Value( 6), Value(6), Value(14), - Value(34), Value(83), Value(0), Value( 0) - }; - - // Candidate passed pawn bonus by rank, endgame - const Value CandidateEndgameBonus[8] = { - Value( 0), Value( 13), Value(13), Value(29), - Value(68), Value(166), Value( 0), Value( 0) - }; - - // Pawn storm tables for positions with opposite castling - const int QStormTable[64] = { - 0, 0, 0, 0, 0, 0, 0, 0, - -22,-22,-22,-14,-6, 0, 0, 0, - -6,-10,-10,-10,-6, 0, 0, 0, - 4, 12, 16, 12, 4, 0, 0, 0, - 16, 23, 23, 16, 0, 0, 0, 0, - 23, 31, 31, 23, 0, 0, 0, 0, - 23, 31, 31, 23, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0 - }; - - const int KStormTable[64] = { - 0, 0, 0, 0, 0, 0, 0, 0, - 0, 0, 0,-10,-19,-28,-33,-33, - 0, 0, 0,-10,-15,-19,-24,-24, - 0, 0, 0, 0, 1, 1, 1, 1, - 0, 0, 0, 0, 1, 10, 19, 19, - 0, 0, 0, 0, 1, 19, 31, 27, - 0, 0, 0, 0, 0, 22, 31, 22, - 0, 0, 0, 0, 0, 0, 0, 0 - }; - - // Pawn storm open file bonuses by file - const int16_t KStormOpenFileBonus[8] = { 31, 31, 18, 0, 0, 0, 0, 0 }; - const int16_t QStormOpenFileBonus[8] = { 0, 0, 0, 0, 0, 26, 42, 26 }; - - // Pawn storm lever bonuses by file - const int StormLeverBonus[8] = { -8, -8, -13, 0, 0, -13, -8, -8 }; - + #undef S } @@ -135,50 +81,18 @@ namespace { //// Functions //// -/// Constructor - -PawnInfoTable::PawnInfoTable(unsigned numOfEntries) { - - size = numOfEntries; - entries = new PawnInfo[size]; - if (!entries) - { - std::cerr << "Failed to allocate " << (numOfEntries * sizeof(PawnInfo)) - << " bytes for pawn hash table." << std::endl; - Application::exit_with_failure(); - } -} - - -/// Destructor - -PawnInfoTable::~PawnInfoTable() { - delete [] entries; -} - - -/// PawnInfo::clear() resets to zero the PawnInfo entry. Note that -/// kingSquares[] is initialized to SQ_NONE instead. - -void PawnInfo::clear() { - - memset(this, 0, sizeof(PawnInfo)); - kingSquares[WHITE] = kingSquares[BLACK] = SQ_NONE; -} - /// PawnInfoTable::get_pawn_info() takes a position object as input, computes -/// a PawnInfo object, and returns a pointer to it. The result is also -/// stored in a hash table, so we don't have to recompute everything when -/// the same pawn structure occurs again. +/// a PawnInfo object, and returns a pointer to it. The result is also stored +/// in a hash table, so we don't have to recompute everything when the same +/// pawn structure occurs again. -PawnInfo* PawnInfoTable::get_pawn_info(const Position& pos) { +PawnInfo* PawnInfoTable::get_pawn_info(const Position& pos) const { assert(pos.is_ok()); Key key = pos.get_pawn_key(); - int index = int(key & (size - 1)); - PawnInfo* pi = entries + index; + PawnInfo* pi = find(key); // If pi->key matches the position's pawn hash key, it means that we // have analysed this pawn structure before, and we can simply return @@ -187,21 +101,20 @@ PawnInfo* PawnInfoTable::get_pawn_info(const Position& pos) { return pi; // Clear the PawnInfo object, and set the key - pi->clear(); + memset(pi, 0, sizeof(PawnInfo)); + pi->halfOpenFiles[WHITE] = pi->halfOpenFiles[BLACK] = 0xFF; + pi->kingSquares[WHITE] = pi->kingSquares[BLACK] = SQ_NONE; pi->key = key; // Calculate pawn attacks - Bitboard whitePawns = pos.pieces(PAWN, WHITE); - Bitboard blackPawns = pos.pieces(PAWN, BLACK); - pi->pawnAttacks[WHITE] = ((whitePawns << 9) & ~FileABB) | ((whitePawns << 7) & ~FileHBB); - pi->pawnAttacks[BLACK] = ((blackPawns >> 7) & ~FileABB) | ((blackPawns >> 9) & ~FileHBB); + Bitboard wPawns = pos.pieces(PAWN, WHITE); + Bitboard bPawns = pos.pieces(PAWN, BLACK); + pi->pawnAttacks[WHITE] = ((wPawns << 9) & ~FileABB) | ((wPawns << 7) & ~FileHBB); + pi->pawnAttacks[BLACK] = ((bPawns >> 7) & ~FileABB) | ((bPawns >> 9) & ~FileHBB); // Evaluate pawns for both colors - Values whiteValues = evaluate_pawns(pos, whitePawns, blackPawns, pi); - Values blackValues = evaluate_pawns(pos, blackPawns, whitePawns, pi); - - pi->mgValue = int16_t(whiteValues.first - blackValues.first); - pi->egValue = int16_t(whiteValues.second - blackValues.second); + pi->value = evaluate_pawns(pos, wPawns, bPawns, pi) + - evaluate_pawns(pos, bPawns, wPawns, pi); return pi; } @@ -209,126 +122,56 @@ PawnInfo* PawnInfoTable::get_pawn_info(const Position& pos) { /// PawnInfoTable::evaluate_pawns() evaluates each pawn of the given color template -PawnInfoTable::Values PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns, - Bitboard theirPawns, PawnInfo* pi) { +Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns, + Bitboard theirPawns, PawnInfo* pi) const { + Bitboard b; Square s; File f; Rank r; - bool passed, isolated, doubled, chain, backward, candidate; - int bonus; - Value mgValue = Value(0); - Value egValue = Value(0); - Bitboard pawns = ourPawns; - - // Initialize pawn storm scores by giving bonuses for open files - for (File f = FILE_A; f <= FILE_H; f++) - if (!(ourPawns & file_bb(f))) - { - pi->ksStormValue[Us] += KStormOpenFileBonus[f]; - pi->qsStormValue[Us] += QStormOpenFileBonus[f]; - pi->halfOpenFiles[Us] |= (1 << f); - } + bool passed, isolated, doubled, opposed, chain, backward, candidate; + Score value = SCORE_ZERO; + const BitCountType Max15 = CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15; + const Square* ptr = pos.piece_list_begin(Us, PAWN); // Loop through all pawns of the current color and score each pawn - while (pawns) + while ((s = *ptr++) != SQ_NONE) { - s = pop_1st_bit(&pawns); + assert(pos.piece_on(s) == piece_of_color_and_type(Us, PAWN)); + f = square_file(s); r = square_rank(s); - assert(pos.piece_on(s) == piece_of_color_and_type(Us, PAWN)); + // This file cannot be half open + pi->halfOpenFiles[Us] &= ~(1 << f); - // Passed, isolated or doubled pawn? - passed = Position::pawn_is_passed(theirPawns, Us, s); - isolated = Position::pawn_is_isolated(ourPawns, s); - doubled = Position::pawn_is_doubled(ourPawns, Us, s); + // Our rank plus previous one. Used for chain detection. + b = rank_bb(r) | rank_bb(Us == WHITE ? r - Rank(1) : r + Rank(1)); - // We calculate kingside and queenside pawn storm - // scores for both colors. These are used when evaluating - // middle game positions with opposite side castling. - // - // Each pawn is given a base score given by a piece square table - // (KStormTable[] or QStormTable[]). Pawns which seem to have good - // chances of creating an open file by exchanging itself against an - // enemy pawn on an adjacent file gets an additional bonus. - - // Kingside pawn storms - bonus = KStormTable[relative_square(Us, s)]; - if (f >= FILE_F) - { - Bitboard b = outpost_mask(Us, s) & theirPawns & (FileFBB | FileGBB | FileHBB); - while (b) - { - Square s2 = pop_1st_bit(&b); - if (!(theirPawns & neighboring_files_bb(s2) & rank_bb(s2))) - { - // The enemy pawn has no pawn beside itself, which makes it - // particularly vulnerable. Big bonus, especially against a - // weakness on the rook file. - if (square_file(s2) == FILE_H) - bonus += 4*StormLeverBonus[f] - 8*square_distance(s, s2); - else - bonus += 2*StormLeverBonus[f] - 4*square_distance(s, s2); - } else - // There is at least one enemy pawn beside the enemy pawn we look - // at, which means that the pawn has somewhat better chances of - // defending itself by advancing. Smaller bonus. - bonus += StormLeverBonus[f] - 2*square_distance(s, s2); - } - } - pi->ksStormValue[Us] += bonus; - - // Queenside pawn storms - bonus = QStormTable[relative_square(Us, s)]; - if (f <= FILE_C) - { - Bitboard b = outpost_mask(Us, s) & theirPawns & (FileABB | FileBBB | FileCBB); - while (b) - { - Square s2 = pop_1st_bit(&b); - if (!(theirPawns & neighboring_files_bb(s2) & rank_bb(s2))) - { - // The enemy pawn has no pawn beside itself, which makes it - // particularly vulnerable. Big bonus, especially against a - // weakness on the rook file. - if (square_file(s2) == FILE_A) - bonus += 4*StormLeverBonus[f] - 16*square_distance(s, s2); - else - bonus += 2*StormLeverBonus[f] - 8*square_distance(s, s2); - } else - // There is at least one enemy pawn beside the enemy pawn we look - // at, which means that the pawn has somewhat better chances of - // defending itself by advancing. Smaller bonus. - bonus += StormLeverBonus[f] - 4*square_distance(s, s2); - } - } - pi->qsStormValue[Us] += bonus; - - // Member of a pawn chain (but not the backward one)? We could speed up - // the test a little by introducing an array of masks indexed by color - // and square for doing the test, but because everything is hashed, - // it probably won't make any noticable difference. - chain = ourPawns - & neighboring_files_bb(f) - & (rank_bb(r) | rank_bb(r - (Us == WHITE ? 1 : -1))); + // Passed, isolated, doubled or member of a pawn + // chain (but not the backward one) ? + passed = !(theirPawns & passed_pawn_mask(Us, s)); + doubled = ourPawns & squares_in_front_of(Us, s); + opposed = theirPawns & squares_in_front_of(Us, s); + isolated = !(ourPawns & neighboring_files_bb(f)); + chain = ourPawns & neighboring_files_bb(f) & b; // Test for backward pawn // + backward = false; + // If the pawn is passed, isolated, or member of a pawn chain // it cannot be backward. If can capture an enemy pawn or if // there are friendly pawns behind on neighboring files it cannot // be backward either. - if ( (passed | isolated | chain) - || (ourPawns & behind_bb(Us, r) & neighboring_files_bb(f)) - || (pos.attacks_from(s, Us) & theirPawns)) - backward = false; - else + if ( !(passed | isolated | chain) + && !(ourPawns & attack_span_mask(opposite_color(Us), s)) + && !(pos.attacks_from(s, Us) & theirPawns)) { // We now know that there are no friendly pawns beside or behind this // pawn on neighboring files. We now check whether the pawn is // backward by looking in the forward direction on the neighboring // files, and seeing whether we meet a friendly or an enemy pawn first. - Bitboard b = pos.attacks_from(s, Us); + b = pos.attacks_from(s, Us); // Note that we are sure to find something because pawn is not passed // nor isolated, so loop is potentially infinite, but it isn't. @@ -340,77 +183,34 @@ PawnInfoTable::Values PawnInfoTable::evaluate_pawns(const Position& pos, Bitboar backward = (b | (Us == WHITE ? b << 8 : b >> 8)) & theirPawns; } + assert(passed | opposed | (attack_span_mask(Us, s) & theirPawns)); + // Test for candidate passed pawn - candidate = !passed - && !(theirPawns & file_bb(f)) - && ( count_1s_max_15(neighboring_files_bb(f) & (behind_bb(Us, r) | rank_bb(r)) & ourPawns) - - count_1s_max_15(neighboring_files_bb(f) & in_front_bb(Us, r) & theirPawns) - >= 0); - - // In order to prevent doubled passed pawns from receiving a too big - // bonus, only the frontmost passed pawn on each file is considered as - // a true passed pawn. - if (passed && (ourPawns & squares_in_front_of(Us, s))) - passed = false; + candidate = !(opposed | passed) + && (b = attack_span_mask(opposite_color(Us), s + pawn_push(Us)) & ourPawns) != EmptyBoardBB + && count_1s(b) >= count_1s(attack_span_mask(Us, s) & theirPawns); - // Score this pawn - if (passed) - set_bit(&(pi->passedPawns), s); + // Mark the pawn as passed. Pawn will be properly scored in evaluation + // because we need full attack info to evaluate passed pawns. Only the + // frontmost passed pawn on each file is considered a true passed pawn. + if (passed && !doubled) + set_bit(&(pi->passedPawns[Us]), s); + // Score this pawn if (isolated) - { - mgValue -= IsolatedPawnMidgamePenalty[f]; - egValue -= IsolatedPawnEndgamePenalty[f]; - if (!(theirPawns & file_bb(f))) - { - mgValue -= IsolatedPawnMidgamePenalty[f] / 2; - egValue -= IsolatedPawnEndgamePenalty[f] / 2; - } - } - if (doubled) - { - mgValue -= DoubledPawnMidgamePenalty[f]; - egValue -= DoubledPawnEndgamePenalty[f]; - } - if (backward) - { - mgValue -= BackwardPawnMidgamePenalty[f]; - egValue -= BackwardPawnEndgamePenalty[f]; - if (!(theirPawns & file_bb(f))) - { - mgValue -= BackwardPawnMidgamePenalty[f] / 2; - egValue -= BackwardPawnEndgamePenalty[f] / 2; - } - } - if (chain) - { - mgValue += ChainMidgameBonus[f]; - egValue += ChainEndgameBonus[f]; - } - if (candidate) - { - mgValue += CandidateMidgameBonus[relative_rank(Us, s)]; - egValue += CandidateEndgameBonus[relative_rank(Us, s)]; - } - } // while (pawns) + value -= IsolatedPawnPenalty[opposed][f]; - return Values(mgValue, egValue); -} + if (doubled) + value -= DoubledPawnPenalty[opposed][f]; + if (backward) + value -= BackwardPawnPenalty[opposed][f]; -/// PawnInfo::updateShelter calculates and caches king shelter. It is called -/// only when king square changes, about 20% of total get_king_shelter() calls. -int PawnInfo::updateShelter(const Position& pos, Color c, Square ksq) { + if (chain) + value += ChainBonus[f]; - unsigned shelter = 0; - Bitboard pawns = pos.pieces(PAWN, c) & this_and_neighboring_files_bb(ksq); - unsigned r = ksq & (7 << 3); - for (int i = 1, k = (c ? -8 : 8); i < 4; i++) - { - r += k; - shelter += BitCount8Bit[(pawns >> r) & 0xFF] * (128 >> i); + if (candidate) + value += CandidateBonus[relative_rank(Us, s)]; } - kingSquares[c] = ksq; - kingShelters[c] = shelter; - return shelter; + return value; }