X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=997aa2148815142da303cab5acb499bd78d0d6e9;hp=c6d390b32efb0ea9e9a22276605a0c688485a0ae;hb=2f1935078da225c90f7887ed8c345cc7baebcfcc;hpb=fc89dbcab2616603ba6edbf6277c3edecfc3a64a diff --git a/src/pawns.cpp b/src/pawns.cpp index c6d390b3..997aa214 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -17,46 +17,37 @@ along with this program. If not, see . */ - -//// -//// Includes -//// - #include -#include +#include "bitboard.h" #include "bitcount.h" #include "pawns.h" #include "position.h" - -//// -//// Local definitions -//// - namespace { - /// Constants and variables - #define S(mg, eg) make_score(mg, eg) - // Doubled pawn penalty by file - const Score DoubledPawnPenalty[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) - }; - - // Isolated pawn penalty by file - const Score IsolatedPawnPenalty[8] = { - 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 file - const Score BackwardPawnPenalty[8] = { - S(20, 28), S(29, 31), S(33, 31), S(33, 31), - S(33, 31), S(33, 31), S(29, 31), S(20, 28) - }; + // 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] = { @@ -70,91 +61,21 @@ namespace { S(34,68), S(83,166), S(0, 0), S( 0, 0) }; - // UnpairedPawnsTable[] gives a score according to the number - // of panws that do not have an enemy pawn in front of them. - const int UnpairedPawnsTable[8] = { 32, 48, 64, 80, 96, 112, 128, 128 }; - - // 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 }; - -} - - -//// -//// 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; + #undef S } /// 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 an 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 @@ -162,19 +83,21 @@ PawnInfo* PawnInfoTable::get_pawn_info(const Position& pos) { if (pi->key == key) return pi; - // Clear the PawnInfo object, and set the key - pi->clear(); + // Initialize PawnInfo entry pi->key = key; + pi->passedPawns[WHITE] = pi->passedPawns[BLACK] = 0; + pi->kingSquares[WHITE] = pi->kingSquares[BLACK] = SQ_NONE; + pi->halfOpenFiles[WHITE] = pi->halfOpenFiles[BLACK] = 0xFF; // 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 - pi->value = evaluate_pawns(pos, whitePawns, blackPawns, pi) - - evaluate_pawns(pos, blackPawns, whitePawns, pi); + pi->value = evaluate_pawns(pos, wPawns, bPawns, pi) + - evaluate_pawns(pos, bPawns, wPawns, pi); return pi; } @@ -183,189 +106,128 @@ PawnInfo* PawnInfoTable::get_pawn_info(const Position& pos) { template Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns, - Bitboard theirPawns, PawnInfo* pi) { + Bitboard theirPawns, PawnInfo* pi) const { + + const BitCountType Max15 = CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15; + const Color Them = (Us == WHITE ? BLACK : WHITE); + + Bitboard b; Square s; File f; Rank r; bool passed, isolated, doubled, opposed, chain, backward, candidate; - int bonus; - Score value = make_score(0, 0); + Score value = SCORE_ZERO; const Square* ptr = pos.piece_list_begin(Us, PAWN); - int unpairedPawnsNum = pos.piece_count(Us, PAWN); - - // Initialize pawn storm scores by giving bonuses for open files - for (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); - } // Loop through all pawns of the current color and score each pawn while ((s = *ptr++) != SQ_NONE) { + assert(pos.piece_on(s) == make_piece(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 = !(theirPawns & passed_pawn_mask(Us, s)); - isolated = !(ourPawns & neighboring_files_bb(s)); - doubled = ourPawns & squares_behind(Us, s); - opposed = theirPawns & squares_in_front_of(Us, s); - - // Decrease number of unpaired pawns - if (opposed) - unpairedPawnsNum--; - - // 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) - { - // Give a bonus according to the distance of the nearest enemy pawn - Square s2 = pop_1st_bit(&b); - int v = StormLeverBonus[f] - 2 * square_distance(s, s2); - - // If enemy pawn has no pawn beside itself is particularly vulnerable. - // Big bonus, especially against a weakness on the rook file - if (!(theirPawns & neighboring_files_bb(s2) & rank_bb(s2))) - v *= (square_file(s2) == FILE_H ? 4 : 2); - - bonus += v; - } - } - 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) - { - // Give a bonus according to the distance of the nearest enemy pawn - Square s2 = pop_1st_bit(&b); - int v = StormLeverBonus[f] - 4 * square_distance(s, s2); - - // If enemy pawn has no pawn beside itself is particularly vulnerable. - // Big bonus, especially against a weakness on the rook file - if (!(theirPawns & neighboring_files_bb(s2) & rank_bb(s2))) - v *= (square_file(s2) == FILE_A ? 4 : 2); - - bonus += v; - } - } - pi->qsStormValue[Us] += bonus; + // Our rank plus previous one. Used for chain detection + b = rank_bb(r) | rank_bb(Us == WHITE ? r - Rank(1) : r + Rank(1)); - // 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))); + // Flag the pawn as 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 - // - // 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 + backward = false; + + // If the pawn is passed, isolated, or member of a pawn chain it cannot + // be backward. If there are friendly pawns behind on neighboring files + // or if can capture an enemy pawn it cannot be backward either. + if ( !(passed | isolated | chain) + && !(ourPawns & attack_span_mask(Them, 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. while (!(b & (ourPawns | theirPawns))) Us == WHITE ? b <<= 8 : b >>= 8; - // The friendly pawn needs to be at least two ranks closer than the enemy - // pawn in order to help the potentially backward pawn advance. + // The friendly pawn needs to be at least two ranks closer than the + // enemy pawn in order to help the potentially backward pawn advance. backward = (b | (Us == WHITE ? b << 8 : b >> 8)) & theirPawns; } - // Test for candidate passed pawn - candidate = !passed - && !opposed - && ( 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); + assert(opposed | passed | (attack_span_mask(Us, s) & theirPawns)); - // 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; + // A not passed pawn is a candidate to become passed if it is free to + // advance and if the number of friendly pawns beside or behind this + // pawn on neighboring files is higher or equal than the number of + // enemy pawns in the forward direction on the neighboring files. + candidate = !(opposed | passed | backward | isolated) + && (b = attack_span_mask(Them, 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); + // Passed pawns 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) - { - value -= IsolatedPawnPenalty[f]; - if (!(theirPawns & file_bb(f))) - value -= IsolatedPawnPenalty[f] / 2; - } + value -= IsolatedPawnPenalty[opposed][f]; + if (doubled) - value -= DoubledPawnPenalty[f]; + value -= DoubledPawnPenalty[opposed][f]; if (backward) - { - value -= BackwardPawnPenalty[f]; - if (!(theirPawns & file_bb(f))) - value -= BackwardPawnPenalty[f] / 2; - } + value -= BackwardPawnPenalty[opposed][f]; + if (chain) value += ChainBonus[f]; if (candidate) value += CandidateBonus[relative_rank(Us, s)]; } - - // Calculate a scale factor to be used to evaluate if position is drawish - pi->factor[Us] = UnpairedPawnsTable[unpairedPawnsNum]; - return value; } -/// 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) { +/// PawnInfo::updateShelter() calculates and caches king shelter. It is called +/// only when king square changes, about 20% of total king_shelter() calls. +template +Score PawnInfo::updateShelter(const Position& pos, Square ksq) { + + const int Shift = (Us == WHITE ? 8 : -8); + + Bitboard pawns; + int r, shelter = 0; - 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++) + if (relative_rank(Us, ksq) <= RANK_4) { - r += k; - shelter += BitCount8Bit[(pawns >> r) & 0xFF] * (128 >> i); + pawns = pos.pieces(PAWN, Us) & this_and_neighboring_files_bb(ksq); + r = ksq & (7 << 3); + for (int i = 0; i < 3; i++) + { + r += Shift; + shelter += BitCount8Bit[(pawns >> r) & 0xFF] * (64 >> i); + } } - kingSquares[c] = ksq; - kingShelters[c] = shelter; - return shelter; + kingSquares[Us] = ksq; + kingShelters[Us] = make_score(shelter, 0); + return kingShelters[Us]; } + +// Explicit template instantiation +template Score PawnInfo::updateShelter(const Position& pos, Square ksq); +template Score PawnInfo::updateShelter(const Position& pos, Square ksq);