X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=950994ef898b4843a869cd22898dbf933ada88e8;hp=37a54dd95545fcc8e2e9365f6ba219166dbbf2e5;hb=3dccdf5b835b9856bcf869fbad90ae4914a2813c;hpb=fa2478a81f42648aa3382d60280e01adb0c4536f diff --git a/src/pawns.cpp b/src/pawns.cpp index 37a54dd9..950994ef 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) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2012 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 @@ -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] = { @@ -70,47 +61,26 @@ namespace { S(34,68), S(83,166), S(0, 0), S( 0, 0) }; - #undef S -} - + const Score PawnStructureWeight = S(233, 201); -//// -//// Functions -//// - -/// PawnInfoTable c'tor and d'tor instantiated one each thread - -PawnInfoTable::PawnInfoTable() { - - entries = new PawnInfo[PawnTableSize]; + #undef S - if (!entries) - { - std::cerr << "Failed to allocate " << (PawnTableSize * sizeof(PawnInfo)) - << " bytes for pawn hash table." << std::endl; - Application::exit_with_failure(); + inline Score apply_weight(Score v, Score w) { + return make_score((int(mg_value(v)) * mg_value(w)) / 0x100, + (int(eg_value(v)) * eg_value(w)) / 0x100); } } -PawnInfoTable::~PawnInfoTable() { - - delete [] entries; -} - - -/// PawnInfoTable::get_pawn_info() takes a position object as input, computes +/// PawnInfoTable::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 +/// 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) const { - - assert(pos.is_ok()); +PawnInfo* PawnInfoTable::pawn_info(const Position& pos) const { - Key key = pos.get_pawn_key(); - unsigned index = unsigned(key & (PawnTableSize - 1)); - PawnInfo* pi = entries + index; + Key key = pos.pawn_key(); + PawnInfo* pi = probe(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 @@ -118,20 +88,24 @@ PawnInfo* PawnInfoTable::get_pawn_info(const Position& pos) const { if (pi->key == key) return pi; - // Clear the PawnInfo object, and set the key - memset(pi, 0, sizeof(PawnInfo)); - pi->kingSquares[WHITE] = pi->kingSquares[BLACK] = SQ_NONE; + // 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); - - // Evaluate pawns for both colors - pi->value = evaluate_pawns(pos, whitePawns, blackPawns, pi) - - evaluate_pawns(pos, blackPawns, whitePawns, pi); + 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 and weight the result + pi->value = evaluate_pawns(pos, wPawns, bPawns, pi) + - evaluate_pawns(pos, bPawns, wPawns, pi); + + pi->value = apply_weight(pi->value, PawnStructureWeight); + return pi; } @@ -140,54 +114,53 @@ PawnInfo* PawnInfoTable::get_pawn_info(const Position& pos) const { template Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns, - Bitboard theirPawns, PawnInfo* pi) const { + Bitboard theirPawns, PawnInfo* pi) { + + const Color Them = (Us == WHITE ? BLACK : WHITE); + Bitboard b; Square s; File f; Rank r; bool passed, isolated, doubled, opposed, chain, backward, candidate; Score value = SCORE_ZERO; - const Square* ptr = pos.piece_list_begin(Us, PAWN); - - // Initialize halfOpenFiles[] - for (f = FILE_A; f <= FILE_H; f++) - if (!(ourPawns & file_bb(f))) - pi->halfOpenFiles[Us] |= (1 << f); + const Square* pl = pos.piece_list(Us, PAWN); // Loop through all pawns of the current color and score each pawn - while ((s = *ptr++) != SQ_NONE) + while ((s = *pl++) != SQ_NONE) { - assert(pos.piece_on(s) == piece_of_color_and_type(Us, PAWN)); + assert(pos.piece_on(s) == make_piece(Us, PAWN)); + + f = file_of(s); + r = rank_of(s); - f = square_file(s); - r = square_rank(s); + // This file cannot be half open + pi->halfOpenFiles[Us] &= ~(1 << f); - // Our rank plus previous one. Used for chain detection. + // Our rank plus previous one. Used for chain detection b = rank_bb(r) | rank_bb(Us == WHITE ? r - Rank(1) : r + Rank(1)); - // Passed, isolated, doubled or member of a pawn - // chain (but not the backward one) ? + // 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_behind(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; + isolated = !(ourPawns & adjacent_files_bb(f)); + chain = ourPawns & adjacent_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 the pawn is passed, isolated, or member of a pawn chain it cannot + // be backward. If there are friendly pawns behind on adjacent files + // or if can capture an enemy pawn it cannot be backward either. if ( !(passed | isolated | chain) - && !(ourPawns & attack_span_mask(opposite_color(Us), s)) + && !(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 + // pawn on adjacent files. We now check whether the pawn is + // backward by looking in the forward direction on the adjacent // files, and seeing whether we meet a friendly or an enemy pawn first. b = pos.attacks_from(s, Us); @@ -196,52 +169,72 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns, 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; } - assert(passed | opposed | (attack_span_mask(Us, s) & theirPawns)); - - // Test for candidate passed pawn - candidate = !(opposed | passed) - && (b = attack_span_mask(opposite_color(Us), s + pawn_push(Us)) & ourPawns) != EmptyBoardBB - && count_1s_max_15(b) >= count_1s_max_15(attack_span_mask(Us, s) & theirPawns); + 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 adjacent files is higher or equal than the number of + // enemy pawns in the forward direction on the adjacent files. + candidate = !(opposed | passed | backward | isolated) + && (b = attack_span_mask(Them, s + pawn_push(Us)) & ourPawns) != 0 + && popcount(b) >= popcount(attack_span_mask(Us, s) & theirPawns); - // Mark the pawn as passed. Pawn will be properly scored in evaluation - // because we need full attack info to evaluate passed pawns. - if (passed) - set_bit(&(pi->passedPawns[Us]), 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) + pi->passedPawns[Us] |= s; // Score this pawn if (isolated) - { - value -= IsolatedPawnPenalty[f]; - if (!opposed) - value -= IsolatedPawnPenalty[f] / 2; - } + value -= IsolatedPawnPenalty[opposed][f]; + if (doubled) - value -= DoubledPawnPenalty[f]; + value -= DoubledPawnPenalty[opposed][f]; if (backward) - { - value -= BackwardPawnPenalty[f]; - if (!opposed) - value -= BackwardPawnPenalty[f] / 2; - } + value -= BackwardPawnPenalty[opposed][f]; + if (chain) value += ChainBonus[f]; if (candidate) value += CandidateBonus[relative_rank(Us, s)]; } - return value; } + +/// 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; + + if (relative_rank(Us, ksq) <= RANK_4) + { + pawns = pos.pieces(PAWN, Us) & this_and_adjacent_files_bb(file_of(ksq)); + r = ksq & (7 << 3); + for (int i = 0; i < 3; i++) + { + r += Shift; + shelter += BitCount8Bit[(pawns >> r) & 0xFF] << (6 - i); + } + } + 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);