X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=995a5b541e185e6a0e772e02fb879ba6c832e09a;hp=cc8e896a143b46c5cea28dcb893a69550451c64b;hb=490f67a3f89449e243c3e85feb13679f388d9e22;hpb=bfd4421f490e721958a77b8304d8ebcb574a583f diff --git a/src/material.cpp b/src/material.cpp index cc8e896a..995a5b54 100644 --- a/src/material.cpp +++ b/src/material.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) 2008-2013 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 @@ -17,389 +17,284 @@ along with this program. If not, see . */ - -//// -//// Includes -//// - +#include // For std::min #include -#include -#include +#include #include "material.h" using namespace std; - -//// -//// Local definitions -//// - namespace { - // Polynomial material balance parameters - const Value RedundantQueenPenalty = Value(320); - const Value RedundantRookPenalty = Value(554); - const int LinearCoefficients[6] = { 1709, -137, -1185, -166, 141, 59 }; - - const int QuadraticCoefficientsSameColor[][6] = { - { 0, 0, 0, 0, 0, 0 }, { 33, -6, 0, 0, 0, 0 }, { 29, 269, -12, 0, 0, 0 }, - { 0, 19, -4, 0, 0, 0 }, { -35, -10, 40, 95, 50, 0 }, { 52, 23, 78, 144, -11, -33 } }; - - const int QuadraticCoefficientsOppositeColor[][6] = { - { 0, 0, 0, 0, 0, 0 }, { -5, 0, 0, 0, 0, 0 }, { -33, 23, 0, 0, 0, 0 }, - { 17, 25, -3, 0, 0, 0 }, { 10, -2, -19, -67, 0, 0 }, { 69, 64, -41, 116, 137, 0 } }; - - // Named endgame evaluation and scaling functions, these - // are accessed direcly and not through the function maps. - EvaluationFunction EvaluateKmmKm(WHITE); - EvaluationFunction EvaluateKXK(WHITE), EvaluateKKX(BLACK); - ScalingFunction ScaleKBPsK(WHITE), ScaleKKBPs(BLACK); - ScalingFunction ScaleKQKRPs(WHITE), ScaleKRPsKQ(BLACK); - ScalingFunction ScaleKPsK(WHITE), ScaleKKPs(BLACK); - ScalingFunction ScaleKPKPw(WHITE), ScaleKPKPb(BLACK); - - typedef EndgameEvaluationFunctionBase EF; - typedef EndgameScalingFunctionBase SF; -} - - -//// -//// Classes -//// - -/// EndgameFunctions class stores endgame evaluation and scaling functions -/// in two std::map. Because STL library is not guaranteed to be thread -/// safe even for read access, the maps, although with identical content, -/// are replicated for each thread. This is faster then using locks. + // Values modified by Joona Kiiski + const Value MidgameLimit = Value(15581); + const Value EndgameLimit = Value(3998); -class EndgameFunctions { -public: - EndgameFunctions(); - ~EndgameFunctions(); - template T* get(Key key) const; + // Scale factors used when one side has no more pawns + const int NoPawnsSF[4] = { 6, 12, 32 }; -private: - template void add(const string& keyCode); + // Polynomial material balance parameters + const Value RedundantQueen = Value(320); + const Value RedundantRook = Value(554); + + // pair pawn knight bishop rook queen + const int LinearCoefficients[6] = { 1617, -162, -1172, -190, 105, 26 }; + + const int QuadraticCoefficientsSameColor[][PIECE_TYPE_NB] = { + // pair pawn knight bishop rook queen + { 7 }, // Bishop pair + { 39, 2 }, // Pawn + { 35, 271, -4 }, // Knight + { 7, 105, 4, 7 }, // Bishop + { -27, -2, 46, 100, 56 }, // Rook + { 58, 29, 83, 148, -3, -25 } // Queen + }; + + const int QuadraticCoefficientsOppositeColor[][PIECE_TYPE_NB] = { + // THEIR PIECES + // pair pawn knight bishop rook queen + { 41 }, // Bishop pair + { 37, 41 }, // Pawn + { 10, 62, 41 }, // Knight OUR PIECES + { 57, 64, 39, 41 }, // Bishop + { 50, 40, 23, -22, 41 }, // Rook + { 106, 101, 3, 151, 171, 41 } // Queen + }; + + // Endgame evaluation and scaling functions accessed direcly and not through + // the function maps because correspond to more then one material hash key. + Endgame EvaluateKmmKm[] = { Endgame(WHITE), Endgame(BLACK) }; + Endgame EvaluateKXK[] = { Endgame(WHITE), Endgame(BLACK) }; + + Endgame ScaleKBPsK[] = { Endgame(WHITE), Endgame(BLACK) }; + Endgame ScaleKQKRPs[] = { Endgame(WHITE), Endgame(BLACK) }; + Endgame ScaleKPsK[] = { Endgame(WHITE), Endgame(BLACK) }; + Endgame ScaleKPKP[] = { Endgame(WHITE), Endgame(BLACK) }; + + // Helper templates used to detect a given material distribution + template bool is_KXK(const Position& pos) { + const Color Them = (Us == WHITE ? BLACK : WHITE); + return !pos.count(Them) + && pos.non_pawn_material(Them) == VALUE_ZERO + && pos.non_pawn_material(Us) >= RookValueMg; + } - static Key buildKey(const string& keyCode); - static const string swapColors(const string& keyCode); + template bool is_KBPsKs(const Position& pos) { + return pos.non_pawn_material(Us) == BishopValueMg + && pos.count(Us) == 1 + && pos.count(Us) >= 1; + } - // Here we store two maps, for evaluate and scaling functions - pair, map > maps; + template bool is_KQKRPs(const Position& pos) { + const Color Them = (Us == WHITE ? BLACK : WHITE); + return !pos.count(Us) + && pos.non_pawn_material(Us) == QueenValueMg + && pos.count(Us) == 1 + && pos.count(Them) == 1 + && pos.count(Them) >= 1; + } - // Maps accessing functions returning const and non-const references - template const map& get() const { return maps.first; } - template map& get() { return maps.first; } -}; + /// imbalance() calculates imbalance comparing piece count of each + /// piece type for both colors. -// Explicit specializations of a member function shall be declared in -// the namespace of which the class template is a member. -template<> const map& -EndgameFunctions::get() const { return maps.second; } + template + int imbalance(const int pieceCount[][PIECE_TYPE_NB]) { -template<> map& -EndgameFunctions::get() { return maps.second; } + const Color Them = (Us == WHITE ? BLACK : WHITE); + int pt1, pt2, pc, v; + int value = 0; -//// -//// Functions -//// + // Redundancy of major pieces, formula based on Kaufman's paper + // "The Evaluation of Material Imbalances in Chess" + if (pieceCount[Us][ROOK] > 0) + value -= RedundantRook * (pieceCount[Us][ROOK] - 1) + + RedundantQueen * pieceCount[Us][QUEEN]; -/// MaterialInfoTable c'tor and d'tor, called once by each thread + // Second-degree polynomial material imbalance by Tord Romstad + for (pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; pt1++) + { + pc = pieceCount[Us][pt1]; + if (!pc) + continue; -MaterialInfoTable::MaterialInfoTable(unsigned int numOfEntries) { + v = LinearCoefficients[pt1]; - size = numOfEntries; - entries = new MaterialInfo[size]; - funcs = new EndgameFunctions(); + for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; pt2++) + v += QuadraticCoefficientsSameColor[pt1][pt2] * pieceCount[Us][pt2] + + QuadraticCoefficientsOppositeColor[pt1][pt2] * pieceCount[Them][pt2]; - if (!entries || !funcs) - { - cerr << "Failed to allocate " << numOfEntries * sizeof(MaterialInfo) - << " bytes for material hash table." << endl; - Application::exit_with_failure(); + value += pc * v; + } + return value; } -} -MaterialInfoTable::~MaterialInfoTable() { - - delete funcs; - delete [] entries; -} +} // namespace +namespace Material { -/// MaterialInfoTable::get_material_info() takes a position object as input, -/// computes or looks up a MaterialInfo object, and returns a pointer to it. -/// If the material configuration is not already present in the table, it -/// is stored there, so we don't have to recompute everything when the -/// same material configuration occurs again. +/// Material::probe() takes a position object as input, looks up a MaterialEntry +/// object, and returns a pointer to it. If the material configuration is not +/// already present in the table, it is computed and stored there, so we don't +/// have to recompute everything when the same material configuration occurs again. -MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) { +Entry* probe(const Position& pos, Table& entries, Endgames& endgames) { - Key key = pos.get_material_key(); - int index = key & (size - 1); - MaterialInfo* mi = entries + index; + Key key = pos.material_key(); + Entry* e = entries[key]; - // If mi->key matches the position's material hash key, it means that we + // If e->key matches the position's material hash key, it means that we // have analysed this material configuration before, and we can simply // return the information we found the last time instead of recomputing it. - if (mi->key == key) - return mi; + if (e->key == key) + return e; - // Clear the MaterialInfo object, and set its key - mi->clear(); - mi->key = key; + std::memset(e, 0, sizeof(Entry)); + e->key = key; + e->factor[WHITE] = e->factor[BLACK] = (uint8_t)SCALE_FACTOR_NORMAL; + e->gamePhase = game_phase(pos); // Let's look if we have a specialized evaluation function for this // particular material configuration. First we look for a fixed // configuration one, then a generic one if previous search failed. - if ((mi->evaluationFunction = funcs->get(key)) != NULL) - return mi; + if (endgames.probe(key, e->evaluationFunction)) + return e; - else if ( pos.non_pawn_material(BLACK) == Value(0) - && pos.piece_count(BLACK, PAWN) == 0 - && pos.non_pawn_material(WHITE) >= RookValueMidgame) + if (is_KXK(pos)) { - mi->evaluationFunction = &EvaluateKXK; - return mi; + e->evaluationFunction = &EvaluateKXK[WHITE]; + return e; } - else if ( pos.non_pawn_material(WHITE) == Value(0) - && pos.piece_count(WHITE, PAWN) == 0 - && pos.non_pawn_material(BLACK) >= RookValueMidgame) + + if (is_KXK(pos)) { - mi->evaluationFunction = &EvaluateKKX; - return mi; + e->evaluationFunction = &EvaluateKXK[BLACK]; + return e; } - else if ( pos.pawns() == EmptyBoardBB - && pos.rooks() == EmptyBoardBB - && pos.queens() == EmptyBoardBB) + + // Draw by insufficient material (trivial draws like KK, KBK and KNK) + if ( !pos.pieces(PAWN) + && pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) <= BishopValueMg) { - // Minor piece endgame with at least one minor piece per side and - // no pawns. Note that the case KmmK is already handled by KXK. - assert(pos.knights(WHITE) | pos.bishops(WHITE)); - assert(pos.knights(BLACK) | pos.bishops(BLACK)); + e->evaluationFunction = &EvaluateKmmKm[pos.side_to_move()]; + return e; + } - if ( pos.piece_count(WHITE, BISHOP) + pos.piece_count(WHITE, KNIGHT) <= 2 - && pos.piece_count(BLACK, BISHOP) + pos.piece_count(BLACK, KNIGHT) <= 2) + // Minor piece endgame with at least one minor piece per side and + // no pawns. Note that the case KmmK is already handled by KXK. + if (!pos.pieces(PAWN) && !pos.pieces(ROOK) && !pos.pieces(QUEEN)) + { + assert((pos.pieces(WHITE, KNIGHT) | pos.pieces(WHITE, BISHOP))); + assert((pos.pieces(BLACK, KNIGHT) | pos.pieces(BLACK, BISHOP))); + + if ( pos.count(WHITE) + pos.count(WHITE) <= 2 + && pos.count(BLACK) + pos.count(BLACK) <= 2) { - mi->evaluationFunction = &EvaluateKmmKm; - return mi; + e->evaluationFunction = &EvaluateKmmKm[pos.side_to_move()]; + return e; } } // OK, we didn't find any special evaluation function for the current // material configuration. Is there a suitable scaling function? // - // The code below is rather messy, and it could easily get worse later, - // if we decide to add more special cases. We face problems when there - // are several conflicting applicable scaling functions and we need to - // decide which one to use. - SF* sf; + // We face problems when there are several conflicting applicable + // scaling functions and we need to decide which one to use. + EndgameBase* sf; - if ((sf = funcs->get(key)) != NULL) + if (endgames.probe(key, sf)) { - mi->scalingFunction[sf->color()] = sf; - return mi; + e->scalingFunction[sf->color()] = sf; + return e; } // Generic scaling functions that refer to more then one material // distribution. Should be probed after the specialized ones. // Note that these ones don't return after setting the function. - if ( pos.non_pawn_material(WHITE) == BishopValueMidgame - && pos.piece_count(WHITE, BISHOP) == 1 - && pos.piece_count(WHITE, PAWN) >= 1) - mi->scalingFunction[WHITE] = &ScaleKBPsK; - - if ( pos.non_pawn_material(BLACK) == BishopValueMidgame - && pos.piece_count(BLACK, BISHOP) == 1 - && pos.piece_count(BLACK, PAWN) >= 1) - mi->scalingFunction[BLACK] = &ScaleKKBPs; - - if ( pos.piece_count(WHITE, PAWN) == 0 - && pos.non_pawn_material(WHITE) == QueenValueMidgame - && pos.piece_count(WHITE, QUEEN) == 1 - && pos.piece_count(BLACK, ROOK) == 1 - && pos.piece_count(BLACK, PAWN) >= 1) - mi->scalingFunction[WHITE] = &ScaleKQKRPs; - - else if ( pos.piece_count(BLACK, PAWN) == 0 - && pos.non_pawn_material(BLACK) == QueenValueMidgame - && pos.piece_count(BLACK, QUEEN) == 1 - && pos.piece_count(WHITE, ROOK) == 1 - && pos.piece_count(WHITE, PAWN) >= 1) - mi->scalingFunction[BLACK] = &ScaleKRPsKQ; - - if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) == Value(0)) + if (is_KBPsKs(pos)) + e->scalingFunction[WHITE] = &ScaleKBPsK[WHITE]; + + if (is_KBPsKs(pos)) + e->scalingFunction[BLACK] = &ScaleKBPsK[BLACK]; + + if (is_KQKRPs(pos)) + e->scalingFunction[WHITE] = &ScaleKQKRPs[WHITE]; + + else if (is_KQKRPs(pos)) + e->scalingFunction[BLACK] = &ScaleKQKRPs[BLACK]; + + Value npm_w = pos.non_pawn_material(WHITE); + Value npm_b = pos.non_pawn_material(BLACK); + + if (npm_w + npm_b == VALUE_ZERO) { - if (pos.piece_count(BLACK, PAWN) == 0) + if (!pos.count(BLACK)) { - assert(pos.piece_count(WHITE, PAWN) >= 2); - mi->scalingFunction[WHITE] = &ScaleKPsK; + assert(pos.count(WHITE) >= 2); + e->scalingFunction[WHITE] = &ScaleKPsK[WHITE]; } - else if (pos.piece_count(WHITE, PAWN) == 0) + else if (!pos.count(WHITE)) { - assert(pos.piece_count(BLACK, PAWN) >= 2); - mi->scalingFunction[BLACK] = &ScaleKKPs; + assert(pos.count(BLACK) >= 2); + e->scalingFunction[BLACK] = &ScaleKPsK[BLACK]; } - else if (pos.piece_count(WHITE, PAWN) == 1 && pos.piece_count(BLACK, PAWN) == 1) + else if (pos.count(WHITE) == 1 && pos.count(BLACK) == 1) { // This is a special case because we set scaling functions // for both colors instead of only one. - mi->scalingFunction[WHITE] = &ScaleKPKPw; - mi->scalingFunction[BLACK] = &ScaleKPKPb; + e->scalingFunction[WHITE] = &ScaleKPKP[WHITE]; + e->scalingFunction[BLACK] = &ScaleKPKP[BLACK]; } } - // Compute the space weight - if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= - 2*QueenValueMidgame + 4*RookValueMidgame + 2*KnightValueMidgame) + // No pawns makes it difficult to win, even with a material advantage + if (!pos.count(WHITE) && npm_w - npm_b <= BishopValueMg) { - int minorPieceCount = pos.piece_count(WHITE, KNIGHT) - + pos.piece_count(BLACK, KNIGHT) - + pos.piece_count(WHITE, BISHOP) - + pos.piece_count(BLACK, BISHOP); - - mi->spaceWeight = minorPieceCount * minorPieceCount; + e->factor[WHITE] = (uint8_t) + (npm_w == npm_b || npm_w < RookValueMg ? 0 : NoPawnsSF[std::min(pos.count(WHITE), 2)]); } - // Evaluate the material balance - const int pieceCount[2][6] = { { pos.piece_count(WHITE, BISHOP) > 1, pos.piece_count(WHITE, PAWN), pos.piece_count(WHITE, KNIGHT), - pos.piece_count(WHITE, BISHOP), pos.piece_count(WHITE, ROOK), pos.piece_count(WHITE, QUEEN) }, - { pos.piece_count(BLACK, BISHOP) > 1, pos.piece_count(BLACK, PAWN), pos.piece_count(BLACK, KNIGHT), - pos.piece_count(BLACK, BISHOP), pos.piece_count(BLACK, ROOK), pos.piece_count(BLACK, QUEEN) } }; - Color c, them; - int sign; - int matValue = 0; - - for (c = WHITE, sign = 1; c <= BLACK; c++, sign = -sign) + if (!pos.count(BLACK) && npm_b - npm_w <= BishopValueMg) { - // No pawns makes it difficult to win, even with a material advantage - if ( pos.piece_count(c, PAWN) == 0 - && pos.non_pawn_material(c) - pos.non_pawn_material(opposite_color(c)) <= BishopValueMidgame) - { - if ( pos.non_pawn_material(c) == pos.non_pawn_material(opposite_color(c)) - || pos.non_pawn_material(c) < RookValueMidgame) - mi->factor[c] = 0; - else - { - switch (pos.piece_count(c, BISHOP)) { - case 2: - mi->factor[c] = 32; - break; - case 1: - mi->factor[c] = 12; - break; - case 0: - mi->factor[c] = 6; - break; - } - } - } - - // Redundancy of major pieces, formula based on Kaufman's paper - // "The Evaluation of Material Imbalances in Chess" - // http://mywebpages.comcast.net/danheisman/Articles/evaluation_of_material_imbalance.htm - if (pieceCount[c][ROOK] >= 1) - matValue -= sign * ((pieceCount[c][ROOK] - 1) * RedundantRookPenalty + pieceCount[c][QUEEN] * RedundantQueenPenalty); - - them = opposite_color(c); - - // Second-degree polynomial material imbalance by Tord Romstad - // - // We use NO_PIECE_TYPE as a place holder for the bishop pair "extended piece", - // this allow us to be more flexible in defining bishop pair bonuses. - for (int pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; pt1++) - { - int c1 = sign * pieceCount[c][pt1]; - if (!c1) - continue; - - matValue += c1 * LinearCoefficients[pt1]; - - for (int pt2 = NO_PIECE_TYPE; pt2 <= pt1; pt2++) - { - matValue += c1 * pieceCount[c][pt2] * QuadraticCoefficientsSameColor[pt1][pt2]; - matValue += c1 * pieceCount[them][pt2] * QuadraticCoefficientsOppositeColor[pt1][pt2]; - } - } + e->factor[BLACK] = (uint8_t) + (npm_w == npm_b || npm_b < RookValueMg ? 0 : NoPawnsSF[std::min(pos.count(BLACK), 2)]); } - mi->value = int16_t(matValue / 16); - return mi; -} - - -/// EndgameFunctions member definitions. - -EndgameFunctions::EndgameFunctions() { - add >("KNNK"); - add >("KPK"); - add >("KBNK"); - add >("KRKP"); - add >("KRKB"); - add >("KRKN"); - add >("KQKR"); - add >("KBBKN"); - - add >("KNPK"); - add >("KRPKR"); - add >("KBPKB"); - add >("KBPPKB"); - add >("KBPKN"); - add >("KRPPKRP"); - add >("KRPPKRP"); -} - -EndgameFunctions::~EndgameFunctions() { - - for (map::iterator it = maps.first.begin(); it != maps.first.end(); ++it) - delete (*it).second; - - for (map::iterator it = maps.second.begin(); it != maps.second.end(); ++it) - delete (*it).second; -} - -Key EndgameFunctions::buildKey(const string& keyCode) { - - assert(keyCode.length() > 0 && keyCode[0] == 'K'); - assert(keyCode.length() < 8); - - stringstream s; - bool upcase = false; + // Compute the space weight + if (npm_w + npm_b >= 2 * QueenValueMg + 4 * RookValueMg + 2 * KnightValueMg) + { + int minorPieceCount = pos.count(WHITE) + pos.count(WHITE) + + pos.count(BLACK) + pos.count(BLACK); - // Build up a fen string with the given pieces, note that - // the fen string could be of an illegal position. - for (size_t i = 0; i < keyCode.length(); i++) - { - if (keyCode[i] == 'K') - upcase = !upcase; + e->spaceWeight = make_score(minorPieceCount * minorPieceCount, 0); + } - s << char(upcase? toupper(keyCode[i]) : tolower(keyCode[i])); - } - s << 8 - keyCode.length() << "/8/8/8/8/8/8/8 w -"; - return Position(s.str()).get_material_key(); + // Evaluate the material imbalance. We use PIECE_TYPE_NONE as a place holder + // for the bishop pair "extended piece", this allow us to be more flexible + // in defining bishop pair bonuses. + const int pieceCount[COLOR_NB][PIECE_TYPE_NB] = { + { pos.count(WHITE) > 1, pos.count(WHITE), pos.count(WHITE), + pos.count(WHITE) , pos.count(WHITE), pos.count(WHITE) }, + { pos.count(BLACK) > 1, pos.count(BLACK), pos.count(BLACK), + pos.count(BLACK) , pos.count(BLACK), pos.count(BLACK) } }; + + e->value = (int16_t)((imbalance(pieceCount) - imbalance(pieceCount)) / 16); + return e; } -const string EndgameFunctions::swapColors(const string& keyCode) { - // Build corresponding key for the opposite color: "KBPKN" -> "KNKBP" - size_t idx = keyCode.find("K", 1); - return keyCode.substr(idx) + keyCode.substr(0, idx); -} +/// Material::game_phase() calculates the phase given the current +/// position. Because the phase is strictly a function of the material, it +/// is stored in MaterialEntry. -template -void EndgameFunctions::add(const string& keyCode) { +Phase game_phase(const Position& pos) { - typedef typename T::Base F; + Value npm = pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK); - get().insert(pair(buildKey(keyCode), new T(WHITE))); - get().insert(pair(buildKey(swapColors(keyCode)), new T(BLACK))); + return npm >= MidgameLimit ? PHASE_MIDGAME + : npm <= EndgameLimit ? PHASE_ENDGAME + : Phase(((npm - EndgameLimit) * 128) / (MidgameLimit - EndgameLimit)); } -template -T* EndgameFunctions::get(Key key) const { - - typename map::const_iterator it(get().find(key)); - return (it != get().end() ? it->second : NULL); -} +} // namespace Material