X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=f5001c99baef8743d9efa777af7268a9be936e5a;hp=3fc05db8fc78e09c928f2464590d032988099b59;hb=b5d5646c840d63710552fdaf2521a054dd3b8a18;hpb=20e87389019187dd7586d3ffb12b632d5ec5d048 diff --git a/src/material.cpp b/src/material.cpp index 3fc05db8..f5001c99 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) 2008-2010 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 @@ -17,109 +17,76 @@ along with this program. If not, see . */ - -//// -//// Includes -//// - #include -#include -#include +#include #include "material.h" -using std::string; - -//// -//// Local definitions -//// +using namespace std; namespace { // Values modified by Joona Kiiski - const Value BishopPairMidgameBonus = Value(109); - const Value BishopPairEndgameBonus = Value(97); - - Key KNNKMaterialKey, KKNNMaterialKey; - - // Unmapped endgame evaluation and scaling functions, these - // are accessed direcly and not through the function maps. - EvaluationFunction EvaluateKmmKm(WHITE); - EvaluationFunction EvaluateKXK(WHITE), EvaluateKKX(BLACK); - ScalingFunction ScaleKBPK(WHITE), ScaleKKBP(BLACK); - ScalingFunction ScaleKQKRP(WHITE), ScaleKRPKQ(BLACK); - ScalingFunction ScaleKPsK(WHITE), ScaleKKPs(BLACK); - ScalingFunction ScaleKPKPw(WHITE), ScaleKPKPb(BLACK); -} - - -//// -//// Classes -//// - -typedef EndgameEvaluationFunctionBase EF; -typedef EndgameScalingFunctionBase SF; - -/// See header for a class description. It is declared here to avoid -/// to include in the header file. - -class EndgameFunctions { -public: - EndgameFunctions(); - ~EndgameFunctions(); - template T* get(Key key) const; - -private: - template void add(const string& keyCode); - - static Key buildKey(const string& keyCode); - static const string swapColors(const string& keyCode); - - std::map EEFmap; - std::map ESFmap; - - // Maps accessing functions for const and non-const references - template const std::map& map() const { return EEFmap; } - template std::map& map() { return EEFmap; } -}; - -// Explicit specializations of a member function shall be declared in -// the namespace of which the class template is a member. -template<> const std::map& -EndgameFunctions::map() const { return ESFmap; } - -template<> std::map& -EndgameFunctions::map() { return ESFmap; } - - -//// -//// Functions -//// - - -/// Constructor for the MaterialInfoTable class + const Value MidgameLimit = Value(15581); + const Value EndgameLimit = Value(3998); + + // Scale factors used when one side has no more pawns + const uint8_t NoPawnsSF[4] = { 6, 12, 32 }; + + // Polynomial material balance parameters + const Value RedundantQueenPenalty = Value(320); + const Value RedundantRookPenalty = Value(554); + + const int LinearCoefficients[6] = { 1617, -162, -1172, -190, 105, 26 }; + + const int QuadraticCoefficientsSameColor[][8] = { + { 7, 7, 7, 7, 7, 7 }, { 39, 2, 7, 7, 7, 7 }, { 35, 271, -4, 7, 7, 7 }, + { 7, 25, 4, 7, 7, 7 }, { -27, -2, 46, 100, 56, 7 }, { 58, 29, 83, 148, -3, -25 } }; + + const int QuadraticCoefficientsOppositeColor[][8] = { + { 41, 41, 41, 41, 41, 41 }, { 37, 41, 41, 41, 41, 41 }, { 10, 62, 41, 41, 41, 41 }, + { 57, 64, 39, 41, 41, 41 }, { 50, 40, 23, -22, 41, 41 }, { 106, 101, 3, 151, 171, 41 } }; + + // 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.non_pawn_material(Them) == VALUE_ZERO + && pos.piece_count(Them, PAWN) == 0 + && pos.non_pawn_material(Us) >= RookValueMidgame; + } -MaterialInfoTable::MaterialInfoTable(unsigned int numOfEntries) { + template bool is_KBPsKs(const Position& pos) { + return pos.non_pawn_material(Us) == BishopValueMidgame + && pos.piece_count(Us, BISHOP) == 1 + && pos.piece_count(Us, PAWN) >= 1; + } - size = numOfEntries; - entries = new MaterialInfo[size]; - funcs = new EndgameFunctions(); - if (!entries || !funcs) - { - std::cerr << "Failed to allocate " << (numOfEntries * sizeof(MaterialInfo)) - << " bytes for material hash table." << std::endl; - Application::exit_with_failure(); + template bool is_KQKRPs(const Position& pos) { + const Color Them = (Us == WHITE ? BLACK : WHITE); + return pos.piece_count(Us, PAWN) == 0 + && pos.non_pawn_material(Us) == QueenValueMidgame + && pos.piece_count(Us, QUEEN) == 1 + && pos.piece_count(Them, ROOK) == 1 + && pos.piece_count(Them, PAWN) >= 1; } -} +} // namespace -/// Destructor for the MaterialInfoTable class -MaterialInfoTable::~MaterialInfoTable() { +/// MaterialInfoTable c'tor and d'tor allocate and free the space for Endgames - delete funcs; - delete [] entries; -} +MaterialInfoTable::MaterialInfoTable() { funcs = new Endgames(); } +MaterialInfoTable::~MaterialInfoTable() { delete funcs; } /// MaterialInfoTable::get_material_info() takes a position object as input, @@ -128,11 +95,10 @@ MaterialInfoTable::~MaterialInfoTable() { /// is 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) { +MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) const { Key key = pos.get_material_key(); - int index = key & (size - 1); - MaterialInfo* mi = entries + index; + MaterialInfo* mi = find(key); // If mi->key matches the position's material hash key, it means that we // have analysed this material configuration before, and we can simply @@ -140,51 +106,43 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) { if (mi->key == key) return mi; - // Clear the MaterialInfo object, and set its key - mi->clear(); + // Initialize MaterialInfo entry + memset(mi, 0, sizeof(MaterialInfo)); mi->key = key; + mi->factor[WHITE] = mi->factor[BLACK] = (uint8_t)SCALE_FACTOR_NORMAL; - // A special case before looking for a specialized evaluation function - // KNN vs K is a draw. - if (key == KNNKMaterialKey || key == KKNNMaterialKey) - { - mi->factor[WHITE] = mi->factor[BLACK] = 0; - return mi; - } + // Store game phase + mi->gamePhase = MaterialInfoTable::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) + if ((mi->evaluationFunction = funcs->get >(key)) != NULL) return mi; - 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; + mi->evaluationFunction = &EvaluateKXK[WHITE]; return mi; } - 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; + mi->evaluationFunction = &EvaluateKXK[BLACK]; return mi; } - else if ( pos.pawns() == EmptyBoardBB - && pos.rooks() == EmptyBoardBB - && pos.queens() == EmptyBoardBB) + + if (!pos.pieces(PAWN) && !pos.pieces(ROOK) && !pos.pieces(QUEEN)) { - // Minor piece endgame with at least one minor piece per side, - // and no pawns. - assert(pos.knights(WHITE) | pos.bishops(WHITE)); - assert(pos.knights(BLACK) | pos.bishops(BLACK)); + // 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.pieces(KNIGHT, WHITE) | pos.pieces(BISHOP, WHITE))); + assert((pos.pieces(KNIGHT, BLACK) | pos.pieces(BISHOP, BLACK))); if ( pos.piece_count(WHITE, BISHOP) + pos.piece_count(WHITE, KNIGHT) <= 2 && pos.piece_count(BLACK, BISHOP) + pos.piece_count(BLACK, KNIGHT) <= 2) { - mi->evaluationFunction = &EvaluateKmmKm; + mi->evaluationFunction = &EvaluateKmmKm[WHITE]; return mi; } } @@ -192,211 +150,136 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) { // 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 ((sf = funcs->get >(key)) != NULL) { mi->scalingFunction[sf->color()] = sf; return mi; } - if ( pos.non_pawn_material(WHITE) == BishopValueMidgame - && pos.piece_count(WHITE, BISHOP) == 1 - && pos.piece_count(WHITE, PAWN) >= 1) - mi->scalingFunction[WHITE] = &ScaleKBPK; - - if ( pos.non_pawn_material(BLACK) == BishopValueMidgame - && pos.piece_count(BLACK, BISHOP) == 1 - && pos.piece_count(BLACK, PAWN) >= 1) - mi->scalingFunction[BLACK] = &ScaleKKBP; - - 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] = &ScaleKQKRP; - - 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] = &ScaleKRPKQ; - - if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) == Value(0)) + // 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 (is_KBPsKs(pos)) + mi->scalingFunction[WHITE] = &ScaleKBPsK[WHITE]; + + if (is_KBPsKs(pos)) + mi->scalingFunction[BLACK] = &ScaleKBPsK[BLACK]; + + if (is_KQKRPs(pos)) + mi->scalingFunction[WHITE] = &ScaleKQKRPs[WHITE]; + + else if (is_KQKRPs(pos)) + mi->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) { assert(pos.piece_count(WHITE, PAWN) >= 2); - mi->scalingFunction[WHITE] = &ScaleKPsK; + mi->scalingFunction[WHITE] = &ScaleKPsK[WHITE]; } else if (pos.piece_count(WHITE, PAWN) == 0) { assert(pos.piece_count(BLACK, PAWN) >= 2); - mi->scalingFunction[BLACK] = &ScaleKKPs; + mi->scalingFunction[BLACK] = &ScaleKPsK[BLACK]; } else if (pos.piece_count(WHITE, PAWN) == 1 && pos.piece_count(BLACK, PAWN) == 1) { - mi->scalingFunction[WHITE] = &ScaleKPKPw; - mi->scalingFunction[BLACK] = &ScaleKPKPb; + // This is a special case because we set scaling functions + // for both colors instead of only one. + mi->scalingFunction[WHITE] = &ScaleKPKP[WHITE]; + mi->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.piece_count(WHITE, PAWN) == 0 && npm_w - npm_b <= BishopValueMidgame) { - 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; + mi->factor[WHITE] = + (npm_w == npm_b || npm_w < RookValueMidgame ? 0 : NoPawnsSF[Min(pos.piece_count(WHITE, BISHOP), 2)]); } - // Evaluate the material balance - - Color c; - int sign; - Value egValue = Value(0); - Value mgValue = Value(0); + if (pos.piece_count(BLACK, PAWN) == 0 && npm_b - npm_w <= BishopValueMidgame) + { + mi->factor[BLACK] = + (npm_w == npm_b || npm_b < RookValueMidgame ? 0 : NoPawnsSF[Min(pos.piece_count(BLACK, BISHOP), 2)]); + } - for (c = WHITE, sign = 1; c <= BLACK; c++, sign = -sign) + // Compute the space weight + if (npm_w + npm_b >= 2 * QueenValueMidgame + 4 * RookValueMidgame + 2 * KnightValueMidgame) { - // 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; - } - } - } - - // Bishop pair - if (pos.piece_count(c, BISHOP) >= 2) - { - mgValue += sign * BishopPairMidgameBonus; - egValue += sign * BishopPairEndgameBonus; - } - - // Knights are stronger when there are many pawns on the board. The - // formula is taken from Larry Kaufman's paper "The Evaluation of Material - // Imbalances in Chess": - // http://mywebpages.comcast.net/danheisman/Articles/evaluation_of_material_imbalance.htm - mgValue += sign * Value(pos.piece_count(c, KNIGHT)*(pos.piece_count(c, PAWN)-5)*16); - egValue += sign * Value(pos.piece_count(c, KNIGHT)*(pos.piece_count(c, PAWN)-5)*16); - - // Redundancy of major pieces, again based on Kaufman's paper: - if (pos.piece_count(c, ROOK) >= 1) - { - Value v = Value((pos.piece_count(c, ROOK) - 1) * 32 + pos.piece_count(c, QUEEN) * 16); - mgValue -= sign * v; - egValue -= sign * v; - } + int minorPieceCount = pos.piece_count(WHITE, KNIGHT) + pos.piece_count(WHITE, BISHOP) + + pos.piece_count(BLACK, KNIGHT) + pos.piece_count(BLACK, BISHOP); + + mi->spaceWeight = minorPieceCount * minorPieceCount; } - mi->mgValue = int16_t(mgValue); - mi->egValue = int16_t(egValue); - return mi; -} + // 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[2][8] = { + { 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) } }; -/// EndgameFunctions member definitions. This class is used to store the maps -/// of end game and scaling functions that MaterialInfoTable will query for -/// each key. The maps are constant and are populated only at construction, -/// but are per-thread instead of globals to avoid expensive locks needed -/// because std::map is not guaranteed to be thread-safe even if accessed -/// only for a lookup. - -EndgameFunctions::EndgameFunctions() { - - KNNKMaterialKey = buildKey("KNNK"); - KKNNMaterialKey = buildKey("KKNN"); - - 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"); + mi->value = (int16_t)(imbalance(pieceCount) - imbalance(pieceCount)) / 16; + return mi; } -EndgameFunctions::~EndgameFunctions() { - for (std::map::iterator it = EEFmap.begin(); it != EEFmap.end(); ++it) - delete (*it).second; +/// MaterialInfoTable::imbalance() calculates imbalance comparing piece count of each +/// piece type for both colors. - for (std::map::iterator it = ESFmap.begin(); it != ESFmap.end(); ++it) - delete (*it).second; -} +template +int MaterialInfoTable::imbalance(const int pieceCount[][8]) { -Key EndgameFunctions::buildKey(const string& keyCode) { + const Color Them = (Us == WHITE ? BLACK : WHITE); - assert(keyCode.length() > 0 && keyCode[0] == 'K'); - assert(keyCode.length() < 8); + int pt1, pt2, pc, v; + int value = 0; - std::stringstream s; - bool upcase = false; + // Redundancy of major pieces, formula based on Kaufman's paper + // "The Evaluation of Material Imbalances in Chess" + if (pieceCount[Us][ROOK] > 0) + value -= RedundantRookPenalty * (pieceCount[Us][ROOK] - 1) + + RedundantQueenPenalty * pieceCount[Us][QUEEN]; - // Build up a fen substring 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; + // Second-degree polynomial material imbalance by Tord Romstad + for (pt1 = PIECE_TYPE_NONE; pt1 <= QUEEN; pt1++) + { + pc = pieceCount[Us][pt1]; + if (!pc) + continue; - 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(); -} + v = LinearCoefficients[pt1]; -const string EndgameFunctions::swapColors(const string& keyCode) { + for (pt2 = PIECE_TYPE_NONE; pt2 <= pt1; pt2++) + v += QuadraticCoefficientsSameColor[pt1][pt2] * pieceCount[Us][pt2] + + QuadraticCoefficientsOppositeColor[pt1][pt2] * pieceCount[Them][pt2]; - // Build corresponding key for the opposite color: "KBPKN" -> "KNKBP" - size_t idx = keyCode.find("K", 1); - return keyCode.substr(idx) + keyCode.substr(0, idx); + value += pc * v; + } + return value; } -template -void EndgameFunctions::add(const string& keyCode) { - typedef typename T::Base F; +/// MaterialInfoTable::game_phase() calculates the phase given the current +/// position. Because the phase is strictly a function of the material, it +/// is stored in MaterialInfo. - map().insert(std::pair(buildKey(keyCode), new T(WHITE))); - map().insert(std::pair(buildKey(swapColors(keyCode)), new T(BLACK))); -} +Phase MaterialInfoTable::game_phase(const Position& pos) { -template -T* EndgameFunctions::get(Key key) const { + Value npm = pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK); - typename std::map::const_iterator it(map().find(key)); - return (it != map().end() ? it->second : NULL); + return npm >= MidgameLimit ? PHASE_MIDGAME + : npm <= EndgameLimit ? PHASE_ENDGAME + : Phase(((npm - EndgameLimit) * 128) / (MidgameLimit - EndgameLimit)); }