X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=f0ee5f682d02cada44957745849684613f3e4196;hp=ce7d7ab591881c2a030ac57efd954822c6ad9425;hb=6b7efa0cd14b73416c9030462f79a02bbfc7ad2c;hpb=73cce873de9ae241d30d405893dcc25e85293b98 diff --git a/src/material.cpp b/src/material.cpp index ce7d7ab5..f0ee5f68 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 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 @@ -23,10 +23,13 @@ //// #include +#include #include #include "material.h" +using namespace std; + //// //// Local definitions @@ -34,144 +37,118 @@ namespace { - const Value BishopPairMidgameBonus = Value(100); - const Value BishopPairEndgameBonus = Value(100); + // Values modified by Joona Kiiski + const Value MidgameLimit = Value(15581); + const Value EndgameLimit = Value(3998); - Key KRPKRMaterialKey, KRKRPMaterialKey; - Key KNNKMaterialKey, KKNNMaterialKey; - Key KBPKBMaterialKey, KBKBPMaterialKey; - Key KBPKNMaterialKey, KNKBPMaterialKey; - Key KNPKMaterialKey, KKNPMaterialKey; - Key KPKPMaterialKey; - Key KRPPKRPMaterialKey, KRPKRPPMaterialKey; + // Polynomial material balance parameters + const Value RedundantQueenPenalty = Value(320); + const Value RedundantRookPenalty = Value(554); - std::map EEFmap; + const int LinearCoefficients[6] = { 1617, -162, -1172, -190, 105, 26 }; - void EEFAdd(Key k, EndgameEvaluationFunction* f) { + const int QuadraticCoefficientsSameColor[][6] = { + { 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 } }; - EEFmap.insert(std::pair(k, f)); - } + const int QuadraticCoefficientsOppositeColor[][6] = { + { 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 } }; + + // 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; } //// -//// Functions +//// Classes //// -/// MaterialInfo::init() is called during program initialization. It -/// precomputes material hash keys for a few basic endgames, in order -/// to make it easy to recognize such endgames when they occur. - -void MaterialInfo::init() { - - typedef Key ZM[2][8][16]; - const ZM& z = Position::zobMaterial; - - static const Color W = WHITE; - static const Color B = BLACK; - - EEFAdd(z[W][PAWN][1], &EvaluateKPK); - EEFAdd(z[B][PAWN][1], &EvaluateKKP); - - EEFAdd(z[W][BISHOP][1] ^ z[W][KNIGHT][1], &EvaluateKBNK); - EEFAdd(z[B][BISHOP][1] ^ z[B][KNIGHT][1], &EvaluateKKBN); - EEFAdd(z[W][ROOK][1] ^ z[B][PAWN][1], &EvaluateKRKP); - EEFAdd(z[W][PAWN][1] ^ z[B][ROOK][1], &EvaluateKPKR); - EEFAdd(z[W][ROOK][1] ^ z[B][BISHOP][1], &EvaluateKRKB); - EEFAdd(z[W][BISHOP][1] ^ z[B][ROOK][1], &EvaluateKBKR); - EEFAdd(z[W][ROOK][1] ^ z[B][KNIGHT][1], &EvaluateKRKN); - EEFAdd(z[W][KNIGHT][1] ^ z[B][ROOK][1], &EvaluateKNKR); - EEFAdd(z[W][QUEEN][1] ^ z[B][ROOK][1], &EvaluateKQKR); - EEFAdd(z[W][ROOK][1] ^ z[B][QUEEN][1], &EvaluateKRKQ); - - KRPKRMaterialKey = z[W][ROOK][1] - ^ z[W][PAWN][1] - ^ z[B][ROOK][1]; - - KRKRPMaterialKey = z[W][ROOK][1] - ^ z[B][ROOK][1] - ^ z[B][PAWN][1]; - - KRPPKRPMaterialKey = - z[W][ROOK][1] ^ - z[W][PAWN][1] ^ - z[W][PAWN][2] ^ - z[B][ROOK][1] ^ - z[B][PAWN][1]; - KRPKRPPMaterialKey = - z[W][ROOK][1] ^ - z[W][PAWN][1] ^ - z[B][ROOK][1] ^ - z[B][PAWN][1] ^ - z[B][PAWN][2]; - KNNKMaterialKey = - z[W][KNIGHT][1] ^ - z[W][KNIGHT][2]; - KKNNMaterialKey = - z[B][KNIGHT][1] ^ - z[B][KNIGHT][2]; - KBPKBMaterialKey = - z[W][BISHOP][1] ^ - z[W][PAWN][1] ^ - z[B][BISHOP][1]; - KBKBPMaterialKey = - z[W][BISHOP][1] ^ - z[B][BISHOP][1] ^ - z[B][PAWN][1]; - KBPKNMaterialKey = - z[W][BISHOP][1] ^ - z[W][PAWN][1] ^ - z[B][KNIGHT][1]; - KNKBPMaterialKey = - z[W][KNIGHT][1] ^ - z[B][BISHOP][1] ^ - z[B][PAWN][1]; - KNPKMaterialKey = - z[W][KNIGHT][1] ^ - z[W][PAWN][1]; - KKNPMaterialKey = - z[B][KNIGHT][1] ^ - z[B][PAWN][1]; - KPKPMaterialKey = - z[W][PAWN][1] ^ - z[B][PAWN][1]; +/// 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. +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); + + // Here we store two maps, for evaluate and scaling functions + pair, map > maps; + + // Maps accessing functions returning const and non-const references + template const map& get() const { return maps.first; } + template map& get() { return maps.first; } +}; + +// 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<> map& +EndgameFunctions::get() { return maps.second; } -/// Constructor for the MaterialInfoTable class. +//// +//// Functions +//// -MaterialInfoTable::MaterialInfoTable(unsigned numOfEntries) { +/// MaterialInfoTable c'tor and d'tor, called once by each thread + +MaterialInfoTable::MaterialInfoTable(unsigned int numOfEntries) { size = numOfEntries; entries = new MaterialInfo[size]; - if (!entries) + funcs = new EndgameFunctions(); + + if (!entries || !funcs) { - std::cerr << "Failed to allocate " << (numOfEntries * sizeof(MaterialInfo)) - << " bytes for material hash table." << std::endl; - exit(EXIT_FAILURE); + cerr << "Failed to allocate " << numOfEntries * sizeof(MaterialInfo) + << " bytes for material hash table." << endl; + Application::exit_with_failure(); } - clear(); } - -/// Destructor for the MaterialInfoTable class. - MaterialInfoTable::~MaterialInfoTable() { + delete funcs; delete [] entries; } -/// MaterialInfoTable::clear() clears a material hash table by setting -/// all entries to 0. +/// 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. -void MaterialInfoTable::clear() { +Phase MaterialInfoTable::game_phase(const Position& pos) { - memset(entries, 0, size * sizeof(MaterialInfo)); -} + Value npm = pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK); + if (npm >= MidgameLimit) + return PHASE_MIDGAME; + else if (npm <= EndgameLimit) + return PHASE_ENDGAME; + + return Phase(((npm - EndgameLimit) * 128) / (MidgameLimit - EndgameLimit)); +} /// MaterialInfoTable::get_material_info() takes a position object as input, /// computes or looks up a MaterialInfo object, and returns a pointer to it. @@ -179,186 +156,275 @@ void MaterialInfoTable::clear() { /// 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) { Key key = pos.get_material_key(); int index = key & (size - 1); - MaterialInfo *mi = entries + index; + MaterialInfo* mi = entries + index; // If mi->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; + // return the information we found the last time instead of recomputing it. + if (mi->key == key) + return mi; - // Clear the MaterialInfo object, and set its key: + // Clear the MaterialInfo object, and set its key mi->clear(); mi->key = key; - // 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 - if (EEFmap.find(key) != EEFmap.end()) - { - mi->evaluationFunction = EEFmap[key]; + // 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; - } + else if ( pos.non_pawn_material(BLACK) == Value(0) && pos.piece_count(BLACK, PAWN) == 0 - && pos.non_pawn_material(WHITE) >= RookValueEndgame) + && pos.non_pawn_material(WHITE) >= RookValueMidgame) { mi->evaluationFunction = &EvaluateKXK; return mi; } else if ( pos.non_pawn_material(WHITE) == Value(0) && pos.piece_count(WHITE, PAWN) == 0 - && pos.non_pawn_material(BLACK) >= RookValueEndgame) + && pos.non_pawn_material(BLACK) >= RookValueMidgame) { mi->evaluationFunction = &EvaluateKKX; return mi; } + else if ( pos.pieces(PAWN) == EmptyBoardBB + && pos.pieces(ROOK) == EmptyBoardBB + && pos.pieces(QUEEN) == EmptyBoardBB) + { + // 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; + return mi; + } + } // 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 + // 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; - if(key == KRPKRMaterialKey) { - mi->scalingFunction[WHITE] = &ScaleKRPKR; - return mi; - } - if(key == KRKRPMaterialKey) { - mi->scalingFunction[BLACK] = &ScaleKRKRP; - return mi; - } - if(key == KRPPKRPMaterialKey) { - mi->scalingFunction[WHITE] = &ScaleKRPPKRP; - return mi; - } - else if(key == KRPKRPPMaterialKey) { - mi->scalingFunction[BLACK] = &ScaleKRPKRPP; - return mi; - } - if(key == KBPKBMaterialKey) { - mi->scalingFunction[WHITE] = &ScaleKBPKB; - return mi; - } - if(key == KBKBPMaterialKey) { - mi->scalingFunction[BLACK] = &ScaleKBKBP; - return mi; - } - if(key == KBPKNMaterialKey) { - mi->scalingFunction[WHITE] = &ScaleKBPKN; - return mi; - } - if(key == KNKBPMaterialKey) { - mi->scalingFunction[BLACK] = &ScaleKNKBP; - return mi; - } - if(key == KNPKMaterialKey) { - mi->scalingFunction[WHITE] = &ScaleKNPK; - return mi; + if ((sf = funcs->get(key)) != NULL) + { + mi->scalingFunction[sf->color()] = sf; + return mi; } - if(key == KKNPMaterialKey) { - mi->scalingFunction[BLACK] = &ScaleKKNP; - return mi; + + // 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 (pos.piece_count(BLACK, PAWN) == 0) + { + assert(pos.piece_count(WHITE, PAWN) >= 2); + mi->scalingFunction[WHITE] = &ScaleKPsK; + } + else if (pos.piece_count(WHITE, PAWN) == 0) + { + assert(pos.piece_count(BLACK, PAWN) >= 2); + mi->scalingFunction[BLACK] = &ScaleKKPs; + } + else if (pos.piece_count(WHITE, PAWN) == 1 && pos.piece_count(BLACK, PAWN) == 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; + } } - 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)) { - if(pos.piece_count(BLACK, PAWN) == 0) { - assert(pos.piece_count(WHITE, PAWN) >= 2); - mi->scalingFunction[WHITE] = &ScaleKPsK; - } - else if(pos.piece_count(WHITE, PAWN) == 0) { - assert(pos.piece_count(BLACK, PAWN) >= 2); - mi->scalingFunction[BLACK] = &ScaleKKPs; - } - else if(pos.piece_count(WHITE, PAWN) == 1 && pos.piece_count(BLACK, PAWN) == 1) { - mi->scalingFunction[WHITE] = &ScaleKPKPw; - mi->scalingFunction[BLACK] = &ScaleKPKPb; - } + // Compute the space weight + if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= + 2*QueenValueMidgame + 4*RookValueMidgame + 2*KnightValueMidgame) + { + 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; } - // Evaluate the material balance. - - Color c; - int sign; - Value egValue = Value(0), mgValue = Value(0); - - for(c = WHITE, sign = 1; c <= BLACK; c++, sign = -sign) { - - // 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))) - mi->factor[c] = 0; - else if(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; + // 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, pt1, pt2, pc; + int v, vv, matValue = 0; + + for (c = WHITE, sign = 1; c <= BLACK; c++, sign = -sign) + { + // 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] = SCALE_FACTOR_ZERO; + 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; + // 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); + v = 0; + + // 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 (pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; pt1++) + { + pc = pieceCount[c][pt1]; + if (!pc) + continue; + + vv = LinearCoefficients[pt1]; + + for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; pt2++) + vv += pieceCount[c][pt2] * QuadraticCoefficientsSameColor[pt1][pt2] + + pieceCount[them][pt2] * QuadraticCoefficientsOppositeColor[pt1][pt2]; + + v += pc * vv; } + matValue += sign * v; + } + mi->value = int16_t(matValue / 16); + return mi; +} - // 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; + +/// 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"); +} + +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; + + // 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; + + 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(); +} - } +const string EndgameFunctions::swapColors(const string& keyCode) { - mi->mgValue = int16_t(mgValue); - mi->egValue = int16_t(egValue); + // Build corresponding key for the opposite color: "KBPKN" -> "KNKBP" + size_t idx = keyCode.find("K", 1); + return keyCode.substr(idx) + keyCode.substr(0, idx); +} - return mi; +template +void EndgameFunctions::add(const string& keyCode) { + + typedef typename T::Base F; + + get().insert(pair(buildKey(keyCode), new T(WHITE))); + get().insert(pair(buildKey(swapColors(keyCode)), new T(BLACK))); +} + +template +T* EndgameFunctions::get(Key key) const { + + typename map::const_iterator it(get().find(key)); + return (it != get().end() ? it->second : NULL); }