X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=27ea5923b492fc9caeb548a29e8dab6c1369da91;hp=2718300d84474ec650e5e6696de05d9dce8707ae;hb=339bb8a524a0a6af093b383da9f61b31504be9fe;hpb=d0e51bc0f0c77f93323aaa86c9c2485c41d38271 diff --git a/src/material.cpp b/src/material.cpp index 2718300d..27ea5923 100644 --- a/src/material.cpp +++ b/src/material.cpp @@ -1,13 +1,14 @@ /* - Glaurung, a UCI chess playing engine. - Copyright (C) 2004-2008 Tord Romstad + 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 - Glaurung is free software: you can redistribute it and/or modify + Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. - Glaurung is distributed in the hope that it will be useful, + Stockfish is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. @@ -22,9 +23,12 @@ //// #include +#include +#include #include "material.h" +using namespace std; //// //// Local definitions @@ -32,147 +36,100 @@ namespace { - const Value BishopPairMidgameBonus = Value(100); - const Value BishopPairEndgameBonus = Value(100); - - Key KPKMaterialKey, KKPMaterialKey; - Key KBNKMaterialKey, KKBNMaterialKey; - Key KRKPMaterialKey, KPKRMaterialKey; - Key KRKBMaterialKey, KBKRMaterialKey; - Key KRKNMaterialKey, KNKRMaterialKey; - Key KQKRMaterialKey, KRKQMaterialKey; - Key KRPKRMaterialKey, KRKRPMaterialKey; - Key KRPPKRPMaterialKey, KRPKRPPMaterialKey; - Key KNNKMaterialKey, KKNNMaterialKey; - Key KBPKBMaterialKey, KBKBPMaterialKey; - Key KBPKNMaterialKey, KNKBPMaterialKey; - Key KNPKMaterialKey, KKNPMaterialKey; - Key KPKPMaterialKey; - + // Values modified by Joona Kiiski + const Value BishopPairMidgameBonus = Value(109); + const Value BishopPairEndgameBonus = Value(97); + + // 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 } }; + + // 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); + + // Here we store two maps, one for evaluate and one for scaling + pair, map > maps; + + // Maps accessing functions for 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; } + + //// //// Functions //// -/// 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() { - KPKMaterialKey = Position::zobMaterial[WHITE][PAWN][1]; - KKPMaterialKey = Position::zobMaterial[BLACK][PAWN][1]; - KBNKMaterialKey = - Position::zobMaterial[WHITE][BISHOP][1] ^ - Position::zobMaterial[WHITE][KNIGHT][1]; - KKBNMaterialKey = - Position::zobMaterial[BLACK][BISHOP][1] ^ - Position::zobMaterial[BLACK][KNIGHT][1]; - KRKPMaterialKey = - Position::zobMaterial[WHITE][ROOK][1] ^ - Position::zobMaterial[BLACK][PAWN][1]; - KPKRMaterialKey = - Position::zobMaterial[WHITE][PAWN][1] ^ - Position::zobMaterial[BLACK][ROOK][1]; - KRKBMaterialKey = - Position::zobMaterial[WHITE][ROOK][1] ^ - Position::zobMaterial[BLACK][BISHOP][1]; - KBKRMaterialKey = - Position::zobMaterial[WHITE][BISHOP][1] ^ - Position::zobMaterial[BLACK][ROOK][1]; - KRKNMaterialKey = - Position::zobMaterial[WHITE][ROOK][1] ^ - Position::zobMaterial[BLACK][KNIGHT][1]; - KNKRMaterialKey = - Position::zobMaterial[WHITE][KNIGHT][1] ^ - Position::zobMaterial[BLACK][ROOK][1]; - KQKRMaterialKey = - Position::zobMaterial[WHITE][QUEEN][1] ^ - Position::zobMaterial[BLACK][ROOK][1]; - KRKQMaterialKey = - Position::zobMaterial[WHITE][ROOK][1] ^ - Position::zobMaterial[BLACK][QUEEN][1]; - KRPKRMaterialKey = - Position::zobMaterial[WHITE][ROOK][1] ^ - Position::zobMaterial[WHITE][PAWN][1] ^ - Position::zobMaterial[BLACK][ROOK][1]; - KRKRPMaterialKey = - Position::zobMaterial[WHITE][ROOK][1] ^ - Position::zobMaterial[BLACK][ROOK][1] ^ - Position::zobMaterial[BLACK][PAWN][1]; - KRPPKRPMaterialKey = - Position::zobMaterial[WHITE][ROOK][1] ^ - Position::zobMaterial[WHITE][PAWN][1] ^ - Position::zobMaterial[WHITE][PAWN][2] ^ - Position::zobMaterial[BLACK][ROOK][1] ^ - Position::zobMaterial[BLACK][PAWN][1]; - KRPKRPPMaterialKey = - Position::zobMaterial[WHITE][ROOK][1] ^ - Position::zobMaterial[WHITE][PAWN][1] ^ - Position::zobMaterial[BLACK][ROOK][1] ^ - Position::zobMaterial[BLACK][PAWN][1] ^ - Position::zobMaterial[BLACK][PAWN][2]; - KNNKMaterialKey = - Position::zobMaterial[WHITE][KNIGHT][1] ^ - Position::zobMaterial[WHITE][KNIGHT][2]; - KKNNMaterialKey = - Position::zobMaterial[BLACK][KNIGHT][1] ^ - Position::zobMaterial[BLACK][KNIGHT][2]; - KBPKBMaterialKey = - Position::zobMaterial[WHITE][BISHOP][1] ^ - Position::zobMaterial[WHITE][PAWN][1] ^ - Position::zobMaterial[BLACK][BISHOP][1]; - KBKBPMaterialKey = - Position::zobMaterial[WHITE][BISHOP][1] ^ - Position::zobMaterial[BLACK][BISHOP][1] ^ - Position::zobMaterial[BLACK][PAWN][1]; - KBPKNMaterialKey = - Position::zobMaterial[WHITE][BISHOP][1] ^ - Position::zobMaterial[WHITE][PAWN][1] ^ - Position::zobMaterial[BLACK][KNIGHT][1]; - KNKBPMaterialKey = - Position::zobMaterial[WHITE][KNIGHT][1] ^ - Position::zobMaterial[BLACK][BISHOP][1] ^ - Position::zobMaterial[BLACK][PAWN][1]; - KNPKMaterialKey = - Position::zobMaterial[WHITE][KNIGHT][1] ^ - Position::zobMaterial[WHITE][PAWN][1]; - KKNPMaterialKey = - Position::zobMaterial[BLACK][KNIGHT][1] ^ - Position::zobMaterial[BLACK][PAWN][1]; - KPKPMaterialKey = - Position::zobMaterial[WHITE][PAWN][1] ^ - Position::zobMaterial[BLACK][PAWN][1]; -} +/// Constructor for the MaterialInfoTable class -/// Constructor for the MaterialInfoTable class. +MaterialInfoTable::MaterialInfoTable(unsigned int numOfEntries) { -MaterialInfoTable::MaterialInfoTable(unsigned numOfEntries) { size = numOfEntries; entries = new MaterialInfo[size]; - if(entries == NULL) { - std::cerr << "Failed to allocate " << (numOfEntries * sizeof(MaterialInfo)) - << " bytes for material hash table." << std::endl; - exit(EXIT_FAILURE); + funcs = new EndgameFunctions(); + if (!entries || !funcs) + { + cerr << "Failed to allocate " << (numOfEntries * sizeof(MaterialInfo)) + << " bytes for material hash table." << endl; + Application::exit_with_failure(); } - this->clear(); } -/// Destructor for the MaterialInfoTable class. +/// Destructor for the MaterialInfoTable class MaterialInfoTable::~MaterialInfoTable() { - delete [] entries; -} - -/// MaterialInfoTable::clear() clears a material hash table by setting -/// all entries to 0. - -void MaterialInfoTable::clear() { - memset(entries, 0, size * sizeof(MaterialInfo)); + delete funcs; + delete [] entries; } @@ -182,225 +139,271 @@ 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; - } - // Let's look if we have a specialized evaluation function for this - // particular material configuration: - if(key == KPKMaterialKey) { - mi->evaluationFunction = &EvaluateKPK; - return mi; - } - else if(key == KKPMaterialKey) { - mi->evaluationFunction = &EvaluateKKP; - return mi; - } - else if(key == KBNKMaterialKey) { - mi->evaluationFunction = &EvaluateKBNK; - return mi; - } - else if(key == KKBNMaterialKey) { - mi->evaluationFunction = &EvaluateKKBN; - return mi; - } - else if(key == KRKPMaterialKey) { - mi->evaluationFunction = &EvaluateKRKP; - return mi; - } - else if(key == KPKRMaterialKey) { - mi->evaluationFunction = &EvaluateKPKR; - return mi; - } - else if(key == KRKBMaterialKey) { - mi->evaluationFunction = &EvaluateKRKB; - return mi; - } - else if(key == KBKRMaterialKey) { - mi->evaluationFunction = &EvaluateKBKR; - return mi; + // 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) >= RookValueMidgame) + { + mi->evaluationFunction = &EvaluateKXK; + return mi; } - else if(key == KRKNMaterialKey) { - mi->evaluationFunction = &EvaluateKRKN; - return mi; + else if ( pos.non_pawn_material(WHITE) == Value(0) + && pos.piece_count(WHITE, PAWN) == 0 + && pos.non_pawn_material(BLACK) >= RookValueMidgame) + { + mi->evaluationFunction = &EvaluateKKX; + return mi; } - else if(key == KNKRMaterialKey) { - mi->evaluationFunction = &EvaluateKNKR; - return mi; - } - else if(key == KQKRMaterialKey) { - mi->evaluationFunction = &EvaluateKQKR; - return mi; - } - else if(key == KRKQMaterialKey) { - mi->evaluationFunction = &EvaluateKRKQ; - return mi; - } - else if(pos.non_pawn_material(BLACK) == Value(0) && - pos.piece_count(BLACK, PAWN) == 0 && - pos.non_pawn_material(WHITE) >= RookValueEndgame) { - 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) { - mi->evaluationFunction = &EvaluateKKX; - return mi; + else if ( pos.pawns() == EmptyBoardBB + && pos.rooks() == EmptyBoardBB + && pos.queens() == EmptyBoardBB) + { + // 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)); + + 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? + // 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(key == KKNPMaterialKey) { - mi->scalingFunction[BLACK] = &ScaleKKNP; - return mi; + 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)) { - 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; - } + 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; + } } - // Evaluate the material balance. + // 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); - Color c; + mi->spaceWeight = minorPieceCount * minorPieceCount; + } + + // 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; - 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; + int 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] = 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; + // 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); + + // 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. + them = opposite_color(c); + 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]; + } } + } - // 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; + mi->value = int16_t(matValue / 16); + return mi; +} + + +/// 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() { + + 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; + + // 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; + + 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); }