X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=31550720c05a48de8c0f764dd56860a9d4afc501;hp=2718300d84474ec650e5e6696de05d9dce8707ae;hb=08c464c690e62b874b7d9b34dfabf455820153d6;hpb=760f77872f3b266c16baa7b53e592e9603735479 diff --git a/src/material.cpp b/src/material.cpp index 2718300d..31550720 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) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad - 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. @@ -16,164 +17,110 @@ along with this program. If not, see . */ - -//// -//// Includes -//// - #include +#include +#include #include "material.h" - -//// -//// Local definitions -//// +using namespace std; 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 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 } }; + + typedef EndgameEvaluationFunctionBase EF; + typedef EndgameScalingFunctionBase SF; + typedef map EFMap; + typedef map SFMap; + + // Endgame evaluation and scaling functions accessed direcly and not through + // the function maps because correspond to more then one material hash key. + EvaluationFunction EvaluateKmmKm[] = { EvaluationFunction(WHITE), EvaluationFunction(BLACK) }; + EvaluationFunction EvaluateKXK[] = { EvaluationFunction(WHITE), EvaluationFunction(BLACK) }; + ScalingFunction ScaleKBPsK[] = { ScalingFunction(WHITE), ScalingFunction(BLACK) }; + ScalingFunction ScaleKQKRPs[] = { ScalingFunction(WHITE), ScalingFunction(BLACK) }; + ScalingFunction ScaleKPsK[] = { ScalingFunction(WHITE), ScalingFunction(BLACK) }; + ScalingFunction ScaleKPKP[] = { ScalingFunction(WHITE), ScalingFunction(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; + } + + 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; + } + 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; + } } -//// -//// 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]; -} +/// 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; -/// Constructor for the MaterialInfoTable class. +private: + template void add(const string& keyCode); -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); - } - this->clear(); -} + static Key buildKey(const string& keyCode); + static const string swapColors(const string& keyCode); + // Here we store two maps, for evaluate and scaling functions... + pair maps; -/// Destructor for the MaterialInfoTable class. + // ...and here is the accessing template function + template const map& get() const; +}; -MaterialInfoTable::~MaterialInfoTable() { - delete [] entries; -} +// Explicit specializations of a member function shall be declared in +// the namespace of which the class template is a member. +template<> const EFMap& EndgameFunctions::get() const { return maps.first; } +template<> const SFMap& EndgameFunctions::get() const { return maps.second; } -/// MaterialInfoTable::clear() clears a material hash table by setting -/// all entries to 0. +/// MaterialInfoTable c'tor and d'tor allocate and free the space for EndgameFunctions -void MaterialInfoTable::clear() { - memset(entries, 0, size * sizeof(MaterialInfo)); -} +MaterialInfoTable::MaterialInfoTable() { funcs = new EndgameFunctions(); } +MaterialInfoTable::~MaterialInfoTable() { delete funcs; } /// MaterialInfoTable::get_material_info() takes a position object as input, @@ -182,225 +129,272 @@ 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) 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 - // 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: - 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: - 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; - } - else if(key == KRKNMaterialKey) { - mi->evaluationFunction = &EvaluateKRKN; - return mi; - } - else if(key == KNKRMaterialKey) { - mi->evaluationFunction = &EvaluateKNKR; - return mi; - } - else if(key == KQKRMaterialKey) { - mi->evaluationFunction = &EvaluateKQKR; - 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; + + if (is_KXK(pos)) + { + mi->evaluationFunction = &EvaluateKXK[WHITE]; + 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; + + if (is_KXK(pos)) + { + mi->evaluationFunction = &EvaluateKXK[BLACK]; + 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; + + if (!pos.pieces(PAWN) && !pos.pieces(ROOK) && !pos.pieces(QUEEN)) + { + // 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[WHITE]; + 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 - // are several conflicting applicable scaling functions and we need to - // decide which one to use. - - 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; + // We face problems when there are several conflicting applicable + // scaling functions and we need to decide which one to use. + SF* sf; + + if ((sf = funcs->get(key)) != NULL) + { + mi->scalingFunction[sf->color()] = sf; + 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; + + // 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[WHITE]; + } + else if (pos.piece_count(WHITE, PAWN) == 0) + { + assert(pos.piece_count(BLACK, PAWN) >= 2); + mi->scalingFunction[BLACK] = &ScaleKPsK[BLACK]; + } + 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] = &ScaleKPKP[WHITE]; + mi->scalingFunction[BLACK] = &ScaleKPKP[BLACK]; + } } - if(key == KNKBPMaterialKey) { - mi->scalingFunction[BLACK] = &ScaleKNKBP; - return mi; + + // No pawns makes it difficult to win, even with a material advantage + if (pos.piece_count(WHITE, PAWN) == 0 && npm_w - npm_b <= BishopValueMidgame) + { + mi->factor[WHITE] = + (npm_w == npm_b || npm_w < RookValueMidgame ? 0 : NoPawnsSF[Min(pos.piece_count(WHITE, BISHOP), 2)]); } - if(key == KNPKMaterialKey) { - mi->scalingFunction[WHITE] = &ScaleKNPK; - return mi; + + 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)]); } - if(key == KKNPMaterialKey) { - mi->scalingFunction[BLACK] = &ScaleKKNP; - return mi; + + // Compute the space weight + if (npm_w + npm_b >= 2 * QueenValueMidgame + 4 * RookValueMidgame + 2 * KnightValueMidgame) + { + 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; } - 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 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) } }; + + mi->value = (int16_t)(imbalance(pieceCount) - imbalance(pieceCount)) / 16; + return mi; +} + + +/// MaterialInfoTable::imbalance() calculates imbalance comparing piece count of each +/// piece type for both colors. + +template +int MaterialInfoTable::imbalance(const int pieceCount[][8]) { + + const Color Them = (Us == WHITE ? BLACK : WHITE); + + int pt1, pt2, pc, vv; + int value = 0; + + // 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]; + + // Second-degree polynomial material imbalance by Tord Romstad + for (pt1 = PIECE_TYPE_NONE; pt1 <= QUEEN; pt1++) + { + pc = pieceCount[Us][pt1]; + if (!pc) + continue; + + vv = LinearCoefficients[pt1]; + + for (pt2 = PIECE_TYPE_NONE; pt2 <= pt1; pt2++) + vv += QuadraticCoefficientsSameColor[pt1][pt2] * pieceCount[Us][pt2] + + QuadraticCoefficientsOppositeColor[pt1][pt2] * pieceCount[Them][pt2]; + + value += pc * vv; } + return value; +} - // 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; - } - } - } - // Bishop pair: - if(pos.piece_count(c, BISHOP) >= 2) { - mgValue += sign * BishopPairMidgameBonus; - egValue += sign * BishopPairEndgameBonus; - } +/// 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. + +Phase MaterialInfoTable::game_phase(const Position& pos) { + + Value npm = pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK); + + if (npm >= MidgameLimit) + return PHASE_MIDGAME; + + if (npm <= EndgameLimit) + return PHASE_ENDGAME; + + return Phase(((npm - EndgameLimit) * 128) / (MidgameLimit - EndgameLimit)); +} - // 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 (EFMap::const_iterator it = maps.first.begin(); it != maps.first.end(); ++it) + delete it->second; + + for (SFMap::const_iterator it = maps.second.begin(); it != maps.second.end(); ++it) + delete it->second; +} + +Key EndgameFunctions::buildKey(const string& keyCode) { + + assert(keyCode.length() > 0 && keyCode.length() < 8); + assert(keyCode[0] == 'K'); + + string fen; + 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; + + fen += char(upcase ? toupper(keyCode[i]) : tolower(keyCode[i])); } + fen += char(8 - keyCode.length() + '0'); + fen += "/8/8/8/8/8/8/8 w - -"; + return Position(fen, false, 0).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; + typedef map M; + + const_cast(get()).insert(pair(buildKey(keyCode), new T(WHITE))); + const_cast(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; }