X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=5e8f75d9cc4b6c2561fdd5b1a5bb784078be323c;hp=845bc90df6e0207deb5cf12c3007ed7a51064bd0;hb=9ca4359f3691305fc5e3306c3084c83557ce09c0;hpb=67375f4693c97fb1321864bb4d143812cd824f9b diff --git a/src/material.cpp b/src/material.cpp index 845bc90d..5e8f75d9 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 @@ -24,10 +24,13 @@ #include #include +#include #include #include "material.h" +using namespace std; + //// //// Local definitions @@ -35,82 +38,140 @@ 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); + + // 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[][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 } }; + + 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 } }; + + 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; + } - Key KNNKMaterialKey, KKNNMaterialKey; + template bool is_KBPsK(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; + } } + //// //// Classes //// - -/// See header for a class description. It is declared here to avoid -/// to include in the header file. +/// 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(); - EndgameEvaluationFunctionBase* getEEF(Key key) const; - EndgameScalingFunctionBase* getESF(Key key, Color* c) const; + ~EndgameFunctions(); + template T* get(Key key) const; private: - void add(Key k, EndgameEvaluationFunctionBase* f); - void add(Key k, Color c, EndgameScalingFunctionBase* f); + template void add(const string& keyCode); - struct ScalingInfo - { - Color col; - EndgameScalingFunctionBase* fun; - }; + 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; - std::map EEFmap; - std::map ESFmap; + // ...and here is the accessing template function + template const map& get() const; }; +// 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; } + //// //// Functions //// +/// MaterialInfoTable c'tor and d'tor, called once by each thread -/// Constructor for the MaterialInfoTable class +MaterialInfoTable::MaterialInfoTable() { -MaterialInfoTable::MaterialInfoTable(unsigned int numOfEntries) { - - size = numOfEntries; - entries = new MaterialInfo[size]; + entries = new MaterialInfo[MaterialTableSize]; 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 " << MaterialTableSize * sizeof(MaterialInfo) + << " bytes for material hash table." << endl; + Application::exit_with_failure(); } - clear(); + memset(entries, 0, MaterialTableSize * sizeof(MaterialInfo)); } - -/// Destructor for the MaterialInfoTable class - MaterialInfoTable::~MaterialInfoTable() { - delete [] entries; 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; + + 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. @@ -121,7 +182,7 @@ void MaterialInfoTable::clear() { MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) { Key key = pos.get_material_key(); - int index = key & (size - 1); + unsigned index = unsigned(key & (MaterialTableSize - 1)); MaterialInfo* mi = entries + index; // If mi->key matches the position's material hash key, it means that we @@ -131,50 +192,38 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) { return mi; // Clear the MaterialInfo object, and set its key - mi->clear(); + memset(mi, 0, sizeof(MaterialInfo)); + mi->factor[WHITE] = mi->factor[BLACK] = uint8_t(SCALE_FACTOR_NORMAL); 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. First we look for a fixed // configuration one, then a generic one if previous search failed. - if ((mi->evaluationFunction = funcs->getEEF(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) >= RookValueEndgame) + if (is_KXK(pos) || is_KXK(pos)) { - mi->evaluationFunction = &EvaluateKXK; + mi->evaluationFunction = is_KXK(pos) ? &EvaluateKXK[WHITE] : &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; - } - else if ( pos.pawns() == EmptyBoardBB - && pos.rooks() == EmptyBoardBB - && pos.queens() == EmptyBoardBB) + + 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. - 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; } } @@ -182,59 +231,49 @@ 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. - Color c; - EndgameScalingFunctionBase* sf; - - if ((sf = funcs->getESF(key, &c)) != NULL) + // 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[c] = sf; + 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_KBPsK(pos)) + mi->scalingFunction[WHITE] = &ScaleKBPsK[WHITE]; + + if (is_KBPsK(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]; + + if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) == 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]; } } @@ -251,10 +290,13 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) { } // Evaluate the material balance - - int sign; - Value egValue = Value(0); - Value mgValue = Value(0); + 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) { @@ -281,103 +323,111 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) { } } - // 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": + // 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 - 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); + if (pieceCount[c][ROOK] >= 1) + matValue -= sign * ((pieceCount[c][ROOK] - 1) * RedundantRookPenalty + pieceCount[c][QUEEN] * RedundantQueenPenalty); + + them = opposite_color(c); + v = 0; - // Redundancy of major pieces, again based on Kaufman's paper: - if (pos.piece_count(c, ROOK) >= 1) + // Second-degree polynomial material imbalance by Tord Romstad + // + // 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. + for (pt1 = PIECE_TYPE_NONE; pt1 <= QUEEN; pt1++) { - Value v = Value((pos.piece_count(c, ROOK) - 1) * 32 + pos.piece_count(c, QUEEN) * 16); - mgValue -= sign * v; - egValue -= sign * v; + pc = pieceCount[c][pt1]; + if (!pc) + continue; + + vv = LinearCoefficients[pt1]; + + for (pt2 = PIECE_TYPE_NONE; pt2 <= pt1; pt2++) + vv += pieceCount[c][pt2] * QuadraticCoefficientsSameColor[pt1][pt2] + + pieceCount[them][pt2] * QuadraticCoefficientsOppositeColor[pt1][pt2]; + + v += pc * vv; } + matValue += sign * v; } - mi->mgValue = int16_t(mgValue); - mi->egValue = int16_t(egValue); + 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. +/// EndgameFunctions member definitions. EndgameFunctions::EndgameFunctions() { - typedef Key ZM[2][8][16]; - const ZM& z = Position::zobMaterial; - - static const Color W = WHITE; - static const Color B = BLACK; - - KNNKMaterialKey = z[W][KNIGHT][1] ^ z[W][KNIGHT][2]; - KKNNMaterialKey = z[B][KNIGHT][1] ^ z[B][KNIGHT][2]; - - add(z[W][PAWN][1], &EvaluateKPK); - add(z[B][PAWN][1], &EvaluateKKP); - - add(z[W][BISHOP][1] ^ z[W][KNIGHT][1], &EvaluateKBNK); - add(z[B][BISHOP][1] ^ z[B][KNIGHT][1], &EvaluateKKBN); - add(z[W][ROOK][1] ^ z[B][PAWN][1], &EvaluateKRKP); - add(z[W][PAWN][1] ^ z[B][ROOK][1], &EvaluateKPKR); - add(z[W][ROOK][1] ^ z[B][BISHOP][1], &EvaluateKRKB); - add(z[W][BISHOP][1] ^ z[B][ROOK][1], &EvaluateKBKR); - add(z[W][ROOK][1] ^ z[B][KNIGHT][1], &EvaluateKRKN); - add(z[W][KNIGHT][1] ^ z[B][ROOK][1], &EvaluateKNKR); - add(z[W][QUEEN][1] ^ z[B][ROOK][1], &EvaluateKQKR); - add(z[W][ROOK][1] ^ z[B][QUEEN][1], &EvaluateKRKQ); - add(z[W][BISHOP][2] ^ z[B][KNIGHT][1], &EvaluateKBBKN); - add(z[W][KNIGHT][1] ^ z[B][BISHOP][2], &EvaluateKNKBB); - - add(z[W][KNIGHT][1] ^ z[W][PAWN][1], W, &ScaleKNPK); - add(z[B][KNIGHT][1] ^ z[B][PAWN][1], B, &ScaleKKNP); - - add(z[W][ROOK][1] ^ z[W][PAWN][1] ^ z[B][ROOK][1] , W, &ScaleKRPKR); - add(z[W][ROOK][1] ^ z[B][ROOK][1] ^ z[B][PAWN][1] , B, &ScaleKRKRP); - add(z[W][BISHOP][1] ^ z[W][PAWN][1] ^ z[B][BISHOP][1], W, &ScaleKBPKB); - add(z[W][BISHOP][1] ^ z[B][BISHOP][1] ^ z[B][PAWN][1] , B, &ScaleKBKBP); - add(z[W][BISHOP][1] ^ z[W][PAWN][1] ^ z[B][KNIGHT][1], W, &ScaleKBPKN); - add(z[W][KNIGHT][1] ^ z[B][BISHOP][1] ^ z[B][PAWN][1] , B, &ScaleKNKBP); - - add(z[W][ROOK][1] ^ z[W][PAWN][1] ^ z[W][PAWN][2] ^ z[B][ROOK][1] ^ z[B][PAWN][1], W, &ScaleKRPPKRP); - add(z[W][ROOK][1] ^ z[W][PAWN][1] ^ z[B][ROOK][1] ^ z[B][PAWN][1] ^ z[B][PAWN][2], B, &ScaleKRPKRPP); + 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"); } -void EndgameFunctions::add(Key k, EndgameEvaluationFunctionBase* f) { +EndgameFunctions::~EndgameFunctions() { - EEFmap.insert(std::pair(k, f)); + 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; } -void EndgameFunctions::add(Key k, Color c, EndgameScalingFunctionBase* f) { +Key EndgameFunctions::buildKey(const string& keyCode) { + + assert(keyCode.length() > 0 && keyCode[0] == 'K'); + assert(keyCode.length() < 8); + + stringstream s; + bool upcase = false; - ScalingInfo s = {c, f}; - ESFmap.insert(std::pair(k, s)); + // 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(), 0).get_material_key(); } -EndgameEvaluationFunctionBase* EndgameFunctions::getEEF(Key key) const { +const string EndgameFunctions::swapColors(const string& keyCode) { - std::map::const_iterator it(EEFmap.find(key)); - return (it != EEFmap.end() ? it->second : NULL); + // Build corresponding key for the opposite color: "KBPKN" -> "KNKBP" + size_t idx = keyCode.find("K", 1); + return keyCode.substr(idx) + keyCode.substr(0, idx); } -EndgameScalingFunctionBase* EndgameFunctions::getESF(Key key, Color* c) const { +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))); +} - std::map::const_iterator it(ESFmap.find(key)); - if (it == ESFmap.end()) - return NULL; +template +T* EndgameFunctions::get(Key key) const { - *c = it->second.col; - return it->second.fun; + typename map::const_iterator it = get().find(key); + return it != get().end() ? it->second : NULL; }