X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=ffc549ca6962bb637e9d23059bb991a76f792563;hp=b82bb0551a02d4c4775bf78673366cf5195b5d51;hb=94b9c65e09b5d396bebb29b62d9979139b5fbdfa;hpb=79513e3a43f351779837be26bed92221a1402bf5 diff --git a/src/material.cpp b/src/material.cpp index b82bb055..ffc549ca 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 @@ -23,11 +23,13 @@ //// #include +#include #include -#include "lock.h" #include "material.h" +using namespace std; + //// //// Local definitions @@ -35,151 +37,140 @@ namespace { - const Value BishopPairMidgameBonus = Value(100); - const Value BishopPairEndgameBonus = Value(100); - - Key KNNKMaterialKey, KKNNMaterialKey; - - struct ScalingInfo - { - Color col; - ScalingFunction* fun; - }; - - std::map EEFmap; - std::map ESFmap; - - Lock EEFmapLock; - Lock ESFmapLock; - - void add(Key k, EndgameEvaluationFunction* f) { - - EEFmap.insert(std::pair(k, f)); - } - - void add(Key k, Color c, ScalingFunction* f) { - - ScalingInfo s = {c, f}; - ESFmap.insert(std::pair(k, s)); + // 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; } - // STL map are not guaranteed to be thread safe even - // for read-access so we need this two helpers to access them. - EndgameEvaluationFunction* getEEF(Key key) { - - EndgameEvaluationFunction* f = NULL; - - lock_grab(&EEFmapLock); - - std::map::iterator it(EEFmap.find(key)); - if (it != EEFmap.end()) - f = it->second; - - lock_release(&EEFmapLock); - return f; + 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; } - ScalingInfo getESF(Key key) { - - ScalingInfo si = {WHITE, NULL}; - - lock_grab(&ESFmapLock); - - std::map::iterator it(ESFmap.find(key)); - if (it != ESFmap.end()) - si = it->second; - - lock_release(&ESFmapLock); - return si; + 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 +//// 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() { +/// 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. - // Initialize std::map access locks - lock_init(&EEFmapLock, NULL); - lock_init(&ESFmapLock, NULL); +class EndgameFunctions { +public: + EndgameFunctions(); + ~EndgameFunctions(); + template T* get(Key key) const; - typedef Key ZM[2][8][16]; - const ZM& z = Position::zobMaterial; +private: + template void add(const string& keyCode); - static const Color W = WHITE; - static const Color B = BLACK; + static Key buildKey(const string& keyCode); + static const string swapColors(const string& keyCode); - KNNKMaterialKey = z[W][KNIGHT][1] ^ z[W][KNIGHT][2]; - KKNNMaterialKey = z[B][KNIGHT][1] ^ z[B][KNIGHT][2]; + // Here we store two maps, for evaluate and scaling functions... + pair maps; - add(z[W][PAWN][1], &EvaluateKPK); - add(z[B][PAWN][1], &EvaluateKKP); + // ...and here is the accessing template function + template const map& get() const; +}; - 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); +// 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; } - 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); -} +//// +//// Functions +//// -/// Constructor for the MaterialInfoTable class +/// 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; + 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. @@ -187,113 +178,123 @@ 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); + unsigned index = unsigned(key & (size - 1)); 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 mi; // 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 ((mi->evaluationFunction = getEEF(key)) != NULL) + // 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) + 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) + + if ( pos.pieces(PAWN) == EmptyBoardBB + && pos.pieces(ROOK) == EmptyBoardBB + && pos.pieces(QUEEN) == EmptyBoardBB) { - mi->evaluationFunction = &EvaluateKKX; - return mi; + // 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? // - // 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. - ScalingInfo si = getESF(key); - if (si.fun != 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[si.col] = si.fun; + 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]; } } - // 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; - int sign; - Value egValue = Value(0); - Value mgValue = Value(0); + 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, pt1, pt2, pc; + int v, vv, matValue = 0; for (c = WHITE, sign = 1; c <= BLACK; c++, sign = -sign) { @@ -320,30 +321,111 @@ MaterialInfo *MaterialInfoTable::get_material_info(const Position& pos) { } } - // Bishop pair - if (pos.piece_count(c, BISHOP) >= 2) + // 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 = PIECE_TYPE_NONE; pt1 <= QUEEN; pt1++) { - mgValue += sign * BishopPairMidgameBonus; - egValue += sign * BishopPairEndgameBonus; + 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->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) +/// 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[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++) { - Value v = Value((pos.piece_count(c, ROOK) - 1) * 32 + pos.piece_count(c, QUEEN) * 16); - mgValue -= sign * v; - egValue -= sign * v; + 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(); +} - mi->mgValue = int16_t(mgValue); - mi->egValue = int16_t(egValue); - return mi; +const string EndgameFunctions::swapColors(const string& keyCode) { + + // Build corresponding key for the opposite color: "KBPKN" -> "KNKBP" + size_t idx = keyCode.find("K", 1); + return keyCode.substr(idx) + keyCode.substr(0, idx); +} + +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; }