X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=cc8e896a143b46c5cea28dcb893a69550451c64b;hp=10daaeb53ae6df5d3507eda190ca6bb6d99b691a;hb=bfd4421f490e721958a77b8304d8ebcb574a583f;hpb=899b9455d6a5ae64f867ce8f78a02c17858e94e9 diff --git a/src/material.cpp b/src/material.cpp index 10daaeb5..cc8e896a 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) 2008-2009 Marco Costalba 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 @@ -34,89 +37,95 @@ namespace { - const Value BishopPairMidgameBonus = Value(100); - const Value BishopPairEndgameBonus = Value(100); - - Key KNNKMaterialKey, KKNNMaterialKey; - - struct ScalingInfo - { - Color col; - ScalingFunction* fun; - }; - + // 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 } }; + + // 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; } + //// //// Classes //// -class EndgameFunctions { +/// 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(); - EndgameEvaluationFunction* getEEF(Key key); - ScalingInfo getESF(Key key); + ~EndgameFunctions(); + template T* get(Key key) const; private: - void add(Key k, EndgameEvaluationFunction* f); - void add(Key k, Color c, ScalingFunction* f); - - std::map EEFmap; - std::map ESFmap; -}; + template void add(const string& keyCode); + static Key buildKey(const string& keyCode); + static const string swapColors(const string& keyCode); -//// -//// Functions -//// + // Here we store two maps, for evaluate and scaling functions + pair, map > maps; -/// 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. + // Maps accessing functions returning const and non-const references + template const map& get() const { return maps.first; } + template map& get() { return maps.first; } +}; -void MaterialInfo::init() { +// 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; } - typedef Key ZM[2][8][16]; - const ZM& z = Position::zobMaterial; +template<> map& +EndgameFunctions::get() { return maps.second; } - KNNKMaterialKey = z[WHITE][KNIGHT][1] ^ z[WHITE][KNIGHT][2]; - KKNNMaterialKey = z[BLACK][KNIGHT][1] ^ z[BLACK][KNIGHT][2]; -} +//// +//// 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]; 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 [] entries; delete funcs; -} - - -/// MaterialInfoTable::clear() clears a material hash table by setting -/// all entries to 0. - -void MaterialInfoTable::clear() { - - memset(entries, 0, size * sizeof(MaterialInfo)); + delete [] entries; } @@ -126,7 +135,7 @@ 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); @@ -136,77 +145,90 @@ MaterialInfo *MaterialInfoTable::get_material_info(const Position& pos) { // 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; - } - // Let's look if we have a specialized evaluation function for this - // particular material configuration. - if ((mi->evaluationFunction = funcs->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) + && 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.pawns() == EmptyBoardBB + && pos.rooks() == EmptyBoardBB + && pos.queens() == 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.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? // // 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. - ScalingInfo si = funcs->getESF(key); - if (si.fun != NULL) + SF* sf; + + if ((sf = funcs->get(key)) != NULL) { - mi->scalingFunction[si.col] = si.fun; + mi->scalingFunction[sf->color()] = sf; 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] = &ScaleKBPK; + 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] = &ScaleKKBP; + 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] = &ScaleKQKRP; + 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] = &ScaleKRPKQ; + mi->scalingFunction[BLACK] = &ScaleKRPsKQ; if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) == Value(0)) { @@ -222,17 +244,33 @@ MaterialInfo *MaterialInfoTable::get_material_info(const Position& pos) { } 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; } } - // 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); + + mi->spaceWeight = minorPieceCount * minorPieceCount; + } - Color c; + // 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); - Value mgValue = Value(0); + int matValue = 0; for (c = WHITE, sign = 1; c <= BLACK; c++, sign = -sign) { @@ -259,106 +297,109 @@ 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); - // 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 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 (int pt1 = NO_PIECE_TYPE; 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; + 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]; + } } } - - mi->mgValue = int16_t(mgValue); - mi->egValue = int16_t(egValue); + mi->value = int16_t(matValue / 16); return mi; } -/// EndgameFunctions members definition. This helper 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. Being per thread avoids to use locks to access them. +/// 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][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"); + add >("KRPPKRP"); } -void EndgameFunctions::add(Key k, EndgameEvaluationFunction* f) { +EndgameFunctions::~EndgameFunctions() { + + for (map::iterator it = maps.first.begin(); it != maps.first.end(); ++it) + delete (*it).second; - EEFmap.insert(std::pair(k, f)); + for (map::iterator it = maps.second.begin(); it != maps.second.end(); ++it) + delete (*it).second; } -void EndgameFunctions::add(Key k, Color c, ScalingFunction* f) { +Key EndgameFunctions::buildKey(const string& keyCode) { - ScalingInfo s = {c, f}; - ESFmap.insert(std::pair(k, s)); -} + assert(keyCode.length() > 0 && keyCode[0] == 'K'); + assert(keyCode.length() < 8); -EndgameEvaluationFunction* EndgameFunctions::getEEF(Key key) { + stringstream s; + bool upcase = false; - EndgameEvaluationFunction* f = NULL; - std::map::iterator it(EEFmap.find(key)); - if (it != EEFmap.end()) - f = it->second; + // 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; - return f; + 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) { + + // Build corresponding key for the opposite color: "KBPKN" -> "KNKBP" + size_t idx = keyCode.find("K", 1); + return keyCode.substr(idx) + keyCode.substr(0, idx); } -ScalingInfo EndgameFunctions::getESF(Key key) { +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))); +} - ScalingInfo si = {WHITE, NULL}; - std::map::iterator it(ESFmap.find(key)); - if (it != ESFmap.end()) - si = it->second; +template +T* EndgameFunctions::get(Key key) const { - return si; + typename map::const_iterator it(get().find(key)); + return (it != get().end() ? it->second : NULL); }