X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=eb271e8c94b6701c7eab1a308a451454f242cd76;hp=3b1ead6dafcd22ed40706b666819e8ad3441d23c;hb=152f3b13b78d014dbc85204d6757e2cdf65e5ecf;hpb=5e906ea10e100cdad2f65d49e8212c14a1d65050 diff --git a/src/material.cpp b/src/material.cpp index 3b1ead6d..eb271e8c 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 +23,12 @@ //// #include +#include #include #include "material.h" +using namespace std; //// //// Local definitions @@ -34,80 +36,78 @@ namespace { - const Value BishopPairMidgameBonus = Value(100); - const Value BishopPairEndgameBonus = Value(100); + // Values modified by Joona Kiiski + const Value BishopPairMidgameBonus = Value(109); + const Value BishopPairEndgameBonus = Value(97); - Key KNNKMaterialKey, KKNNMaterialKey; - - struct ScalingInfo - { - Color col; - ScalingFunction* fun; - }; + // Polynomial material balance parameters + const Value RedundantQueenPenalty = Value(358); + const Value RedundantRookPenalty = Value(536); + const int LinearCoefficients[6] = { 1740, -146, -1246, -197, 206, -7 }; - std::map EEFmap; - std::map ESFmap; + const int QuadraticCoefficientsSameColor[][6] = { + { 0, 0, 0, 0, 0, 0 }, { 31, -4, 0, 0, 0, 0 }, { 14, 267, -21, 0, 0, 0 }, + { 0, 7, -26, 0, 0, 0 }, { -3, -1, 69, 162, 80, 0 }, { 40, 27, 119, 174, -64, -49 } }; - void add(Key k, EndgameEvaluationFunction* f) { - - EEFmap.insert(std::pair(k, f)); - } + const int QuadraticCoefficientsOppositeColor[][6] = { + { 0, 0, 0, 0, 0, 0 }, { -9, 0, 0, 0, 0, 0 }, { 49, 32, 0, 0, 0, 0 }, + { -25, 19, -5, 0, 0, 0 }, { 97, -6, 39, -88, 0, 0 }, { 77, 69, -42, 104, 116, 0 } }; - void add(Key k, Color c, ScalingFunction* f) { - - ScalingInfo s = {c, f}; - ESFmap.insert(std::pair(k, s)); - } + // 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); + Key KNNKMaterialKey, KKNNMaterialKey; } //// -//// 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. +typedef EndgameEvaluationFunctionBase EF; +typedef EndgameScalingFunctionBase SF; -void MaterialInfo::init() { +/// See header for a class description. It is declared here to avoid +/// to include in the header file. - typedef Key ZM[2][8][16]; - const ZM& z = Position::zobMaterial; +class EndgameFunctions { +public: + EndgameFunctions(); + ~EndgameFunctions(); + template T* get(Key key) const; - static const Color W = WHITE; - static const Color B = BLACK; +private: + template void add(const string& keyCode); - KNNKMaterialKey = z[W][KNIGHT][1] ^ z[W][KNIGHT][2]; - KKNNMaterialKey = z[B][KNIGHT][1] ^ z[B][KNIGHT][2]; + static Key buildKey(const string& keyCode); + static const string swapColors(const string& keyCode); - add(z[W][PAWN][1], &EvaluateKPK); - add(z[B][PAWN][1], &EvaluateKKP); + // Here we store two maps, one for evaluate and one for scaling + pair, map > maps; - 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); + // Maps accessing functions for const and non-const references + template const map& get() const { return maps.first; } + template map& get() { return maps.first; } +}; - add(z[W][KNIGHT][1] ^ z[W][PAWN][1], W, &ScaleKNPK); - add(z[B][KNIGHT][1] ^ z[B][PAWN][1], B, &ScaleKKNP); +// 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; } - 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); +template<> map& +EndgameFunctions::get() { return maps.second; } - 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 @@ -116,13 +116,13 @@ 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(); } @@ -130,26 +130,18 @@ MaterialInfoTable::MaterialInfoTable(unsigned int numOfEntries) { MaterialInfoTable::~MaterialInfoTable() { + delete funcs; delete [] entries; } -/// MaterialInfoTable::clear() clears a material hash table by setting -/// all entries to 0. - -void MaterialInfoTable::clear() { - - memset(entries, 0, size * sizeof(MaterialInfo)); -} - - /// MaterialInfoTable::get_material_info() takes a position object as input, /// computes or looks up a MaterialInfo object, and returns a pointer to it. /// If the material configuration is not already present in the table, it /// 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); @@ -157,55 +149,71 @@ MaterialInfo *MaterialInfoTable::get_material_info(const Position& pos) { // 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 + // KNN vs K is a draw. if (key == KNNKMaterialKey || key == KKNNMaterialKey) { - mi->factor[WHITE] = mi->factor[BLACK] = 0; - return mi; + 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 (EEFmap.find(key) != EEFmap.end()) - { - mi->evaluationFunction = EEFmap[key]; + // 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. + 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. + SF* sf; - if (ESFmap.find(key) != ESFmap.end()) + if ((sf = funcs->get(key)) != NULL) { - mi->scalingFunction[ESFmap[key].col] = ESFmap[key].fun; + mi->scalingFunction[sf->color()] = sf; return mi; } @@ -252,12 +260,24 @@ MaterialInfo *MaterialInfoTable::get_material_info(const Position& pos) { } } + // 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; + } + // Evaluate the material balance - Color c; + const int bishopsPair_count[2] = { pos.piece_count(WHITE, BISHOP) > 1, pos.piece_count(BLACK, BISHOP) > 1 }; + 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) { @@ -284,30 +304,119 @@ 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); - - // Redundancy of major pieces, again based on Kaufman's paper: if (pos.piece_count(c, ROOK) >= 1) + matValue -= sign * ((pos.piece_count(c, ROOK) - 1) * RedundantRookPenalty + pos.piece_count(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 (PieceType 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, c2, c3; + c1 = sign * (pt1 != NO_PIECE_TYPE ? pos.piece_count(c, pt1) : bishopsPair_count[c]); + if (!c1) + continue; + + matValue += c1 * LinearCoefficients[pt1]; + + for (PieceType pt2 = NO_PIECE_TYPE; pt2 <= pt1; pt2++) + { + c2 = (pt2 != NO_PIECE_TYPE ? pos.piece_count(c, pt2) : bishopsPair_count[c]); + c3 = (pt2 != NO_PIECE_TYPE ? pos.piece_count(them, pt2) : bishopsPair_count[them]); + matValue += c1 * c2 * QuadraticCoefficientsSameColor[pt1][pt2]; + matValue += c1 * c3 * QuadraticCoefficientsOppositeColor[pt1][pt2]; + } } } - 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 needed +/// because std::map is not guaranteed to be thread-safe even if accessed +/// only for a lookup. + +EndgameFunctions::EndgameFunctions() { + + KNNKMaterialKey = buildKey("KNNK"); + KKNNMaterialKey = buildKey("KKNN"); + + 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) { + + // 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; + + 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); +}