X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=f0ee5f682d02cada44957745849684613f3e4196;hp=c1c3c3c27545653737f2865ef193d04ef8f44b55;hb=6b7efa0cd14b73416c9030462f79a02bbfc7ad2c;hpb=27619830d428693b4871ce58770705b30ba84c99 diff --git a/src/material.cpp b/src/material.cpp index c1c3c3c2..f0ee5f68 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) 2008-2009 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 @@ -23,13 +23,13 @@ //// #include -#include #include #include #include "material.h" -using std::string; +using namespace std; + //// //// Local definitions @@ -37,83 +37,118 @@ using std::string; namespace { - const Value BishopPairMidgameBonus = Value(109); - const Value BishopPairEndgameBonus = Value(97); + // 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 } }; - Key KNNKMaterialKey, KKNNMaterialKey; + // 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 //// - -/// 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(const string& keyCode, EndgameEvaluationFunctionBase* f); - void add(const string& keyCode, Color c, EndgameScalingFunctionBase* f); - Key buildKey(const string& keyCode); + 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, map > maps; - std::map EEFmap; - std::map ESFmap; + // Maps accessing functions returning const and non-const references + template const map& get() const { return maps.first; } + template map& get() { return maps.first; } }; +// 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; } + +template<> map& +EndgameFunctions::get() { return maps.second; } + //// //// 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; + 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; + 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; + else 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. @@ -137,42 +172,37 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) { 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. 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) + && 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) + else 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) @@ -186,41 +216,43 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) { // 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. - Color c; - EndgameScalingFunctionBase* sf; + SF* sf; - if ((sf = funcs->getESF(key, &c)) != NULL) + if ((sf = funcs->get(key)) != NULL) { - mi->scalingFunction[c] = sf; + 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)) { @@ -236,6 +268,8 @@ 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; } @@ -254,10 +288,13 @@ 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) { @@ -267,7 +304,7 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) { { if ( pos.non_pawn_material(c) == pos.non_pawn_material(opposite_color(c)) || pos.non_pawn_material(c) < RookValueMidgame) - mi->factor[c] = 0; + mi->factor[c] = SCALE_FACTOR_ZERO; else { switch (pos.piece_count(c, BISHOP)) { @@ -284,73 +321,68 @@ 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); - // Redundancy of major pieces, again based on Kaufman's paper: - if (pos.piece_count(c, ROOK) >= 1) + 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 = 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; + pc = pieceCount[c][pt1]; + if (!pc) + continue; + + vv = LinearCoefficients[pt1]; + + for (pt2 = NO_PIECE_TYPE; 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() { - KNNKMaterialKey = buildKey("KNNK"); - KKNNMaterialKey = buildKey("KKNN"); - - add("KPK", &EvaluateKPK); - add("KKP", &EvaluateKKP); - add("KBNK", &EvaluateKBNK); - add("KKBN", &EvaluateKKBN); - add("KRKP", &EvaluateKRKP); - add("KPKR", &EvaluateKPKR); - add("KRKB", &EvaluateKRKB); - add("KBKR", &EvaluateKBKR); - add("KRKN", &EvaluateKRKN); - add("KNKR", &EvaluateKNKR); - add("KQKR", &EvaluateKQKR); - add("KRKQ", &EvaluateKRKQ); - add("KBBKN", &EvaluateKBBKN); - add("KNKBB", &EvaluateKNKBB); - - add("KNPK", WHITE, &ScaleKNPK); - add("KKNP", BLACK, &ScaleKKNP); - add("KRPKR", WHITE, &ScaleKRPKR); - add("KRKRP", BLACK, &ScaleKRKRP); - add("KBPKB", WHITE, &ScaleKBPKB); - add("KBKBP", BLACK, &ScaleKBKBP); - add("KBPPKB", WHITE, &ScaleKBPPKB); - add("KBKBPP", BLACK, &ScaleKBKBPP); - add("KBPKN", WHITE, &ScaleKBPKN); - add("KNKBP", BLACK, &ScaleKNKBP); - add("KRPPKRP", WHITE, &ScaleKRPPKRP); - add("KRPKRPP", BLACK, &ScaleKRPKRPP); - add("KRPPKRP", WHITE, &ScaleKRPPKRP); - add("KRPKRPP", BLACK, &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"); +} + +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) { @@ -358,11 +390,11 @@ Key EndgameFunctions::buildKey(const string& keyCode) { assert(keyCode.length() > 0 && keyCode[0] == 'K'); assert(keyCode.length() < 8); - std::stringstream s; + 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. + // 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') @@ -374,29 +406,25 @@ Key EndgameFunctions::buildKey(const string& keyCode) { return Position(s.str()).get_material_key(); } -void EndgameFunctions::add(const string& keyCode, EndgameEvaluationFunctionBase* f) { +const string EndgameFunctions::swapColors(const string& keyCode) { - EEFmap.insert(std::pair(buildKey(keyCode), f)); + // Build corresponding key for the opposite color: "KBPKN" -> "KNKBP" + size_t idx = keyCode.find("K", 1); + return keyCode.substr(idx) + keyCode.substr(0, idx); } -void EndgameFunctions::add(const string& keyCode, Color c, EndgameScalingFunctionBase* f) { - - ScalingInfo s = {c, f}; - ESFmap.insert(std::pair(buildKey(keyCode), s)); -} +template +void EndgameFunctions::add(const string& keyCode) { -EndgameEvaluationFunctionBase* EndgameFunctions::getEEF(Key key) const { + typedef typename T::Base F; - std::map::const_iterator it(EEFmap.find(key)); - return (it != EEFmap.end() ? it->second : NULL); + get().insert(pair(buildKey(keyCode), new T(WHITE))); + get().insert(pair(buildKey(swapColors(keyCode)), new T(BLACK))); } -EndgameScalingFunctionBase* EndgameFunctions::getESF(Key key, Color* c) const { - - 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); }