/* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) Copyright (C) 2008-2014 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 the Free Software Foundation, either version 3 of the License, or (at your option) any later version. Stockfish is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ #ifndef MATERIAL_H_INCLUDED #define MATERIAL_H_INCLUDED #include "endgame.h" #include "misc.h" #include "position.h" #include "types.h" namespace Material { /// Material::Entry contains various information about a material configuration. /// It contains a material balance evaluation, a function pointer to a special /// endgame evaluation function (which in most cases is NULL, meaning that the /// standard evaluation function will be used), and "scale factors". /// /// The scale factors are used to scale the evaluation score up or down. /// For instance, in KRB vs KR endgames, the score is scaled down by a factor /// of 4, which will result in scores of absolute value less than one pawn. struct Entry { Score material_value() const { return make_score(value, value); } Score space_weight() const { return spaceWeight; } Phase game_phase() const { return gamePhase; } bool specialized_eval_exists() const { return evaluationFunction != NULL; } Value evaluate(const Position& pos) const { return (*evaluationFunction)(pos); } // scale_factor takes a position and a color as input, and returns a scale factor // for the given color. We have to provide the position in addition to the color, // because the scale factor need not be a constant: It can also be a function // which should be applied to the position. For instance, in KBP vs K endgames, // a scaling function for draws with rook pawns and wrong-colored bishops. ScaleFactor scale_factor(const Position& pos, Color c) const { return !scalingFunction[c] || (*scalingFunction[c])(pos) == SCALE_FACTOR_NONE ? ScaleFactor(factor[c]) : (*scalingFunction[c])(pos); } Key key; int16_t value; uint8_t factor[COLOR_NB]; EndgameBase* evaluationFunction; EndgameBase* scalingFunction[COLOR_NB]; Score spaceWeight; Phase gamePhase; }; typedef HashTable Table; Entry* probe(const Position& pos, Table& entries, Endgames& endgames); Phase game_phase(const Position& pos); } // namespace Material #endif // #ifndef MATERIAL_H_INCLUDED