/*
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