mirror of
https://github.com/peterosterlund2/droidfish.git
synced 2025-01-08 08:17:01 +01:00
121 lines
3.7 KiB
C++
121 lines
3.7 KiB
C++
/*
|
|
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
|
|
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
|
|
Copyright (C) 2008-2012 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 <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#if !defined(MATERIAL_H_INCLUDED)
|
|
#define MATERIAL_H_INCLUDED
|
|
|
|
#include "endgame.h"
|
|
#include "misc.h"
|
|
#include "position.h"
|
|
#include "types.h"
|
|
|
|
const int MaterialTableSize = 8192;
|
|
|
|
/// Game phase
|
|
enum Phase {
|
|
PHASE_ENDGAME = 0,
|
|
PHASE_MIDGAME = 128
|
|
};
|
|
|
|
|
|
/// MaterialEntry is a class which 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" for black and white.
|
|
///
|
|
/// 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.
|
|
|
|
class MaterialEntry {
|
|
|
|
friend struct MaterialTable;
|
|
|
|
public:
|
|
Score material_value() const;
|
|
ScaleFactor scale_factor(const Position& pos, Color c) const;
|
|
int space_weight() const;
|
|
Phase game_phase() const;
|
|
bool specialized_eval_exists() const;
|
|
Value evaluate(const Position& pos) const;
|
|
|
|
private:
|
|
Key key;
|
|
int16_t value;
|
|
uint8_t factor[2];
|
|
EndgameBase<Value>* evaluationFunction;
|
|
EndgameBase<ScaleFactor>* scalingFunction[2];
|
|
int spaceWeight;
|
|
Phase gamePhase;
|
|
};
|
|
|
|
|
|
/// The MaterialTable class represents a material hash table. The most important
|
|
/// method is probe(), which returns a pointer to a MaterialEntry object.
|
|
|
|
struct MaterialTable {
|
|
|
|
MaterialEntry* probe(const Position& pos);
|
|
static Phase game_phase(const Position& pos);
|
|
template<Color Us> static int imbalance(const int pieceCount[][8]);
|
|
|
|
HashTable<MaterialEntry, MaterialTableSize> entries;
|
|
Endgames endgames;
|
|
};
|
|
|
|
|
|
/// MaterialEntry::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
|
|
/// to 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
|
|
/// which checks for draws with rook pawns and wrong-colored bishops.
|
|
|
|
inline ScaleFactor MaterialEntry::scale_factor(const Position& pos, Color c) const {
|
|
|
|
if (!scalingFunction[c])
|
|
return ScaleFactor(factor[c]);
|
|
|
|
ScaleFactor sf = (*scalingFunction[c])(pos);
|
|
return sf == SCALE_FACTOR_NONE ? ScaleFactor(factor[c]) : sf;
|
|
}
|
|
|
|
inline Value MaterialEntry::evaluate(const Position& pos) const {
|
|
return (*evaluationFunction)(pos);
|
|
}
|
|
|
|
inline Score MaterialEntry::material_value() const {
|
|
return make_score(value, value);
|
|
}
|
|
|
|
inline int MaterialEntry::space_weight() const {
|
|
return spaceWeight;
|
|
}
|
|
|
|
inline Phase MaterialEntry::game_phase() const {
|
|
return gamePhase;
|
|
}
|
|
|
|
inline bool MaterialEntry::specialized_eval_exists() const {
|
|
return evaluationFunction != NULL;
|
|
}
|
|
|
|
#endif // !defined(MATERIAL_H_INCLUDED)
|