/*
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
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, 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
namespace Material {
/// Material::Entry contains various information about a material configuration.
-/// It contains a material balance evaluation, a function pointer to a special
+/// It contains a material imbalance 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".
+/// 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.
+/// 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; }
+ Score imbalance() const { return make_score(value, value); }
Phase game_phase() const { return gamePhase; }
- bool specialized_eval_exists() const { return evaluationFunction != NULL; }
+ bool specialized_eval_exists() const { return evaluationFunction != nullptr; }
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.
-
+ // 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 may also be a function which should be applied to
+ // the position. For instance, in KBP vs K endgames, the scaling function looks
+ // for 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);
+ ScaleFactor sf = scalingFunction[c] ? (*scalingFunction[c])(pos)
+ : SCALE_FACTOR_NONE;
+ return sf != SCALE_FACTOR_NONE ? sf : ScaleFactor(factor[c]);
}
Key key;
+ const EndgameBase<Value>* evaluationFunction;
+ const EndgameBase<ScaleFactor>* scalingFunction[COLOR_NB]; // Could be one for each
+ // side (e.g. KPKP, KBPsKs)
int16_t value;
uint8_t factor[COLOR_NB];
- EndgameBase<Value>* evaluationFunction;
- EndgameBase<ScaleFactor>* scalingFunction[COLOR_NB];
- Score spaceWeight;
Phase gamePhase;
};
typedef HashTable<Entry, 8192> Table;
-Entry* probe(const Position& pos, Table& entries, Endgames& endgames);
-Phase game_phase(const Position& pos);
+Entry* probe(const Position& pos);
} // namespace Material