2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad
6 Stockfish is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 Stockfish is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
20 #ifndef MATERIAL_H_INCLUDED
21 #define MATERIAL_H_INCLUDED
30 /// Material::Entry contains various information about a material configuration.
31 /// It contains a material balance evaluation, a function pointer to a special
32 /// endgame evaluation function (which in most cases is NULL, meaning that the
33 /// standard evaluation function will be used), and "scale factors".
35 /// The scale factors are used to scale the evaluation score up or down.
36 /// For instance, in KRB vs KR endgames, the score is scaled down by a factor
37 /// of 4, which will result in scores of absolute value less than one pawn.
41 Score material_value() const { return make_score(value, value); }
42 Score space_weight() const { return spaceWeight; }
43 Phase game_phase() const { return gamePhase; }
44 bool specialized_eval_exists() const { return evaluationFunction != NULL; }
45 Value evaluate(const Position& pos) const { return (*evaluationFunction)(pos); }
46 ScaleFactor scale_factor(const Position& pos, Color c) const;
50 uint8_t factor[COLOR_NB];
51 EndgameBase<Value>* evaluationFunction;
52 EndgameBase<ScaleFactor>* scalingFunction[COLOR_NB];
57 typedef HashTable<Entry, 8192> Table;
59 Entry* probe(const Position& pos, Table& entries, Endgames& endgames);
60 Phase game_phase(const Position& pos);
62 /// Material::scale_factor takes a position and a color as input, and
63 /// returns a scale factor for the given color. We have to provide the
64 /// position in addition to the color, because the scale factor need not
65 /// be a constant: It can also be a function which should be applied to
66 /// the position. For instance, in KBP vs K endgames, a scaling function
67 /// which checks for draws with rook pawns and wrong-colored bishops.
69 inline ScaleFactor Entry::scale_factor(const Position& pos, Color c) const {
71 return !scalingFunction[c] || (*scalingFunction[c])(pos) == SCALE_FACTOR_NONE
72 ? ScaleFactor(factor[c]) : (*scalingFunction[c])(pos);
77 #endif // #ifndef MATERIAL_H_INCLUDED