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| 96 | pmbaty | 1 | /* |
| 2 | Stockfish, a UCI chess playing engine derived from Glaurung 2.1 |
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| 3 | Copyright (C) 2004-2008 Tord Romstad (Glaurung author) |
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| 4 | Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad |
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| 5 | Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad |
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| 6 | |||
| 7 | Stockfish is free software: you can redistribute it and/or modify |
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| 8 | it under the terms of the GNU General Public License as published by |
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| 9 | the Free Software Foundation, either version 3 of the License, or |
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| 10 | (at your option) any later version. |
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| 11 | |||
| 12 | Stockfish is distributed in the hope that it will be useful, |
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| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 15 | GNU General Public License for more details. |
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| 16 | |||
| 17 | You should have received a copy of the GNU General Public License |
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| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. |
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| 19 | */ |
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| 20 | |||
| 21 | #ifndef MATERIAL_H_INCLUDED |
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| 22 | #define MATERIAL_H_INCLUDED |
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| 23 | |||
| 24 | #include "endgame.h" |
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| 25 | #include "misc.h" |
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| 26 | #include "position.h" |
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| 27 | #include "types.h" |
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| 28 | |||
| 29 | namespace Material { |
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| 30 | |||
| 31 | /// Material::Entry contains various information about a material configuration. |
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| 32 | /// It contains a material imbalance evaluation, a function pointer to a special |
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| 33 | /// endgame evaluation function (which in most cases is NULL, meaning that the |
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| 34 | /// standard evaluation function will be used), and scale factors. |
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| 35 | /// |
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| 36 | /// The scale factors are used to scale the evaluation score up or down. For |
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| 37 | /// instance, in KRB vs KR endgames, the score is scaled down by a factor of 4, |
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| 38 | /// which will result in scores of absolute value less than one pawn. |
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| 39 | |||
| 40 | struct Entry { |
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| 41 | |||
| 42 | Score imbalance() const { return make_score(value, value); } |
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| 43 | Phase game_phase() const { return gamePhase; } |
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| 44 | bool specialized_eval_exists() const { return evaluationFunction != nullptr; } |
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| 45 | Value evaluate(const Position& pos) const { return (*evaluationFunction)(pos); } |
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| 46 | |||
| 47 | // scale_factor takes a position and a color as input and returns a scale factor |
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| 48 | // for the given color. We have to provide the position in addition to the color |
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| 49 | // because the scale factor may also be a function which should be applied to |
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| 50 | // the position. For instance, in KBP vs K endgames, the scaling function looks |
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| 51 | // for rook pawns and wrong-colored bishops. |
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| 52 | ScaleFactor scale_factor(const Position& pos, Color c) const { |
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| 154 | pmbaty | 53 | ScaleFactor sf = scalingFunction[c] ? (*scalingFunction[c])(pos) |
| 54 | : SCALE_FACTOR_NONE; |
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| 55 | return sf != SCALE_FACTOR_NONE ? sf : ScaleFactor(factor[c]); |
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| 96 | pmbaty | 56 | } |
| 57 | |||
| 58 | Key key; |
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| 59 | int16_t value; |
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| 60 | uint8_t factor[COLOR_NB]; |
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| 61 | EndgameBase<Value>* evaluationFunction; |
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| 62 | EndgameBase<ScaleFactor>* scalingFunction[COLOR_NB]; // Could be one for each |
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| 63 | // side (e.g. KPKP, KBPsKs) |
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| 64 | Phase gamePhase; |
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| 65 | }; |
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| 66 | |||
| 67 | typedef HashTable<Entry, 8192> Table; |
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| 68 | |||
| 69 | Entry* probe(const Position& pos); |
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| 70 | |||
| 71 | } // namespace Material |
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| 72 | |||
| 73 | #endif // #ifndef MATERIAL_H_INCLUDED |