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c794c8c801
Remove the distinction between the king file and the two neighbours files in the ShelterStrength[] array. Instead we initialize the safety variable in the evaluate_shelter() function with a -10 penalty if our king is on a semi-open file (ie. if our king is on a file without a pawn protection). Also rename shelter_storm() to evaluate_shelter() while there. STC: LLR: 2.96 (-2.94,2.94) [-3.00,1.00] Total: 23153 W: 4795 L: 4677 D: 13681 http://tests.stockfishchess.org/tests/view/5adcb83d0ebc595ec7ff8aa7 LTC: LLR: 2.95 (-2.94,2.94) [-3.00,1.00] Total: 25728 W: 3934 L: 3821 D: 17973 http://tests.stockfishchess.org/tests/view/5adcdcb60ebc595ec7ff8adb See the commit history in PR#1559 for the proof that the committed version is equivalent to the version in the tests above: https://github.com/official-stockfish/Stockfish/pull/1559 Full credit to @protonspring for the renormalized values of the ShelterStrength[] array used for the simplification. Thanks! Bench: 4703935
86 lines
2.8 KiB
C++
86 lines
2.8 KiB
C++
/*
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Stockfish, a UCI chess playing engine derived from Glaurung 2.1
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Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
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Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
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Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
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Stockfish is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Stockfish is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef PAWNS_H_INCLUDED
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#define PAWNS_H_INCLUDED
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#include "misc.h"
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#include "position.h"
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#include "types.h"
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namespace Pawns {
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/// Pawns::Entry contains various information about a pawn structure. A lookup
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/// to the pawn hash table (performed by calling the probe function) returns a
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/// pointer to an Entry object.
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struct Entry {
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Score pawn_score(Color c) const { return scores[c]; }
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Bitboard pawn_attacks(Color c) const { return pawnAttacks[c]; }
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Bitboard passed_pawns(Color c) const { return passedPawns[c]; }
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Bitboard pawn_attacks_span(Color c) const { return pawnAttacksSpan[c]; }
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int weak_unopposed(Color c) const { return weakUnopposed[c]; }
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int pawn_asymmetry() const { return asymmetry; }
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int open_files() const { return openFiles; }
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int semiopen_file(Color c, File f) const {
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return semiopenFiles[c] & (1 << f);
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}
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int pawns_on_same_color_squares(Color c, Square s) const {
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return pawnsOnSquares[c][bool(DarkSquares & s)];
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}
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template<Color Us>
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Score king_safety(const Position& pos, Square ksq) {
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return kingSquares[Us] == ksq && castlingRights[Us] == pos.can_castle(Us)
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? kingSafety[Us] : (kingSafety[Us] = do_king_safety<Us>(pos, ksq));
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}
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template<Color Us>
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Score do_king_safety(const Position& pos, Square ksq);
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template<Color Us>
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Value evaluate_shelter(const Position& pos, Square ksq);
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Key key;
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Score scores[COLOR_NB];
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Bitboard passedPawns[COLOR_NB];
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Bitboard pawnAttacks[COLOR_NB];
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Bitboard pawnAttacksSpan[COLOR_NB];
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Square kingSquares[COLOR_NB];
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Score kingSafety[COLOR_NB];
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int weakUnopposed[COLOR_NB];
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int castlingRights[COLOR_NB];
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int semiopenFiles[COLOR_NB];
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int pawnsOnSquares[COLOR_NB][COLOR_NB]; // [color][light/dark squares]
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int asymmetry;
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int openFiles;
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};
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typedef HashTable<Entry, 16384> Table;
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void init();
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Entry* probe(const Position& pos);
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} // namespace Pawns
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#endif // #ifndef PAWNS_H_INCLUDED
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