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https://github.com/official-stockfish/Stockfish.git
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Stefan GeschwentnerandJoona Kiiski
13c11f4048
Introduce a counter move history table which additionally is indexed by the last move's piece and target square. For quiet move ordering use now the sum of standard and counter move history table. STC: LLR: 2.96 (-2.94,2.94) [-1.50,4.50] Total: 4747 W: 1005 L: 885 D: 2857 LTC: LLR: 2.95 (-2.94,2.94) [0.00,6.00] Total: 5726 W: 1001 L: 872 D: 3853 Because of reported low NPS on multi core test STC (7 threads): ELO: 7.26 +-3.3 (95%) LOS: 100.0% Total: 14937 W: 2710 L: 2398 D: 9829 Bench: 7725341 Resolves #282
118 lines
4.0 KiB
C++
118 lines
4.0 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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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 MOVEPICK_H_INCLUDED
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#define MOVEPICK_H_INCLUDED
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#include <algorithm> // For std::max
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#include <cstring> // For std::memset
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#include "movegen.h"
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#include "position.h"
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#include "search.h"
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#include "types.h"
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/// The Stats struct stores moves statistics. According to the template parameter
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/// the class can store History, Gains and Countermoves. History records how often
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/// different moves have been successful or unsuccessful during the current search
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/// and is used for reduction and move ordering decisions. Gains records the move's
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/// best evaluation gain from one ply to the next and is used for pruning decisions.
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/// Countermoves store the move that refute a previous one. Entries are stored
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/// using only the moving piece and destination square, hence two moves with
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/// different origin but same destination and piece will be considered identical.
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template<bool Gain, typename T>
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struct Stats {
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static const Value Max = Value(250);
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const T* operator[](Piece pc) const { return table[pc]; }
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T* operator[](Piece pc) { return table[pc]; }
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void clear() { std::memset(table, 0, sizeof(table)); }
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void update(Piece pc, Square to, Move m) {
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if (m == table[pc][to].first)
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return;
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table[pc][to].second = table[pc][to].first;
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table[pc][to].first = m;
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}
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void update(Piece pc, Square to, Value v) {
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if (Gain)
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table[pc][to] = std::max(v, table[pc][to] - 1);
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else if (abs(table[pc][to] + v) < Max)
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table[pc][to] += v;
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}
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private:
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T table[PIECE_NB][SQUARE_NB];
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};
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typedef Stats< true, Value> GainsStats;
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typedef Stats<false, Value> HistoryStats;
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typedef Stats<false, std::pair<Move, Move> > MovesStats;
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typedef Stats<false, HistoryStats> CounterMovesHistoryStats;
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/// MovePicker class is used to pick one pseudo legal move at a time from the
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/// current position. The most important method is next_move(), which returns a
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/// new pseudo legal move each time it is called, until there are no moves left,
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/// when MOVE_NONE is returned. In order to improve the efficiency of the alpha
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/// beta algorithm, MovePicker attempts to return the moves which are most likely
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/// to get a cut-off first.
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class MovePicker {
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public:
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MovePicker(const MovePicker&) = delete;
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MovePicker& operator=(const MovePicker&) = delete;
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MovePicker(const Position&, Move, Depth, const HistoryStats&, const CounterMovesHistoryStats&, Square);
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MovePicker(const Position&, Move, const HistoryStats&, const CounterMovesHistoryStats&, PieceType);
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MovePicker(const Position&, Move, Depth, const HistoryStats&, const CounterMovesHistoryStats&, Move*, Move*, Search::Stack*);
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template<bool SpNode> Move next_move();
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private:
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template<GenType> void score();
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void generate_next_stage();
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ExtMove* begin() { return moves; }
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ExtMove* end() { return endMoves; }
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const Position& pos;
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const HistoryStats& history;
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const CounterMovesHistoryStats& counterMovesHistory;
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Search::Stack* ss;
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Move* countermoves;
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Move* followupmoves;
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Depth depth;
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Move ttMove;
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ExtMove killers[6];
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Square recaptureSquare;
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Value captureThreshold;
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int stage;
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ExtMove *endQuiets, *endBadCaptures;
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ExtMove moves[MAX_MOVES], *cur = moves, *endMoves = moves;
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};
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#endif // #ifndef MOVEPICK_H_INCLUDED
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