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movepick.h
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movepick.h
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/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
Copyright (C) 2008 Marco Costalba
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#if !defined MOVEPICK_H_INCLUDED
#define MOVEPICK_H_INCLUDED
////
//// Includes
////
#include "depth.h"
#include "lock.h"
#include "position.h"
////
//// Types
////
/// MovePicker is a class which is used to pick one legal move at a time from
/// the current position. It is initialized with a Position object and a few
/// moves we have reason to believe are good. The most important method is
/// MovePicker::pick_next_move(), which returns a new legal move each time it
/// is called, until there are no legal moves left, when MOVE_NONE is returned.
/// In order to improve the efficiency of the alpha beta algorithm, MovePicker
/// attempts to return the moves which are most likely to be strongest first.
class MovePicker {
public:
enum MovegenPhase {
PH_TT_MOVE, // Transposition table move
PH_MATE_KILLER, // Mate killer from the current ply
PH_GOOD_CAPTURES, // Queen promotions and captures with SEE values >= 0
PH_BAD_CAPTURES, // Queen promotions and captures with SEE values < 0
PH_KILLER_1, // Killer move 1 from the current ply (not used yet).
PH_KILLER_2, // Killer move 2 from the current ply (not used yet).
PH_NONCAPTURES, // Non-captures and underpromotions
PH_EVASIONS, // Check evasions
PH_QCAPTURES, // Captures in quiescence search
PH_QCHECKS, // Checks in quiescence search
PH_STOP
};
MovePicker(const Position& p, bool pvnode, Move ttm, Move mk, Move k1, Move k2, Depth d);
Move get_next_move();
Move get_next_move(Lock &lock);
int number_of_moves() const;
int current_move_score() const;
MovegenPhase current_move_type() const;
Bitboard discovered_check_candidates() const;
static void init_phase_table();
private:
void score_captures();
void score_noncaptures();
void score_evasions();
void score_qcaptures();
Move pick_move_from_list();
int find_best_index();
const Position& pos;
Move ttMove, mateKiller, killer1, killer2;
Bitboard pinned, dc;
MoveStack moves[256], badCaptures[64];
bool pvNode;
Depth depth;
int phaseIndex;
int numOfMoves, numOfBadCaptures;
int movesPicked, badCapturesPicked;
bool finished;
};
////
//// Inline functions
////
/// MovePicker::number_of_moves() simply returns the numOfMoves member
/// variable. It is intended to be used in positions where the side to move
/// is in check, for detecting checkmates or situations where there is only
/// a single reply to check.
inline int MovePicker::number_of_moves() const {
return numOfMoves;
}
/// MovePicker::discovered_check_candidates() returns a bitboard containing
/// all pieces which can possibly give discovered check. This bitboard is
/// computed by the constructor function.
inline Bitboard MovePicker::discovered_check_candidates() const {
return dc;
}
#endif // !defined(MOVEPICK_H_INCLUDED)