/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2009 Marco Costalba
+ Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-
#if !defined MOVEPICK_H_INCLUDED
#define MOVEPICK_H_INCLUDED
-////
-//// Includes
-////
+#include <algorithm> // For std::max
+#include <cstring> // For memset
-#include "depth.h"
-#include "history.h"
-#include "lock.h"
+#include "movegen.h"
#include "position.h"
+#include "search.h"
+#include "types.h"
-////
-//// Types
-////
+/// The Stats struct stores moves statistics. According to the template parameter
+/// the class can store History, Gains and Refutations statistics. History records
+/// how often different moves have been successful or unsuccessful during the
+/// current search and is used for reduction and move ordering decisions. Gains
+/// records the move's best evaluation gain from one ply to the next and is used
+/// for pruning decisions. Refutations store the move that refute a previous one.
+/// Entries are stored according only to moving piece and destination square, in
+/// particular two moves with different origin but same destination and same piece
+/// will be considered identical.
+template<bool Gain, typename T>
+struct Stats {
-struct SearchStack;
+ static const Value Max = Value(2000);
-/// 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.
+ const T* operator[](Piece p) const { return &table[p][0]; }
+ void clear() { memset(table, 0, sizeof(table)); }
-class MovePicker {
+ void update(Piece p, Square to, Move m) { table[p][to] = m; }
+ void update(Piece p, Square to, Value v) {
- MovePicker& operator=(const MovePicker&); // silence a warning under MSVC
+ if (Gain)
+ table[p][to] = std::max(v, table[p][to] - 1);
-public:
- MovePicker(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss = NULL);
- Move get_next_move();
- Move get_next_move(Lock& lock);
- int number_of_evasions() const;
- Bitboard discovered_check_candidates() const;
+ else if (abs(table[p][to] + v) < Max)
+ table[p][to] += v;
+ }
private:
- void score_captures();
- void score_noncaptures();
- void score_evasions();
- void go_next_phase();
-
- const Position& pos;
- const History& H;
- MoveStack ttMoves[2], killers[2];
- bool finished;
- int phase;
- const uint8_t* phasePtr;
- MoveStack *curMove, *lastMove, *lastBadCapture;
- Bitboard dc, pinned;
- MoveStack moves[256], badCaptures[64];
+ T table[PIECE_NB][SQUARE_NB];
};
+typedef Stats<true, Value> Gains;
+typedef Stats<false, Value> History;
+typedef Stats<false, Move> Refutations;
+
-////
-//// Inline functions
-////
+/// MovePicker class is used to pick one pseudo legal move at a time from the
+/// current position. The most important method is next_move(), which returns a
+/// new pseudo legal move each time it is called, until there are no 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 get a cut-off first.
-/// MovePicker::number_of_evasions() simply returns the number of moves in
-/// evasions phase. 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.
-/// WARNING: It works as long as PH_EVASIONS is the _only_ phase for evasions.
+class MovePicker {
+
+ MovePicker& operator=(const MovePicker&); // Silence a warning under MSVC
-inline int MovePicker::number_of_evasions() const {
- return int(lastMove - moves);
-}
+public:
+ MovePicker(const Position&, Move, Depth, const History&, const Refutations&, Search::Stack*, Value);
+ MovePicker(const Position&, Move, Depth, const History&, Square);
+ MovePicker(const Position&, Move, const History&, PieceType);
+ template<bool SpNode> Move next_move();
-/// MovePicker::discovered_check_candidates() returns a bitboard containing
-/// all pieces which can possibly give discovered check. This bitboard is
-/// computed by the constructor function.
+private:
+ template<GenType> void score();
+ void generate_next();
-inline Bitboard MovePicker::discovered_check_candidates() const {
- return dc;
-}
+ const Position& pos;
+ const History& Hist;
+ Search::Stack* ss;
+ Depth depth;
+ Move ttMove;
+ MoveStack killers[3];
+ Square recaptureSquare;
+ int captureThreshold, phase;
+ MoveStack *cur, *end, *endQuiets, *endBadCaptures;
+ MoveStack moves[MAX_MOVES];
+};
#endif // !defined(MOVEPICK_H_INCLUDED)
projects / stockfish / blobdiff