/*
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) 2008-2015 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
+#ifndef MOVEPICK_H_INCLUDED
#define MOVEPICK_H_INCLUDED
-////
-//// Includes
-////
+#include <algorithm> // For std::max
+#include <cstring> // For std::memset
-#include "depth.h"
-#include "history.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 Countermoves. 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.
+/// Countermoves store the move that refute a previous one. Entries are stored
+/// using only the moving piece and destination square, hence two moves with
+/// different origin but same destination and piece will be considered identical.
+template<bool Gain, typename T>
+struct Stats {
-struct SearchStack;
+ static const Value Max = Value(250);
-/// 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 pc) const { return table[pc]; }
+ void clear() { std::memset(table, 0, sizeof(table)); }
-class MovePicker {
+ void update(Piece pc, Square to, Move m) {
- MovePicker& operator=(const MovePicker&); // silence a warning under MSVC
+ if (m == table[pc][to].first)
+ return;
-public:
- MovePicker(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss = NULL);
- Move get_next_move();
- int number_of_evasions() const;
+ table[pc][to].second = table[pc][to].first;
+ table[pc][to].first = m;
+ }
-private:
- void score_captures();
- void score_noncaptures();
- void score_evasions_or_checks();
- void go_next_phase();
+ void update(Piece pc, Square to, Value v) {
- const Position& pos;
- const History& H;
- MoveStack ttMoves[2], killers[2];
- int phase;
- const uint8_t* phasePtr;
- MoveStack *curMove, *lastMove, *lastBadCapture;
- Bitboard pinned;
- MoveStack moves[256], badCaptures[64];
+ if (Gain)
+ table[pc][to] = std::max(v, table[pc][to] - 1);
+
+ else if (abs(table[pc][to] + v) < Max)
+ table[pc][to] += v;
+ }
+
+private:
+ T table[PIECE_NB][SQUARE_NB];
};
+typedef Stats< true, Value> GainsStats;
+typedef Stats<false, Value> HistoryStats;
+typedef Stats<false, std::pair<Move, Move> > MovesStats;
-////
-//// Inline functions
-////
-/// 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.
+/// 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.
-inline int MovePicker::number_of_evasions() const {
- return int(lastMove - moves);
-}
+class MovePicker {
+public:
+ MovePicker(const MovePicker&) = delete;
+ MovePicker& operator=(const MovePicker&) = delete;
+
+ MovePicker(const Position&, Move, Depth, const HistoryStats&, Square);
+ MovePicker(const Position&, Move, const HistoryStats&, PieceType);
+ MovePicker(const Position&, Move, Depth, const HistoryStats&, Move*, Move*, Search::Stack*);
+
+ template<bool SpNode> Move next_move();
+
+private:
+ template<GenType> void score();
+ void generate_next_stage();
+
+ const Position& pos;
+ const HistoryStats& history;
+ Search::Stack* ss;
+ Move* countermoves;
+ Move* followupmoves;
+ Depth depth;
+ Move ttMove;
+ ExtMove killers[6];
+ Square recaptureSquare;
+ Value captureThreshold;
+ int stage;
+ ExtMove *cur, *end, *endQuiets, *endBadCaptures;
+ ExtMove moves[MAX_MOVES];
+};
-#endif // !defined(MOVEPICK_H_INCLUDED)
+#endif // #ifndef MOVEPICK_H_INCLUDED
projects / stockfish / blobdiff