/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, 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 <array>
-#include "depth.h"
-#include "history.h"
+#include "movegen.h"
#include "position.h"
+#include "types.h"
+/// StatBoards is a generic 2-dimensional array used to store various statistics
+template<int Size1, int Size2, typename T = int>
+struct StatBoards : public std::array<std::array<T, Size2>, Size1> {
-////
-//// Types
-////
+ void fill(const T& v) {
+ T* p = &(*this)[0][0];
+ std::fill(p, p + sizeof(*this) / sizeof(*p), v);
+ }
+};
-struct SearchStack;
+/// ButterflyBoards are 2 tables (one for each color) indexed by the move's from
+/// and to squares, see chessprogramming.wikispaces.com/Butterfly+Boards
+typedef StatBoards<COLOR_NB, int(SQUARE_NB) * int(SQUARE_NB)> ButterflyBoards;
-/// 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.
+/// PieceToBoards are addressed by a move's [piece][to] information
+typedef StatBoards<PIECE_NB, SQUARE_NB> PieceToBoards;
-class MovePicker {
+/// ButterflyHistory records how often quiet moves have been successful or
+/// unsuccessful during the current search, and is used for reduction and move
+/// ordering decisions. It uses ButterflyBoards as backing store.
+struct ButterflyHistory : public ButterflyBoards {
- MovePicker& operator=(const MovePicker&); // silence a warning under MSVC
+ void update(Color c, Move m, int bonus) {
-public:
- MovePicker(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss = NULL, Value beta = -VALUE_INFINITE);
- Move get_next_move();
- int number_of_evasions() const;
+ const int D = 324;
+ auto& entry = (*this)[c][from_to(m)];
-private:
- void score_captures();
- void score_noncaptures();
- void score_evasions();
- void go_next_phase();
+ assert(abs(bonus) <= D); // Consistency check for below formula
- const Position& pos;
- const History& H;
- Bitboard pinned;
- MoveStack ttMoves[2], killers[2];
- int badCaptureThreshold, phase;
- const uint8_t* phasePtr;
- MoveStack *curMove, *lastMove, *lastGoodNonCapture, *badCaptures;
- MoveStack moves[256];
+ entry += bonus * 32 - entry * abs(bonus) / D;
+
+ assert(abs(entry) <= 32 * D);
+ }
+};
+
+/// PieceToHistory is like ButterflyHistory, but is based on PieceToBoards
+struct PieceToHistory : public PieceToBoards {
+
+ void update(Piece pc, Square to, int bonus) {
+
+ const int D = 936;
+ auto& entry = (*this)[pc][to];
+
+ assert(abs(bonus) <= D); // Consistency check for below formula
+
+ entry += bonus * 32 - entry * abs(bonus) / D;
+
+ assert(abs(entry) <= 32 * D);
+ }
};
+/// CounterMoveHistory stores counter moves indexed by [piece][to] of the previous
+/// move, see chessprogramming.wikispaces.com/Countermove+Heuristic
+typedef StatBoards<PIECE_NB, SQUARE_NB, Move> CounterMoveHistory;
-////
-//// Inline functions
-////
+/// ContinuationHistory is the history of a given pair of moves, usually the
+/// current one given a previous one. History table is based on PieceToBoards
+/// instead of ButterflyBoards.
+typedef StatBoards<PIECE_NB, SQUARE_NB, PieceToHistory> ContinuationHistory;
-/// 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.
-inline int MovePicker::number_of_evasions() const {
- return int(lastMove - moves);
-}
+/// 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.
+
+class MovePicker {
+public:
+ MovePicker(const MovePicker&) = delete;
+ MovePicker& operator=(const MovePicker&) = delete;
+ MovePicker(const Position&, Move, Value);
+ MovePicker(const Position&, Move, Depth, const ButterflyHistory*, const PieceToHistory**, Square);
+ MovePicker(const Position&, Move, Depth, const ButterflyHistory*, const PieceToHistory**, Move, Move*);
+ Move next_move(bool skipQuiets = false);
+
+private:
+ template<GenType> void score();
+ ExtMove* begin() { return cur; }
+ ExtMove* end() { return endMoves; }
+
+ const Position& pos;
+ const ButterflyHistory* mainHistory;
+ const PieceToHistory** contHistory;
+ Move ttMove, countermove, killers[2];
+ ExtMove *cur, *endMoves, *endBadCaptures;
+ int stage;
+ Square recaptureSquare;
+ Value threshold;
+ Depth depth;
+ ExtMove moves[MAX_MOVES];
+};
-#endif // !defined(MOVEPICK_H_INCLUDED)
+#endif // #ifndef MOVEPICK_H_INCLUDED
projects / stockfish / blobdiff