/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2015-2019 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
-#include "history.h"
+#include <array>
+#include <limits>
+#include <type_traits>
+
+#include "movegen.h"
#include "position.h"
-#include "search.h"
#include "types.h"
-/// MovePicker is a class which is used to pick one pseudo 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::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.
+/// StatsEntry stores the stat table value. It is usually a number but could
+/// be a move or even a nested history. We use a class instead of naked value
+/// to directly call history update operator<<() on the entry so to use stats
+/// tables at caller sites as simple multi-dim arrays.
+template<typename T, int D>
+class StatsEntry {
+
+ T entry;
+
+public:
+ void operator=(const T& v) { entry = v; }
+ T* operator&() { return &entry; }
+ T* operator->() { return &entry; }
+ operator const T&() const { return entry; }
+
+ void operator<<(int bonus) {
+ assert(abs(bonus) <= D); // Ensure range is [-D, D]
+ static_assert(D <= std::numeric_limits<T>::max(), "D overflows T");
+
+ entry += bonus - entry * abs(bonus) / D;
+ assert(abs(entry) <= D);
+ }
+};
+
+/// Stats is a generic N-dimensional array used to store various statistics.
+/// The first template parameter T is the base type of the array, the second
+/// template parameter D limits the range of updates in [-D, D] when we update
+/// values with the << operator, while the last parameters (Size and Sizes)
+/// encode the dimensions of the array.
+template <typename T, int D, int Size, int... Sizes>
+struct Stats : public std::array<Stats<T, D, Sizes...>, Size>
+{
+ typedef Stats<T, D, Size, Sizes...> stats;
+
+ void fill(const T& v) {
+
+ // For standard-layout 'this' points to first struct member
+ assert(std::is_standard_layout<stats>::value);
+
+ typedef StatsEntry<T, D> entry;
+ entry* p = reinterpret_cast<entry*>(this);
+ std::fill(p, p + sizeof(*this) / sizeof(entry), v);
+ }
+};
+
+template <typename T, int D, int Size>
+struct Stats<T, D, Size> : public std::array<StatsEntry<T, D>, Size> {};
+
+/// In stats table, D=0 means that the template parameter is not used
+enum StatsParams { NOT_USED = 0 };
+enum StatsType { NoCaptures, Captures };
+
+/// 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 2 tables (one for each color) indexed by
+/// the move's from and to squares, see www.chessprogramming.org/Butterfly_Boards
+typedef Stats<int16_t, 10692, COLOR_NB, int(SQUARE_NB) * int(SQUARE_NB)> ButterflyHistory;
+
+/// CounterMoveHistory stores counter moves indexed by [piece][to] of the previous
+/// move, see www.chessprogramming.org/Countermove_Heuristic
+typedef Stats<Move, NOT_USED, PIECE_NB, SQUARE_NB> CounterMoveHistory;
+
+/// CapturePieceToHistory is addressed by a move's [piece][to][captured piece type]
+typedef Stats<int16_t, 10692, PIECE_NB, SQUARE_NB, PIECE_TYPE_NB> CapturePieceToHistory;
+
+/// PieceToHistory is like ButterflyHistory but is addressed by a move's [piece][to]
+typedef Stats<int16_t, 29952, PIECE_NB, SQUARE_NB> PieceToHistory;
+
+/// ContinuationHistory is the combined history of a given pair of moves, usually
+/// the current one given a previous one. The nested history table is based on
+/// PieceToHistory instead of ButterflyBoards.
+typedef Stats<PieceToHistory, NOT_USED, PIECE_NB, SQUARE_NB> ContinuationHistory;
+
+
+/// 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 {
- MovePicker& operator=(const MovePicker&); // Silence a warning under MSVC
+ enum PickType { Next, Best };
public:
- MovePicker(const Position&, Move, Depth, const History&, Search::Stack*, Value);
- MovePicker(const Position&, Move, Depth, const History&, Square recaptureSq);
- MovePicker(const Position&, Move, const History&, PieceType parentCapture);
- Move next_move();
+ MovePicker(const MovePicker&) = delete;
+ MovePicker& operator=(const MovePicker&) = delete;
+ MovePicker(const Position&, Move, Value, const CapturePieceToHistory*);
+ MovePicker(const Position&, Move, Depth, const ButterflyHistory*,
+ const CapturePieceToHistory*,
+ const PieceToHistory**,
+ Square);
+ MovePicker(const Position&, Move, Depth, const ButterflyHistory*,
+ const CapturePieceToHistory*,
+ const PieceToHistory**,
+ Move,
+ Move*);
+ Move next_move(bool skipQuiets = false);
private:
- void score_captures();
- void score_noncaptures();
- void score_evasions();
- void go_next_phase();
+ template<PickType T, typename Pred> Move select(Pred);
+ template<GenType> void score();
+ ExtMove* begin() { return cur; }
+ ExtMove* end() { return endMoves; }
const Position& pos;
- const History& H;
- Depth depth;
+ const ButterflyHistory* mainHistory;
+ const CapturePieceToHistory* captureHistory;
+ const PieceToHistory** continuationHistory;
Move ttMove;
- MoveStack killers[2];
+ ExtMove refutations[3], *cur, *endMoves, *endBadCaptures;
+ int stage;
Square recaptureSquare;
- int captureThreshold, phase;
- const uint8_t* phasePtr;
- MoveStack *curMove, *lastMove, *lastNonCapture, *badCaptures;
- MoveStack moves[MAX_MOVES];
+ Value threshold;
+ Depth depth;
+ ExtMove moves[MAX_MOVES];
};
-#endif // !defined(MOVEPICK_H_INCLUDED)
+#endif // #ifndef MOVEPICK_H_INCLUDED
projects / stockfish / blobdiff