Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
- Copyright (C) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+ Copyright (C) 2015-2018 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
#define MOVEPICK_H_INCLUDED
#include <array>
+#include <limits>
#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>
+template<int Size1, int Size2, typename T = int16_t>
struct StatBoards : public std::array<std::array<T, Size2>, Size1> {
void fill(const T& v) {
T* p = &(*this)[0][0];
std::fill(p, p + sizeof(*this) / sizeof(*p), v);
}
+
+ void update(T& entry, int bonus, const int D) {
+
+ assert(abs(bonus) <= D); // Ensure range is [-32 * D, 32 * D]
+ assert(abs(32 * D) < (std::numeric_limits<T>::max)()); // Ensure we don't overflow
+
+ entry += bonus * 32 - entry * abs(bonus) / D;
+
+ assert(abs(entry) <= 32 * D);
+ }
+};
+
+/// StatCubes is a generic 3-dimensional array used to store various statistics
+template<int Size1, int Size2, int Size3, typename T = int16_t>
+struct StatCubes : public std::array<std::array<std::array<T, Size3>, Size2>, Size1> {
+
+ void fill(const T& v) {
+ T* p = &(*this)[0][0][0];
+ std::fill(p, p + sizeof(*this) / sizeof(*p), v);
+ }
+
+ void update(T& entry, int bonus, const int D, const int W) {
+
+ assert(abs(bonus) <= D); // Ensure range is [-W * D, W * D]
+ assert(abs(W * D) < (std::numeric_limits<T>::max)()); // Ensure we don't overflow
+
+ entry += bonus * W - entry * abs(bonus) / D;
+
+ assert(abs(entry) <= W * D);
+ }
};
/// ButterflyBoards are 2 tables (one for each color) indexed by the move's from
/// PieceToBoards are addressed by a move's [piece][to] information
typedef StatBoards<PIECE_NB, SQUARE_NB> PieceToBoards;
+/// CapturePieceToBoards are addressed by a move's [piece][to][captured piece type] information
+typedef StatCubes<PIECE_NB, SQUARE_NB, PIECE_TYPE_NB> CapturePieceToBoards;
+
/// 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 {
- void update(Color c, Move m, int v) {
-
- const int D = 324;
- auto& entry = (*this)[c][from_to(m)];
-
- assert(abs(v) <= D); // Consistency check for below formula
-
- entry += v * 32 - entry * abs(v) / D;
-
- assert(abs(entry) <= 32 * D);
+ void update(Color c, Move m, int bonus) {
+ StatBoards::update((*this)[c][from_to(m)], bonus, 324);
}
};
/// PieceToHistory is like ButterflyHistory, but is based on PieceToBoards
struct PieceToHistory : public PieceToBoards {
- void update(Piece pc, Square to, int v) {
-
- const int D = 936;
- auto& entry = (*this)[pc][to];
-
- assert(abs(v) <= D); // Consistency check for below formula
+ void update(Piece pc, Square to, int bonus) {
+ StatBoards::update((*this)[pc][to], bonus, 936);
+ }
+};
- entry += v * 32 - entry * abs(v) / D;
+/// CapturePieceToHistory is like PieceToHistory, but is based on CapturePieceToBoards
+struct CapturePieceToHistory : public CapturePieceToBoards {
- assert(abs(entry) <= 32 * D);
+ void update(Piece pc, Square to, PieceType captured, int bonus) {
+ StatCubes::update((*this)[pc][to][captured], bonus, 324, 2);
}
};
-/// CounterMoveStat stores counter moves indexed by [piece][to] of the previous
+/// 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> CounterMoveStat;
+typedef StatBoards<PIECE_NB, SQUARE_NB, Move> CounterMoveHistory;
-/// CounterMoveHistoryStat is like CounterMoveStat but instead of a move it
-/// stores a full history (based on PieceTo boards instead of ButterflyBoards).
-typedef StatBoards<PIECE_NB, SQUARE_NB, PieceToHistory> CounterMoveHistoryStat;
+/// 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 class is used to pick one pseudo legal move at a time from the
/// 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.
-namespace Search { struct Stack; }
class MovePicker {
public:
MovePicker(const MovePicker&) = delete;
MovePicker& operator=(const MovePicker&) = delete;
-
- MovePicker(const Position&, Move, Value);
- MovePicker(const Position&, Move, Depth, Square);
- MovePicker(const Position&, Move, Depth, Search::Stack*);
-
+ MovePicker(const Position&, Move, Value, const CapturePieceToHistory*);
+ MovePicker(const Position&, Move, Depth, const ButterflyHistory*, const CapturePieceToHistory*, Square);
+ MovePicker(const Position&, Move, Depth, const ButterflyHistory*, const CapturePieceToHistory*, const PieceToHistory**, Move, Move*);
Move next_move(bool skipQuiets = false);
private:
ExtMove* end() { return endMoves; }
const Position& pos;
- const Search::Stack* ss;
- Move killers[2];
- Move countermove;
- Depth depth;
- Move ttMove;
+ const ButterflyHistory* mainHistory;
+ const CapturePieceToHistory* captureHistory;
+ const PieceToHistory** contHistory;
+ Move ttMove, countermove, killers[2];
+ ExtMove *cur, *endMoves, *endBadCaptures;
+ int stage;
Square recaptureSquare;
Value threshold;
- int stage;
- ExtMove *cur, *endMoves, *endBadCaptures;
+ Depth depth;
ExtMove moves[MAX_MOVES];
};