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) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, 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
#include "movegen.h"
#include "position.h"
-#include "search.h"
#include "types.h"
-/// The Stats struct stores moves statistics. According to the template parameter
-/// the class can store History 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.
-/// 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<typename T, bool CM = false>
-struct Stats {
+/// HistoryStats records how often quiet moves have been successful or unsuccessful
+/// during the current search, and is used for reduction and move ordering decisions.
+struct HistoryStats {
static const Value Max = Value(1 << 28);
- const T* operator[](Piece pc) const { return table[pc]; }
- T* operator[](Piece pc) { return table[pc]; }
+ Value get(Color c, Move m) const { return table[c][from_sq(m)][to_sq(m)]; }
void clear() { std::memset(table, 0, sizeof(table)); }
+ void update(Color c, Move m, Value v) {
- void update(Piece pc, Square to, Move m) { table[pc][to] = m; }
+ Square from = from_sq(m);
+ Square to = to_sq(m);
- void update(Piece pc, Square to, Value v) {
+ const int denom = 324;
- if (abs(int(v)) >= 324)
- return;
+ assert(abs(int(v)) <= denom); // Needed for stability.
- table[pc][to] -= table[pc][to] * abs(int(v)) / (CM ? 936 : 324);
- table[pc][to] += int(v) * 32;
+ table[c][from][to] -= table[c][from][to] * abs(int(v)) / denom;
+ table[c][from][to] += int(v) * 32;
}
private:
- T table[PIECE_NB][SQUARE_NB];
+ Value table[COLOR_NB][SQUARE_NB][SQUARE_NB];
};
-typedef Stats<Move> MoveStats;
-typedef Stats<Value, false> HistoryStats;
-typedef Stats<Value, true> CounterMoveStats;
-typedef Stats<CounterMoveStats> CounterMoveHistoryStats;
-
-struct FromToStats {
- Value get(Color c, Move m) const { return table[c][from_sq(m)][to_sq(m)]; }
- void clear() { std::memset(table, 0, sizeof(table)); }
+/// A template struct, used to generate MoveStats and CounterMoveHistoryStats:
+/// MoveStats store the move that refute a previous one.
+/// CounterMoveHistoryStats is like HistoryStats, but with two consecutive moves.
+/// 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<typename T>
+struct Stats {
+ const T* operator[](Piece pc) const { return table[pc]; }
+ T* operator[](Piece pc) { return table[pc]; }
+ void clear() { std::memset(table, 0, sizeof(table)); }
+ void fill(const Value& v) { std::fill(&table[0][0], &table[PIECE_NB-1][SQUARE_NB-1]+1, v); };
+ void update(Piece pc, Square to, Move m) { table[pc][to] = m; }
+ void update(Piece pc, Square to, Value v) {
- void update(Color c, Move m, Value v)
- {
- if (abs(int(v)) >= 324)
- return;
+ const int denom = 936;
- Square f = from_sq(m);
- Square t = to_sq(m);
+ assert(abs(int(v)) <= denom); // Needed for stability.
- table[c][f][t] -= table[c][f][t] * abs(int(v)) / 324;
- table[c][f][t] += int(v) * 32;
- }
+ table[pc][to] -= table[pc][to] * abs(int(v)) / denom;
+ table[pc][to] += int(v) * 32;
+ }
private:
- Value table[COLOR_NB][SQUARE_NB][SQUARE_NB];
+ T table[PIECE_NB][SQUARE_NB];
};
+typedef Stats<Move> MoveStats;
+typedef Stats<Value> CounterMoveStats;
+typedef Stats<CounterMoveStats> CounterMoveHistoryStats;
+
+
/// 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.
+namespace Search { struct Stack; }
class MovePicker {
public:
MovePicker(const Position&, Move, Depth, Square);
MovePicker(const Position&, Move, Depth, Search::Stack*);
- Move next_move();
- int see_sign() const;
+ Move next_move(bool skipQuiets = false);
private:
template<GenType> void score();
- void generate_next_stage();
- ExtMove* begin() { return moves; }
+ ExtMove* begin() { return cur; }
ExtMove* end() { return endMoves; }
const Position& pos;
Move countermove;
Depth depth;
Move ttMove;
- ExtMove killers[3];
Square recaptureSquare;
Value threshold;
int stage;
- ExtMove* endBadCaptures = moves + MAX_MOVES - 1;
- ExtMove moves[MAX_MOVES], *cur = moves, *endMoves = moves;
+ ExtMove *cur, *endMoves, *endBadCaptures;
+ ExtMove moves[MAX_MOVES];
};
#endif // #ifndef MOVEPICK_H_INCLUDED
projects / stockfish / blobdiff