/*
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) 2008-2012 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(HISTORY_H_INCLUDED)
#define HISTORY_H_INCLUDED
-////
-//// Includes
-////
-
-#include "depth.h"
-#include "move.h"
-#include "piece.h"
-#include "value.h"
-
-
-////
-//// Types
-////
+#include "types.h"
+#include <cstring>
+#include <algorithm>
/// The History class stores statistics about how often different moves
/// have been successful or unsuccessful during the current search. These
class History {
public:
- History();
void clear();
- void success(Piece p, Square to, Depth d);
- void failure(Piece p, Square to, Depth d);
- int value(Piece p, Square to) const;
- void set_gain(Piece p, Square to, Value delta);
+ Value value(Piece p, Square to) const;
+ void add(Piece p, Square to, Value bonus);
Value gain(Piece p, Square to) const;
+ void update_gain(Piece p, Square to, Value g);
+
+ static const Value MaxValue = Value(2000);
private:
- int history[16][64]; // [piece][square]
- int maxStaticValueDelta[16][64]; // [piece][from_square][to_square]
+ Value history[16][64]; // [piece][to_square]
+ Value maxGains[16][64]; // [piece][to_square]
};
+inline void History::clear() {
+ memset(history, 0, 16 * 64 * sizeof(Value));
+ memset(maxGains, 0, 16 * 64 * sizeof(Value));
+}
-////
-//// Constants and variables
-////
-
-/// HistoryMax controls how often the history counters will be scaled down:
-/// When the history score for a move gets bigger than HistoryMax, all
-/// entries in the table are divided by 2. It is difficult to guess what
-/// the ideal value of this constant is. Scaling down the scores often has
-/// the effect that parts of the search tree which have been searched
-/// recently have a bigger importance for move ordering than the moves which
-/// have been searched a long time ago.
-
-const int HistoryMax = 50000 * ONE_PLY;
-
-
-////
-//// Inline functions
-////
-
-inline int History::value(Piece p, Square to) const {
+inline Value History::value(Piece p, Square to) const {
return history[p][to];
}
+inline void History::add(Piece p, Square to, Value bonus) {
+ if (abs(history[p][to] + bonus) < MaxValue) history[p][to] += bonus;
+}
+
inline Value History::gain(Piece p, Square to) const {
- return Value(maxStaticValueDelta[p][to]);
+ return maxGains[p][to];
+}
+
+inline void History::update_gain(Piece p, Square to, Value g) {
+ maxGains[p][to] = std::max(g, maxGains[p][to] - 1);
}
#endif // !defined(HISTORY_H_INCLUDED)