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
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 <algorithm> // For std::max
+#include <cstring> // For std::memset
#include "movegen.h"
#include "position.h"
/// The Stats struct stores moves statistics. According to the template parameter
-/// the class can store History, Gains and Countermoves. History records how often
+/// 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. Gains records the move's
-/// best evaluation gain from one ply to the next and is used for pruning decisions.
+/// 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<bool Gain, typename T>
+template<typename T, bool CM = false>
struct Stats {
- static const Value Max = Value(250);
+ static const Value Max = Value(1 << 28);
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 update(Piece pc, Square to, Move m) {
-
- if (m != table[pc][to])
- table[pc][to] = m;
- }
+ void update(Piece pc, Square to, Move m) { table[pc][to] = m; }
void update(Piece pc, Square to, Value v) {
- if (Gain)
- table[pc][to] = std::max(v, table[pc][to] - 1);
+ if (abs(int(v)) >= 324)
+ return;
- else if (abs(table[pc][to] + v) < Max)
- table[pc][to] += v;
+ table[pc][to] -= table[pc][to] * abs(int(v)) / (CM ? 936 : 324);
+ table[pc][to] += int(v) * 32;
}
private:
T table[PIECE_NB][SQUARE_NB];
};
-typedef Stats< true, Value> GainsStats;
-typedef Stats<false, Value> HistoryStats;
-typedef Stats<false, Move> MovesStats;
-typedef Stats<false, HistoryStats> CounterMovesHistoryStats;
+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)); }
+
+ void update(Color c, Move m, Value v)
+ {
+ if (abs(int(v)) >= 324)
+ return;
+ Square f = from_sq(m);
+ Square t = to_sq(m);
+
+ table[c][f][t] -= table[c][f][t] * abs(int(v)) / 324;
+ table[c][f][t] += int(v) * 32;
+ }
+
+private:
+ Value table[COLOR_NB][SQUARE_NB][SQUARE_NB];
+};
/// 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
MovePicker(const MovePicker&) = delete;
MovePicker& operator=(const MovePicker&) = delete;
- MovePicker(const Position&, Move, Depth, const HistoryStats&, const CounterMovesHistoryStats&, Square);
- MovePicker(const Position&, Move, const HistoryStats&, const CounterMovesHistoryStats&, PieceType);
- MovePicker(const Position&, Move, Depth, const HistoryStats&, const CounterMovesHistoryStats&, Move, Search::Stack*);
+ MovePicker(const Position&, Move, Value);
+ MovePicker(const Position&, Move, Depth, Square);
+ MovePicker(const Position&, Move, Depth, Search::Stack*);
- template<bool SpNode> Move next_move();
+ Move next_move();
private:
template<GenType> void score();
ExtMove* end() { return endMoves; }
const Position& pos;
- const HistoryStats& history;
- const CounterMovesHistoryStats& counterMovesHistory;
- Search::Stack* ss;
+ const Search::Stack* ss;
Move countermove;
Depth depth;
Move ttMove;
ExtMove killers[3];
Square recaptureSquare;
- Value captureThreshold;
+ Value threshold;
int stage;
- ExtMove *endQuiets, *endBadCaptures;
+ ExtMove* endBadCaptures = moves + MAX_MOVES - 1;
ExtMove moves[MAX_MOVES], *cur = moves, *endMoves = moves;
};