/// 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.
+/// 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>
+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 update(Piece pc, Square to, Value v) {
- if (abs(table[pc][to] + v) < Max)
- table[pc][to] += v;
+ if (abs(int(v)) >= 324)
+ return;
+
+ table[pc][to] -= table[pc][to] * abs(int(v)) / (CM ? 512 : 324);
+ table[pc][to] += int(v) * (CM ? 64 : 32);
}
private:
T table[PIECE_NB][SQUARE_NB];
};
-typedef Stats<Value> HistoryStats;
typedef Stats<Move> MovesStats;
-typedef Stats<HistoryStats> CounterMovesHistoryStats;
+typedef Stats<Value, false> HistoryStats;
+typedef Stats<Value, true> CounterMovesStats;
+typedef Stats<CounterMovesStats> CounterMovesHistoryStats;
/// MovePicker class is used to pick one pseudo legal move at a time from the
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, Depth, const HistoryStats&, Square);
+ MovePicker(const Position&, Move, const HistoryStats&, Value);
+ MovePicker(const Position&, Move, Depth, const HistoryStats&, const CounterMovesStats&, Move, Search::Stack*);
- template<bool SpNode> Move next_move();
+ Move next_move();
private:
template<GenType> void score();
const Position& pos;
const HistoryStats& history;
- const CounterMovesHistoryStats& counterMovesHistory;
+ const CounterMovesStats* counterMovesHistory;
Search::Stack* ss;
Move countermove;
Depth depth;
Move ttMove;
ExtMove killers[3];
Square recaptureSquare;
- Value captureThreshold;
+ Value threshold;
int stage;
- ExtMove *endQuiets, *endBadCaptures;
+ ExtMove *endQuiets, *endBadCaptures = moves + MAX_MOVES - 1;
ExtMove moves[MAX_MOVES], *cur = moves, *endMoves = moves;
};