Move Picker

Move Picker Stats /// 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 { 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) { table[pc][to] = m; } void update(Piece pc, Square to, Value v) { if (abs(int(v)) >= 324) return; 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<Move> MoveStats; typedef Stats<Value, false> HistoryStats; typedef Stats<Value, true> CounterMoveStats; typedef Stats<CounterMoveStats> CounterMoveHistoryStats; It is a generic 2-D table indexed by (piece, destination square) ...