subtract_with_carry_01 Class

Generates a random sequence by the floating-point subtract with carry algorithm. Retained for TR1 compatibility. Use subtract_with_carry_engine Class instead.

template<class RealType,
   int W, int S, int R>
   class subtract_with_carry_01 {
   typedef RealType result_type;
   static const int word_size = W;
   static const int short_lag = S;
   static const int long_lag = R;
   explicit subtract_with_carry_01(unsigned long x0);
   template<class Gen>
      subtract_with_carry_01(Gen& gen);
   subtract_with_carry_01(const subtract_with_carry_01& right);
   subtract_with_carry_01(subtract_with_carry_01& right);
   void seed(unsigned long x0 = 19780503UL);
   template<class Gen>
      void seed(Gen& gen);
   result_type min() const;
   result_type max() const;
   result_type operator()();


  • RealType
    The floating-point result type.

  • W
    The W engine parameter.

  • S
    The S engine parameter.

  • R
    The R engine parameter.


The template class decribes a simple engine that produces values of a user-specified floating-point type using the recurrence relation x(i) = (x(i - R) - x(i - S) - cy(i - 1)) mod 1, where cy(i) has the value 2-W if x(i - S) - x(i - R) - cy(i - 1) < 0, otherwise 0. The engine's state is the last R values returned if operator() has been called at least R times, otherwise the M values that have been returned and the last R - M values of the seed.

The template argument RealType must be large enough to hold values with W fraction bits. The values of the template arguments S and R must be greater than 0 and S must be less than R.


Header: <random>

Namespace: std

See Also



subtract_with_carry Class