29 Numerics library [numerics]

A negative_­binomial_­distribution random number distribution produces random integers $i\ge 0$ distributed according to the discrete probability function

$$P(i|k,p)=(\frac{k+i-1}{i})\cdot p^k\cdot (1-p{)}^i\text{.}$$

[ Note: This implies that $P(i|k,p)$ is undefined when p == 1.  — end note ]

template<class IntType = int>
  class negative_binomial_distribution {
  public:
    // types
    using result_type = IntType;
    using param_type  = unspecified;

    // constructor and reset functions
    explicit negative_binomial_distribution(IntType k = 1, double p = 0.5);
    explicit negative_binomial_distribution(const param_type& parm);
    void reset();

    // generating functions
    template<class URBG>
      result_type operator()(URBG& g);
    template<class URBG>
      result_type operator()(URBG& g, const param_type& parm);

    // property functions
    IntType k() const;
    double p() const;
    param_type param() const;
    void param(const param_type& parm);
    result_type min() const;
    result_type max() const;
  };