Class template geometric_distribution

boost::random::geometric_distribution

Synopsis

// In header: <boost/random/geometric_distribution.hpp>

template<typename IntType = int, typename RealType = double> 
class geometric_distribution {
public:
  // types
  typedef RealType input_type; 
  typedef IntType  result_type;

  // member classes/structs/unions

  class param_type {
  public:
    // types
    typedef geometric_distribution distribution_type;

    // construct/copy/destruct
    explicit param_type(RealType = 0.5);

    // public member functions
    RealType p() const;

    // friend functions
    template<typename CharT, typename Traits> 
      friend std::basic_ostream< CharT, Traits > & 
      operator<<(std::basic_ostream< CharT, Traits > &, const param_type &);
    template<typename CharT, typename Traits> 
      friend std::basic_istream< CharT, Traits > & 
      operator>>(std::basic_istream< CharT, Traits > &, const param_type &);
    friend bool operator==(const param_type &, const param_type &);
    friend bool operator!=(const param_type &, const param_type &);
  };

  // construct/copy/destruct
  explicit geometric_distribution(const RealType & = 0.5);
  explicit geometric_distribution(const param_type &);

  // public member functions
  RealType p() const;
  IntType min() const;
  IntType max() const;
  param_type param() const;
  void param(const param_type &);
  void reset();
  template<typename Engine> result_type operator()(Engine &) const;
  template<typename Engine> 
    result_type operator()(Engine &, const param_type &) const;

  // friend functions
  template<typename CharT, typename Traits> 
    friend std::basic_ostream< CharT, Traits > & 
    operator<<(std::basic_ostream< CharT, Traits > &, 
               const geometric_distribution &);
  template<typename CharT, typename Traits> 
    friend std::basic_istream< CharT, Traits > & 
    operator>>(std::basic_istream< CharT, Traits > &, 
               const geometric_distribution &);
  friend bool operator==(const geometric_distribution &, 
                         const geometric_distribution &);
  friend bool operator!=(const geometric_distribution &, 
                         const geometric_distribution &);
};

Description

An instantiation of the class template geometric_distribution models a random distribution . The distribution produces positive integers which are the number of bernoulli trials with probability p required to get one that fails.

For the geometric distribution, .

	Warning
	This distribution has been updated to match the C++ standard. Its behavior has changed from the original boost::geometric_distribution. A backwards compatible wrapper is provided in namespace boost.

`geometric_distribution` public construct/copy/destruct

```
explicit geometric_distribution(const RealType & p = 0.5);
```
Contructs a new geometric_distribution with the paramter p.

Requires: 0 < p < 1

explicit geometric_distribution(const param_type & param);

Constructs a new geometric_distribution from its parameters.

`geometric_distribution` public member functions

```
RealType p() const;
```
Returns: the distribution parameter p
```
IntType min() const;
```
Returns the smallest value that the distribution can produce.
```
IntType max() const;
```
Returns the largest value that the distribution can produce.
```
param_type param() const;
```
Returns the parameters of the distribution.
```
void param(const param_type & param);
```
Sets the parameters of the distribution.
```
void reset();
```
Effects: Subsequent uses of the distribution do not depend on values produced by any engine prior to invoking reset.
```
template<typename Engine> result_type operator()(Engine & eng) const;
```
Returns a random variate distributed according to the geometric_distribution.
```
template<typename Engine> 
  result_type operator()(Engine & eng, const param_type & param) const;
```
Returns a random variate distributed according to the geometric distribution with parameters specified by param.

`geometric_distribution` friend functions

template<typename CharT, typename Traits> 
  friend std::basic_ostream< CharT, Traits > & 
  operator<<(std::basic_ostream< CharT, Traits > & os, 
             const geometric_distribution & gd);

Writes the distribution to a std::ostream.

template<typename CharT, typename Traits> 
  friend std::basic_istream< CharT, Traits > & 
  operator>>(std::basic_istream< CharT, Traits > & is, 
             const geometric_distribution & gd);

Reads the distribution from a std::istream.

friend bool operator==(const geometric_distribution & lhs, 
                       const geometric_distribution & rhs);

Returns true if the two distributions will produce identical sequences of values given equal generators.

friend bool operator!=(const geometric_distribution & lhs, 
                       const geometric_distribution & rhs);

Returns true if the two distributions may produce different sequences of values given equal generators.

Boost C++ Libraries