Class template exponential_distribution

boost::random::exponential_distribution

Synopsis

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

template<typename RealType = double> 
class exponential_distribution {
public:
  // types
  typedef RealType input_type; 
  typedef RealType result_type;

  // member classes/structs/unions

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

    // construct/copy/destruct
    param_type(RealType = 1.0);

    // public member functions
    RealType lambda() 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 exponential_distribution(RealType = 1.0);
  explicit exponential_distribution(const param_type &);

  // public member functions
  RealType lambda() const;
  RealType min() const;
  RealType 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 exponential_distribution &);
  template<typename CharT, typename Traits> 
    friend std::basic_istream< CharT, Traits > & 
    operator>>(std::basic_istream< CharT, Traits > &, 
               const exponential_distribution &);
  friend bool operator==(const exponential_distribution &, 
                         const exponential_distribution &);
  friend bool operator!=(const exponential_distribution &, 
                         const exponential_distribution &);
};

Description

The exponential distribution is a model of random distribution with a single parameter lambda.

It has

`exponential_distribution` public construct/copy/destruct

```
explicit exponential_distribution(RealType lambda = 1.0);
```
Constructs an exponential_distribution with a given lambda.

Requires: lambda > 0

explicit exponential_distribution(const param_type & param);

Constructs an exponential_distribution from its parameters

`exponential_distribution` public member functions

```
RealType lambda() const;
```
Returns the lambda parameter of the distribution.
```
RealType min() const;
```
Returns the smallest value that the distribution can produce.
```
RealType 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 exponential distribution.
```
template<typename Engine> 
  result_type operator()(Engine & eng, const param_type & param) const;
```
Returns a random variate distributed according to the exponential distribution with parameters specified by param.

`exponential_distribution` friend functions

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

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 exponential_distribution & ed);

Reads the distribution from a std::istream.

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

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

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

Returns true iff the two distributions will produce different sequences of values given equal generators.

Boost C++ Libraries

Class template exponential_distribution

Synopsis

Description

exponential_distribution public construct/copy/destruct

exponential_distribution public member functions

exponential_distribution friend functions

`exponential_distribution` public construct/copy/destruct

`exponential_distribution` public member functions

`exponential_distribution` friend functions