Public Types¶

typedef _RealType input_type
typedef _IntType result_type

Public Member Functions¶

_RealType mean () const
template<class _UniformRandomNumberGenerator > result_type operator() (_UniformRandomNumberGenerator &__urng)
poisson_distribution (const _RealType &__mean=_RealType(1))
void reset ()

Friends¶

template<typename _IntType1 , typename _RealType1 , typename _CharT , typename _Traits > std::basic_ostream< _CharT, _Traits > & operator<< (std::basic_ostream< _CharT, _Traits > &__os, const poisson_distribution< _IntType1, _RealType1 > &__x)
template<typename _IntType1 , typename _RealType1 , typename _CharT , typename _Traits > std::basic_istream< _CharT, _Traits > & operator>> (std::basic_istream< _CharT, _Traits > &__is, poisson_distribution< _IntType1, _RealType1 > &__x)

template<typename _IntType = int, typename _RealType = double> class std::poisson_distribution< _IntType, _RealType >¶

A discrete Poisson random number distribution.

The formula for the Poisson probability mass function is $ p(i) = ac{mean^i}{i!} e^{-mean} $ where $ mean $ is the parameter of the distribution.

Definition at line 1864 of file tr1_impl/random.

template<typename _IntType = int, typename _RealType = double> _RealType std::poisson_distribution< _IntType, _RealType >::mean () const [inline] Gets the distribution parameter mean.¶

Definition at line 1884 of file tr1_impl/random.

template<typename _IntType , typename _RealType > template<class _UniformRandomNumberGenerator > poisson_distribution< _IntType, _RealType >::result_type std::poisson_distribution< _IntType, _RealType >::operator() (_UniformRandomNumberGenerator & __urng) [inline] A rejection algorithm when mean >= 12 and a simple method based upon the multiplication of uniform random variates otherwise. NB: The former is available only if _GLIBCXX_USE_C99_MATH_TR1 is defined.¶

Reference: Devroye, L. 'Non-Uniform Random Variates Generation.' Springer-Verlag, New York, 1986, Ch. X, Sects. 3.3 & 3.4 (+ Errata!).

Definition at line 936 of file random.tcc.

References std::abs(), std::log(), and std::max().

template<typename _IntType = int, typename _RealType = double> template<typename _IntType1 , typename _RealType1 , typename _CharT , typename _Traits > std::basic_ostream<_CharT, _Traits>& operator<< (std::basic_ostream< _CharT, _Traits > & __os, const poisson_distribution< _IntType1, _RealType1 > & __x) [friend] Inserts a poisson_distribution random number distribution __x into the output stream __os.¶

Parameters:

Returns:

template<typename _IntType = int, typename _RealType = double> template<typename _IntType1 , typename _RealType1 , typename _CharT , typename _Traits > std::basic_istream<_CharT, _Traits>& operator>> (std::basic_istream< _CharT, _Traits > & __is, poisson_distribution< _IntType1, _RealType1 > & __x) [friend] Extracts a poisson_distribution random number distribution __x from the input stream __is.¶

Parameters:

Returns: