NAME¶

std::poisson_distribution< _IntType, _RealType > -

SYNOPSIS¶

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)"

Detailed Description¶

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.

Member Function Documentation¶

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)¶

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().

Friends And Related Function Documentation¶

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:

Author¶

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