std::poisson_distribution(3)std::poisson_distribution(3)NAMEstd::poisson_distribution-
A discrete Poisson random number distribution.
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) [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().
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:
__os An output stream.
__x A poisson_distribution random number distribution.
Returns:
The output stream with the state of __x inserted or in an error
state.
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:
__is An input stream.
__x A poisson_distribution random number generator engine.
Returns:
The input stream with __x extracted or in an error state.
Author
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libstdc++ 22 Nov 2013 std::poisson_distribution(3)
