std::poisson_distribution< _IntTypestd::poisson_distribution< _IntType >(3cxx)
NAME
std::poisson_distribution< _IntType > - A discrete Poisson random
number distribution.
SYNOPSIS
Classes
struct param_type
Public Types
typedef _IntType result_type
Public Member Functions
poisson_distribution (const param_type &__p)
poisson_distribution (double __mean)
template<typename _ForwardIterator , typename
_UniformRandomNumberGenerator > void __generate (_ForwardIterator
__f, _ForwardIterator __t, _UniformRandomNumberGenerator &__urng)
template<typename _ForwardIterator , typename
_UniformRandomNumberGenerator > void __generate (_ForwardIterator
__f, _ForwardIterator __t, _UniformRandomNumberGenerator &__urng,
const param_type &__p)
template<typename _UniformRandomNumberGenerator > void __generate
(result_type *__f, result_type *__t, _UniformRandomNumberGenerator
&__urng, const param_type &__p)
result_type max () const
Returns the least upper bound value of the distribution.
double mean () const
Returns the distribution parameter mean.
result_type min () const
Returns the greatest lower bound value of the distribution.
template<typename _UniformRandomNumberGenerator > result_type
operator() (_UniformRandomNumberGenerator &__urng)
Generating functions.
template<typename _UniformRandomNumberGenerator > result_type
operator() (_UniformRandomNumberGenerator &__urng, const param_type
&__p)
param_type param () const
Returns the parameter set of the distribution.
void param (const param_type &__param)
Sets the parameter set of the distribution.
void reset ()
Resets the distribution state.
Friends
template<typename _IntType1 , typename _CharT , typename _Traits >
std::basic_ostream< _CharT, _Traits > & operator<<
(std::basic_ostream< _CharT, _Traits > &__os, const
std::poisson_distribution< _IntType1 > &__x)
Inserts a poisson_distribution random number distribution __x into
the output stream __os.
bool operator== (const poisson_distribution &__d1, const
poisson_distribution &__d2)
Return true if two Poisson distributions have the same parameters
and the sequences that would be generated are equal.
template<typename _IntType1 , typename _CharT , typename _Traits >
std::basic_istream< _CharT, _Traits > & operator>>
(std::basic_istream< _CharT, _Traits > &__is,
std::poisson_distribution< _IntType1 > &__x)
Extracts a poisson_distribution random number distribution __x from
the input stream __is.
Detailed Description
template<typename _IntType = int>
class std::poisson_distribution< _IntType >" A discrete Poisson random
number distribution.
The formula for the Poisson probability density function is $p(i|) =
ac{^i}{i!} e^{-}$ where $$ is the parameter of the distribution.
Member Typedef Documentation
template<typename _IntType = int> typedef _IntType
std::poisson_distribution< _IntType >::result_type
The type of the range of the distribution.
Member Function Documentation
template<typename _IntType = int> result_type std::poisson_distribution<
_IntType >::max () const [inline]
Returns the least upper bound value of the distribution.
References std::numeric_limits< _Tp >::max().
template<typename _IntType = int> double std::poisson_distribution<
_IntType >::mean () const [inline]
Returns the distribution parameter mean.
template<typename _IntType = int> result_type std::poisson_distribution<
_IntType >::min () const [inline]
Returns the greatest lower bound value of the distribution.
template<typename _IntType = int> template<typename
_UniformRandomNumberGenerator > result_type std::poisson_distribution<
_IntType >::operator() (_UniformRandomNumberGenerator & __urng)
[inline]
Generating functions.
template<typename _IntType > template<typename
_UniformRandomNumberGenerator > poisson_distribution< _IntType
>::result_type std::poisson_distribution< _IntType >::operator()
(_UniformRandomNumberGenerator & __urng, const param_type & __param)
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!).
References std::abs(), std::numeric_limits< _Tp >::epsilon(),
std::log(), and std::numeric_limits< _Tp >::max().
template<typename _IntType = int> param_type std::poisson_distribution<
_IntType >::param () const [inline]
Returns the parameter set of the distribution.
template<typename _IntType = int> void std::poisson_distribution< _IntType
>::param (const param_type & __param) [inline]
Sets the parameter set of the distribution.
Parameters
__param The new parameter set of the distribution.
template<typename _IntType = int> void std::poisson_distribution< _IntType
>::reset () [inline]
Resets the distribution state.
References std::normal_distribution< _RealType >::reset().
Friends And Related Function Documentation
template<typename _IntType = int> template<typename _IntType1 , typename
_CharT , typename _Traits > std::basic_ostream<_CharT, _Traits>&
operator<< (std::basic_ostream< _CharT, _Traits > & __os, const
std::poisson_distribution< _IntType1 > & __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> bool operator== (const
poisson_distribution< _IntType > & __d1, const poisson_distribution<
_IntType > & __d2) [friend]
Return true if two Poisson distributions have the same parameters and
the sequences that would be generated are equal.
template<typename _IntType = int> template<typename _IntType1 , typename
_CharT , typename _Traits > std::basic_istream<_CharT, _Traits>&
operator>> (std::basic_istream< _CharT, _Traits > & __is,
std::poisson_distribution< _IntType1 > & __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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