DOKK / manpages / debian 10 / libstdc++-8-doc / std::poisson_distribution.3cxx.en
std::poisson_distribution< _IntType >(3cxx) std::poisson_distribution< _IntType >(3cxx)

std::poisson_distribution< _IntType > - A discrete Poisson random number distribution.


struct param_type


typedef _IntType result_type


poisson_distribution (double __mean=1.0)
poisson_distribution (const param_type &__p)
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.


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.

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.

Definition at line 4330 of file random.h.

The type of the range of the distribution.

Definition at line 4333 of file random.h.

template<typename _IntType = int> result_type std::poisson_distribution< _IntType >::max () const [inline]

Returns the least upper bound value of the distribution.

Definition at line 4429 of file random.h.

References std::numeric_limits< _Tp >::max().

Returns the distribution parameter mean.

Definition at line 4400 of file random.h.

template<typename _IntType = int> result_type std::poisson_distribution< _IntType >::min () const [inline]

Returns the greatest lower bound value of the distribution.

Definition at line 4422 of file random.h.

Generating functions.

Definition at line 4437 of file random.h.

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 1281 of file bits/random.tcc.

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.

Definition at line 4407 of file random.h.

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.

Definition at line 4415 of file random.h.

template<typename _IntType = int> void std::poisson_distribution< _IntType >::reset () [inline]

Resets the distribution state.

Definition at line 4393 of file random.h.

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.

Return true if two Poisson distributions have the same parameters and the sequences that would be generated are equal.

Definition at line 4473 of file random.h.

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.

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Sat Apr 6 2019 libstdc++