STD::POISSON_DISTRIBUTION(3cxx)

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okay so this is the manual page vibe for std::poisson_d...ion< _IntType >(3cxx) — title and 3cxx manual-name combo folded in right here so we don't need a duplicate header line. It's a discrete Poisson random number distribution and the docs are giving template realness. 💅

🌸 NAME 🌸

std::poisson_distribution< _IntType > — a discrete Poisson random number distribution. That's the whole name, no notes, periodt. ✨

✨ SYNOPSIS ✨

#include <random>

📦 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.

  • Since: C++11

🎀 Member Typedef Documentation 🎀

result_type

template<typename _IntType  = int> typedef _IntType
    std::poisson_distribution< _IntType >::result_type

The type of the range of the distribution.

🌟 Member Function Documentation 🌟

max

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().

mean

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

Returns the distribution parameter mean.

min

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

Returns the greatest lower bound value of the distribution.

operator() (_UniformRandomNumberGenerator & __urng)

template<typename _IntType  = int> template<typename
    _UniformRandomNumberGenerator > result_type std::poisson_distribution<
    _IntType >::operator() (_UniformRandomNumberGenerator & __urng) [inline]

Generating functions.

  • References: std::poisson_distribution< _IntType >::operator()().
  • Referenced by: std::poisson_distribution< _IntType >::operator()().

operator() (_UniformRandomNumberGenerator & __urng, const param_type & __param)

template<typename _IntType > template<typename _UniformRandomNumberGenerator
    > poisson_distribution< _IntType >::result_type
    std::poisson_distribution< _IntType >::operator()
    (_UniformRandomNumberGenerator & __urng, const param_type & __param)

This overload uses 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_FUNCS 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().

param

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

Returns the parameter set of the distribution.

param (const param_type & __param)

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.

reset

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

Resets the distribution state.

  • References: std::normal_distribution< _RealType >::reset().

operator<<

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.

operator==

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.

operator>>

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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