std::gamma_distribution< _RealType >(3) Library Functions Manual std::gamma_distribution< _RealType >(3)

std::gamma_distribution< _RealType > - A gamma continuous distribution for random numbers.

#include <random>


struct param_type


typedef _RealType result_type


gamma_distribution ()
Constructs a gamma distribution with parameters 1 and 1. gamma_distribution (_RealType __alpha_val, _RealType __beta_val=_RealType(1))
Constructs a gamma distribution with parameters $ lpha$ and $ gamma_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)
_RealType alpha () const
Returns the $ lpha$ of the distribution. _RealType beta () const
Returns the $ distribution. result_type max () const
Returns the least upper bound value of the distribution. 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 _RealType1, typename _CharT, typename _Traits> std::basic_ostream< _CharT, _Traits > & operator<< (std::basic_ostream< _CharT, _Traits > &__os, const std::gamma_distribution< _RealType1 > &__x)
Inserts a gamma_distribution random number distribution __x into the output stream __os. bool operator== (const gamma_distribution &__d1, const gamma_distribution &__d2)
Return true if two gamma distributions have the same parameters and the sequences that would be generated are equal. template<typename _RealType1, typename _CharT, typename _Traits> std::basic_istream< _CharT, _Traits > & operator>> (std::basic_istream< _CharT, _Traits > &__is, std::gamma_distribution< _RealType1 > &__x)
Extracts a gamma_distribution random number distribution __x from the input stream __is.

class std::gamma_distribution< _RealType >"A gamma continuous distribution for random numbers.

The formula for the gamma probability density function is: p(x|lpha,ac{1}{
(x/^{-x/ ]

Since

C++11

The type of the range of the distribution.

template<typename _RealType = double> std::gamma_distribution< _RealType >::gamma_distribution () [inline]

Constructs a gamma distribution with parameters 1 and 1.

template<typename _RealType = double> std::gamma_distribution< _RealType >::gamma_distribution (_RealType __alpha_val, _RealType __beta_val = _RealType(1)) [inline], [explicit]

Constructs a gamma distribution with parameters $lpha$ and $

template<typename _RealType = double> _RealType std::gamma_distribution< _RealType >::alpha () const [inline]

Returns the $lpha$ of the distribution.

template<typename _RealType = double> _RealType std::gamma_distribution< _RealType >::beta () const [inline]

Returns the $ distribution.

template<typename _RealType = double> result_type std::gamma_distribution< _RealType >::max () const [inline]

Returns the least upper bound value of the distribution.

template<typename _RealType = double> result_type std::gamma_distribution< _RealType >::min () const [inline]

Returns the greatest lower bound value of the distribution.

Generating functions.

Referenced by operator()().

Marsaglia, G. and Tsang, W. W. "A Simple Method for Generating Gamma Variables" ACM Transactions on Mathematical Software, 26, 3, 363-372, 2000.

References std::log(), and std::pow().

template<typename _RealType = double> param_type std::gamma_distribution< _RealType >::param () const [inline]

Returns the parameter set of the distribution.

template<typename _RealType = double> void std::gamma_distribution< _RealType >::param (const param_type & __param) [inline]

Sets the parameter set of the distribution.

Parameters

__param The new parameter set of the distribution.

template<typename _RealType = double> void std::gamma_distribution< _RealType >::reset () [inline]

Resets the distribution state.

template<typename _RealType = double> template<typename _RealType1, typename _CharT, typename _Traits> std::basic_ostream< _CharT, _Traits > & operator<< (std::basic_ostream< _CharT, _Traits > & __os, const std::gamma_distribution< _RealType1 > & __x) [friend]

Inserts a gamma_distribution random number distribution __x into the output stream __os.

Parameters

__os An output stream.
__x A gamma_distribution random number distribution.

Returns

The output stream with the state of __x inserted or in an error state.

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

template<typename _RealType = double> template<typename _RealType1, typename _CharT, typename _Traits> std::basic_istream< _CharT, _Traits > & operator>> (std::basic_istream< _CharT, _Traits > & __is, std::gamma_distribution< _RealType1 > & __x) [friend]

Extracts a gamma_distribution random number distribution __x from the input stream __is.

Parameters

__is An input stream.
__x A gamma_distribution random number generator engine.

Returns

The input stream with __x extracted or in an error state.

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