libstdc++
std::gamma_distribution< _RealType > Class Template Reference
Inheritance diagram for std::gamma_distribution< _RealType >:

List of all members.

Classes

struct  param_type

Public Types

typedef _RealType result_type

Public Member Functions

 gamma_distribution (_RealType __alpha_val=_RealType(1), _RealType __beta_val=_RealType(1))
 gamma_distribution (const param_type &__p)
_RealType alpha () const
_RealType beta () const
result_type max () const
result_type min () const
template<typename _UniformRandomNumberGenerator >
result_type operator() (_UniformRandomNumberGenerator &__urng)
template<typename _UniformRandomNumberGenerator >
result_type operator() (_UniformRandomNumberGenerator &__urng, const param_type &__p)
param_type param () const
void param (const param_type &__param)
void reset ()

Friends

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)
bool operator== (const gamma_distribution &__d1, const gamma_distribution &__d2)
template<typename _RealType1 , typename _CharT , typename _Traits >
std::basic_istream< _CharT,
_Traits > & 
operator>> (std::basic_istream< _CharT, _Traits > &__is, std::gamma_distribution< _RealType1 > &__x)

Detailed Description

template<typename _RealType = double>
class std::gamma_distribution< _RealType >

A gamma continuous distribution for random numbers.

The formula for the gamma probability density function is:

\[ p(x|\alpha,\beta) = \frac{1}{\beta\Gamma(\alpha)} (x/\beta)^{\alpha - 1} e^{-x/\beta} \]

Definition at line 2339 of file random.h.


Member Typedef Documentation

template<typename _RealType = double>
typedef _RealType std::gamma_distribution< _RealType >::result_type

The type of the range of the distribution.

Definition at line 2346 of file random.h.


Constructor & Destructor Documentation

template<typename _RealType = double>
std::gamma_distribution< _RealType >::gamma_distribution ( _RealType  __alpha_val = _RealType(1),
_RealType  __beta_val = _RealType(1) 
)
inlineexplicit

Constructs a gamma distribution with parameters $\alpha$ and $\beta$.

Definition at line 2391 of file random.h.


Member Function Documentation

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

Returns the $\alpha$ of the distribution.

Definition at line 2412 of file random.h.

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

Returns the $\beta$ of the distribution.

Definition at line 2419 of file random.h.

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

Returns the least upper bound value of the distribution.

Definition at line 2448 of file random.h.

Referenced by std::gamma_distribution< result_type >::max().

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

Returns the greatest lower bound value of the distribution.

Definition at line 2441 of file random.h.

template<typename _RealType = double>
template<typename _UniformRandomNumberGenerator >
result_type std::gamma_distribution< _RealType >::operator() ( _UniformRandomNumberGenerator &  __urng)
inline

Generating functions.

Definition at line 2456 of file random.h.

Referenced by std::gamma_distribution< result_type >::operator()().

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

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

Definition at line 2045 of file random.tcc.

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.

Definition at line 2426 of file random.h.

Referenced by std::gamma_distribution< result_type >::operator()().

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

Sets the parameter set of the distribution.

Parameters:
__paramThe new parameter set of the distribution.

Definition at line 2434 of file random.h.

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

Friends And Related Function Documentation

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:
__osAn output stream.
__xA gamma_distribution random number distribution.
Returns:
The output stream with the state of __x inserted or in an error state.
template<typename _RealType = double>
bool operator== ( const gamma_distribution< _RealType > &  __d1,
const gamma_distribution< _RealType > &  __d2 
)
friend

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

Definition at line 2470 of file random.h.

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:
__isAn input stream.
__xA gamma_distribution random number generator engine.
Returns:
The input stream with __x extracted or in an error state.

The documentation for this class was generated from the following files: