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std::gamma_distribution< _RealType > Class Template Reference
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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 2340 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 2347 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) 
) [inline, explicit]

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

Definition at line 2392 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 2413 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 2420 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 2449 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 2442 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 2457 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 2021 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 2427 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 2435 of file random.h.

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

Resets the distribution state.

Definition at line 2406 of file random.h.

Referenced by std::chi_squared_distribution< _RealType >::reset(), std::fisher_f_distribution< _RealType >::reset(), std::student_t_distribution< _RealType >::reset(), and std::negative_binomial_distribution< _IntType >::reset().

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>
template<typename _RealType1 >
bool operator== ( const std::gamma_distribution< _RealType1 > &  __d1,
const std::gamma_distribution< _RealType1 > &  __d2 
) [friend]

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

Definition at line 2472 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: