std::gamma_distribution

 

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std::gamma_distribution

Member functions

gamma_distribution::gamma_distribution

gamma_distribution::reset

Generation

gamma_distribution::operator()

Characteristics

gamma_distribution::alpha

gamma_distribution::beta

gamma_distribution::param

gamma_distribution::min

gamma_distribution::max

Non-member functions

operator== operator!=

operator<< operator>>

 

Defined in header <random>
template< class RealType = double > class gamma_distribution;		(since C++11)

Produces random positive integer values x, distributed according to probability density function:

P(x|α,β) =

e-x/β

βα · Γ(α)

· xα-1

where α is known as the shape parameter and β is known as the scale parameter.

For integer α, the value obtained is the sum of α independent exponentially distributed random variables, each of which has a mean of β

Member types

Member type	Definition
result_type	RealType
param_type	the type of the parameter set, unspecified

Member functions

(constructor)	constructs new distribution (public member function)
reset	resets the internal state of the distribution (public member function)
Generation
operator()	generates the next random number in the distribution (public member function)
Characteristics
alpha	returns the α distribution parameter (shape) (public member function)
beta	returns the β distribution parameter (scale) (public member function)
param	gets or sets the distribution parameter object (public member function)
min	returns the minimum potentially generated value (public member function)
max	returns the maximum potentially generated value (public member function)

Non-member functions

operator== operator!=	compares two distribution objects (function)
operator<< operator>>	performs stream input and output on pseudo-random number distribution (function)

External links

Weisstein, Eric W. "Gamma Distribution." From MathWorld--A Wolfram Web Resource.