< cpp‎ | numeric‎ | random
Pseudo-random number generation
Uniform random bit generators
Engines and engine adaptors
Non-deterministic generator
Uniform distributions
Bernoulli distributions
Poisson distributions
Normal distributions
Sampling distributions
Seed Sequences
C library
Defined in header <random>
template< class RealType = double >
class gamma_distribution;
(since C++11)

Produces random positive floating-point values x, distributed according to probability density function:

P(x|α,β) =
· Γ(α)
· xα-1

where α is known as the shape parameter and β is known as the scale parameter. The shape parameter is sometimes denoted by the letter k and the scale parameter is sometimes denoted by the letter θ.

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

std::gamma_distribution satisfies RandomNumberDistribution

Template parameters

RealType - The result type generated by the generator. The effect is undefined if this is not one of float, double, or long double.

Member types

Member type Definition
result_type RealType
param_type the type of the parameter set, see RandomNumberDistribution.

Member functions

constructs new distribution
(public member function)
resets the internal state of the distribution
(public member function)
generates the next random number in the distribution
(public member function)
returns the distribution parameters
(public member function)
gets or sets the distribution parameter object
(public member function)
returns the minimum potentially generated value
(public member function)
returns the maximum potentially generated value
(public member function)

Non-member functions

compares two distribution objects
performs stream input and output on pseudo-random number distribution
(function template)


External links

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