std::gamma_distribution (3) - Linux Manuals

std::gamma_distribution: std::gamma_distribution


std::gamma_distribution - std::gamma_distribution


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

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

      \(\mathsf{p}(x\mid\alpha,\beta) = \frac{e^{-x/\beta} }{\beta^\alpha\cdot\Gamma(\alpha)}\cdot x^{\alpha-1} \)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
constructor (public member function)
              resets the internal state of the distribution
reset (public member function)


              generates the next random number in the distribution
operator() (public member function)


              returns the distribution parameters
alpha (public member function)
              gets or sets the distribution parameter object
param (public member function)
              returns the minimum potentially generated value
min (public member function)
              returns the maximum potentially generated value
max (public member function)

Non-member functions

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


 This section is incomplete
 Reason: no example

External links

Weisstein,_Eric_W._"Gamma_Distribution." From MathWorld--A Wolfram Web Resource.