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) =
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 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) | |
Generation | |
operator()
| generates the next random number in the distribution (public member function) |
Characteristics | |
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 (function) | |
performs stream input and output on pseudo-random number distribution (function template) |
Example
External links
Weisstein, Eric W. "Gamma Distribution." From MathWorld--A Wolfram Web Resource.
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