gamma_distribution::gamma_distribution

Constructs the distribution.

gamma_distribution(result_type alpha0 = result_type(1.0));
    result_type beta0 = result_type(1.0));
explicit gamma_distribution(const param_type& par0);

alpha0

The alpha distribution parameter.

beta0

The beta distribution parameter.

par0

The parameter package used to construct the distribution.

Precondition: 0.0 < alpha0

The first constructor constructs an object whose stored value stored_alpha holds the value alpha0 and whose stored value stored_beta holds the value beta0.

The second constructor constructs an object whose stored parameters are initialized from par0.

 

// std_tr1__random__gamma_distribution_construct.cpp 
// compile with: /EHsc 
#include <random> 
#include <iostream> 
 
typedef std::ranlux64_base_01 Myeng; 
typedef std::gamma_distribution<double> Mydist; 
int main() 
    { 
    Myeng eng; 
    Mydist dist(1.5); 
    Mydist::input_type engval = eng(); 
    Mydist::result_type distval = dist(eng); 
 
    distval = distval;  // to quiet "unused" warnings 
    engval = engval; 
 
    std::cout << "alpha == " << dist.alpha() << std::endl; 
 
    dist.reset(); // discard any cached values 
    std::cout << "a random value == " << dist(eng) << std::endl; 
    std::cout << "a random value == " << dist(eng) << std::endl; 
    std::cout << "a random value == " << dist(eng) << std::endl; 
 
    return (0); 
    } 
 
alpha == 1.5
a random value == 1.69867
a random value == 0.555659
a random value == 0.609713

Header: <random>

Namespace: std

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