A gamma_distribution random number distribution produces random numbers x > 0 distributed according to the probability density function p(x | α,β) = e-x/β βα · Γ(α) · x α-1 .
template<class RealType = double> class gamma_distribution{ public: // types typedef RealType result_type; typedef unspecified param_type; // constructors and reset functions explicit gamma_distribution(RealType alpha = 1.0, RealType beta = 1.0); explicit gamma_distribution(const param_type& parm); void reset(); // generating functions template<class URNG> result_type operator()(URNG& g); template<class URNG> result_type operator()(URNG& g, const param_type& parm); // property functions RealType alpha() const; RealType beta() const; param_type param() const; void param(const param_type& parm); result_type min() const; result_type max() const; };
explicit gamma_distribution(RealType alpha = 1.0, RealType beta = 1.0);
Requires: 0 < alpha and 0 < beta .
Effects: Constructs a gamma_distribution object; alpha and beta correspond to the parameters of the distribution.
Returns: The value of the alpha parameter with which the object was constructed.
Returns: The value of the beta parameter with which the object was constructed.