An exponential_distribution random number distribution produces random numbers x > 0 distributed according to the probability density function p(x | λ) = λ e-λ x .
template<class RealType = double>
class exponential_distribution{
public:
// types
typedef RealType result_type;
typedef unspecified param_type;
// constructors and reset functions
explicit exponential_distribution(RealType lambda = 1.0);
explicit exponential_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 lambda() const;
param_type param() const;
void param(const param_type& parm);
result_type min() const;
result_type max() const;
};
Requires: 0 < lambda .
Effects: Constructs a exponential_distribution object; lambda corresponds to the parameter of the distribution.
Returns: The value of the lambda parameter with which the object was constructed.