Signature Description Parameters 

template<typename T>
std::vector<T>
gen_exponential_dist(std::size_t n, const RandGenParams<T> &params = { });
Produces random non-negative floating-point values x, distributed according to probability density function:
    P(x|λ) = λe-λx
It returns the vector of results
Optional parameters to set:
lambda, seed 		T: Type can only be float, double, or long double
n: Number of numerics to generate
params: List of all applicable parameters, see DataFrameTypes.h
C++ DataFrame