calc_gamma_series Function

private function calc_gamma_series(a, x) result(gamma_series)

solves the normalized lower gamma function

$\gamma(a,x) / \Gamma(a) = x^{a} * \gamma*(a,x)$

see Equation 8.7.1 $\gamma(a,x) = exp(-x) * \sum_{k=0}^{\infty} \frac{x^{k}}{\Gamma(a+k+1)}$

input: a = gamma function argument, x = upper limit of integration

output: normalized lower gamma function $\gamma(a, x) / \Gamma(a)$

Arguments

Type	Intent	Optional	Attributes		Name
real(kind=wp),	intent(in)			::	a
real(kind=wp),	intent(in)			::	x

Return Value real(kind=wp)