gammaLowerIncomplete function

double gammaLowerIncomplete(
  1. double a,
  2. double x
)

Returns the lower incomplete gamma function gamma(a,x) = int(exp(-t)t^(a-1),t=0..x) for real a > 0, x > 0.

Implementation

double gammaLowerIncomplete(double a, double x) =>
    gammaLowerRegularized(a, x) * gamma(a);