double gammap(double x, double a, double b);
Returns the value of the Gamma random variable distribution function with alpha a and beta b at the value x.
Parameters:
x | Critical point. |
---|---|
a | Alpha shape parameter. |
b | Beta scale parameter. |
Returns:
P(X ≤ x | a, b)
Errors:
NUMERICS_ERROR
is raised if a ≤ 0 or b ≤ 0
Usage:
double p = gammap(.5, 1.5, 2.75)
Header:
#include "contdist.h"