gammav

double gammav(double x, double a, double b);

Returns the critical point of the Gamma random variable distribution function with alpha a and beta b associated with probability p.

Parameters:
xCummulative probability for the critical point.
aAlpha shape parameter.
bBeta scale parameter.

Returns:
x such that P(X ≤ x | a, b) = p

Errors:
NUMERICS_ERROR is raised if a ≤ 0, b ≤ 0, p ≤ 0, or p ≥ 1

Usage:
double x = gammav(.5, 1.5, 2.75)

Header:
#include "contdist.h"