NAME

gamma − log gamma function

USAGE

#include <math.h>

double gamma(x)
double x;

DESCRIPTION

Gamma returns ln |Γ(|x|)|. The sign of Γ(|x|) is returned in the external integer signgam. 

EXAMPLE

The following C program might be used to calculate Γ:

y = gamma(x);
if (y > 88.0)
error();
y = exp(y);
if(signgam)
y = −y;

NOTES

There is no positive indication of error. 

DIAGNOSTICS

A huge value is returned for negative integer arguments.