GAMMA(3M) GAMMA(3M)
NAME
gamma - log gamma function
SYNOPSIS
#include <math.h>
double gamma(x)
double x;
extern int signgam;
DESCRIPTION
Gamma returns ln |Γ(x)|. The sign of Γ(x) is returned in
the external integer signgam.
EXAMPLES
Computation of the gamma function:
errno = 0;
y = gamma(x);
if(errno || (y > 88.0))
error();
y = signgam*exp(y);
DIAGNOSTICS
A large value (`HUGE') is returned for negative integer
arguments and errno is set to EDOM.
BUGS
There should be a positive indication of error.
The name should indicate the answer is a logarithm, perhaps
lgamma.