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/* $OpenBSD: tgamma.c,v 1.2 2008/09/07 20:36:10 martynas Exp $ */
/* Written by Martynas Venckus, 2008, Public domain. */
#include <err.h>
#include <errno.h>
#include <math.h>
extern int errno;
#if defined(__vax__)
#define _IEEE 0
#else
#define _IEEE 1
#endif
double
infnan(int iarg)
{
switch (iarg) {
case ERANGE:
errno = ERANGE;
return (HUGE);
case -ERANGE:
errno = EDOM;
return (-HUGE);
default:
errno = EDOM;
return (0);
}
}
int
_isinf(double x)
{
if (_IEEE) {
return isinf(x);
}
else {
return errno == ERANGE;
}
}
int
_isnan(double x)
{
if (_IEEE) {
return isnan(x);
}
else {
return errno == ERANGE;
}
}
int
main(void)
{
double x;
/* Random values, approx. -177.79..171.63 */
x = tgamma(11.0); /* (11 - 1)! */
if (floor(x) != 3628800.0)
errx(1, "tgamma(11.0) = %f", x);
x = tgamma(3.5); /* 15/8 * sqrt(pi) */
if (floor(x * 100) != 332.0)
errx(1, "tgamma(3.5) = %f", x);
x = tgamma(-0.5); /* -2 * sqrt(pi) */
if (floor(x * 100) != -355.0)
errx(1, "tgamma(-0.5) = %f", x);
/* Special cases */
x = tgamma(-1); /* Negative integers */
if (!_isnan(x))
errx(1, "tgamma(-1) = %f", x);
x = tgamma(-177.8); /* x ~< -177.79 */
if (x != 0)
errx(1, "tgamma(-177.8) = %f", x);
x = tgamma(171.64); /* x ~> 171.63 */
if (!_isinf(x))
errx(1, "tgamma(171.64) = %f", x);
x = tgamma(0.0);
if (!_isinf(x) || x < 0)
errx(1, "tgamma(0) = %f", x);
x = tgamma(-0.0);
if (!_isinf(x) || x > 0)
errx(1, "tgamma(0) = %f", x);
x = tgamma(-HUGE_VAL);
if (!_isnan(x))
errx(1, "tgamma(-HUGE_VAL) = %f", x);
x = tgamma(HUGE_VAL);
if (!_isinf(x))
errx(1, "tgamma(HUGE_VAL) = %f", x);
#ifdef NAN
x = tgamma(NAN);
if (!_isnan(x))
errx(1, "tgamma(NaN) = %f", x);
#endif
return 0;
}
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