LGAMMA(3) | Library Functions Manual | LGAMMA(3) |
lgamma
, lgammaf
,
lgamma_r
, lgammaf_r
,
gamma
, gammaf
,
gamma_r
, gammaf_r
,
tgamma
, tgammaf
—
#include <math.h>
extern int signgam;
double
lgamma
(double
x);
float
lgammaf
(float
x);
double
lgamma_r
(double
x, int *sign);
float
lgammaf_r
(float
x, int *sign);
double
gamma
(double
x);
float
gammaf
(float
x);
double
gamma_r
(double
x, int *sign);
float
gammaf_r
(float
x, int *sign);
double
tgamma
(double
x);
float
tgammaf
(float
x);
lgamma
(x) returns ln|Γ(x)|.
The external integer signgam returns the sign of Γ(x).
lgamma_r
() is a reentrant interface that
performs identically to lgamma
(), differing in that
the sign of Γ(x) is stored in the location pointed to by the
sign argument and signgam is not
modified.
The tgamma
(x) and
tgammaf
(x) functions return
Γ(x), with no effect on signgam.
gamma
(), gammaf
(),
gamma_r
(), and gammaf_r
()
are deprecated aliases for lgamma
(),
lgammaf
(), lgamma_r
(), and
lgammaf_r
(), respectively.
signgam∗exp(lgamma(x))
” to
compute g := Γ(x). Instead use a program like this (in C):
lg = lgamma(x); g = signgam∗exp(lg);
Only after lgamma
() has returned can
signgam be correct.
lgamma
() returns appropriate values unless an argument
is out of range. Overflow will occur for sufficiently large positive values,
and non-positive integers. For large non-integer negative values,
tgamma
() will underflow. On the VAX, the reserved
operator is returned, and errno is set to
ERANGE
.
lgamma
function appeared in
4.3BSD. The tgamma
() function
appeared in NetBSD 6.0.
May 4, 2012 | NetBSD 9.0 |