GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
CentOS 5.5 |
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gamma(3) |
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gamma, gammaf, gammal − (logarithm of the) gamma function
#include <math.h>
double
gamma(double x);
float gammaf(float x);
long double gammal(long double x);
Link with −lm.
For the definition of the Gamma function, see tgamma(3).
*BSD
version
4.4BSD and FreeBSD libm have a gamma() function that
computes the Gamma function, as one would expect.
glibc
version
Glibc has a gamma() function that is equivalent to
lgamma() and computes the natural logarithm of the
Gamma function. (This is for compatibility reasons only.
Don’t use this function.)
4.2BSD had a gamma() that computed ln(|Gamma(|x|)|), leaving the sign of Gamma(|x|) in the external integer signgam. In 4.3BSD the name was changed to lgamma(), and the man page promises
"At some time in the future the name gamma will be rehabilitated and used for the Gamma function"
This did indeed happen in 4.4BSD, where gamma() computes the Gamma function (with no effect on signgam). However, this came too late, and we now have tgamma(), the "true gamma" function.
4.2BSD. Compatible with previous mistakes.
lgamma(3), signgam(3), tgamma(3)
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gamma(3) | |