Rechercher une page de manuel
tgamma
Langue: en
Version: 2004-11-15 (fedora - 16/08/07)
Section: 3 (Bibliothèques de fonctions)
NAME
tgamma, tgammaf, tgammal - true gamma functionSYNOPSIS
#include <math.h>double tgamma(double x);
float tgammaf(float x);
long double tgammal(long double x);
Compile with -std=c99; link with -lm.
DESCRIPTION
The Gamma function is defined by
Gamma(x) = integral from 0 to infinity of t^(x-1) e^-t dt
It is defined for every real number except for non-positive integers. For nonnegative integral m one has
Gamma(m+1) = m!
and, more generally, for all x:
Gamma(x+1) = x * Gamma(x)
Furthermore, the following is valid for all values of x outside the poles:
Gamma(x) * Gamma(1-x) = PI/sin(PI*x)
This function returns the value of the Gamma function for the argument x. It had to be called "true gamma function" since there is already a function gamma() that returns something else.
ERRORS
In order to check for errors, set errno to zero and call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if errno is non-zero or fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred.A range error occurs if x is too large. A pole error occurs if x is zero. A domain error (or a pole error) occurs if x is a negative integer.
CONFORMING TO
C99.SEE ALSO
gamma(3), lgamma(3)Contenus ©2006-2024 Benjamin Poulain
Design ©2006-2024 Maxime Vantorre