9.111 GAMMA — Gamma function

Description:

GAMMA(X) computes Gamma (\Gamma) of X. For positive, integer values of X the Gamma function simplifies to the factorial function \Gamma(x)=(x-1)!.

Standard:

Fortran 2008 and later

Class:

Elemental function

Syntax:

X = GAMMA(X)

Arguments:

X	Shall be of type REAL and neither zero nor a negative integer.

Return value:

The return value is of type REAL of the same kind as X.

Example:

          program test_gamma
            real :: x = 1.0
            x = gamma(x) ! returns 1.0
          end program test_gamma

Specific names:

Name	Argument	Return type	Standard
GAMMA(X)	REAL(4) X	REAL(4)	GNU Extension
DGAMMA(X)	REAL(8) X	REAL(8)	GNU Extension

See also:

Logarithm of the Gamma function: LOG_GAMMA