Lahey/GNU Fortran

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8.95 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