gamma(x) computes Gamma () of x. For positive, integer values of x the Gamma function simplifies to the factorial function .
Fortran 2008 and later
x = gamma(x)
x - Shall be of type real and neither zero nor a negative integer.The return value is of type real of the same kind as x.
program test_gamma
real :: x = 1.0
x = gamma(x) ! returns 1.0
end program test_gamma
Logarithm of the Gamma function: log_gamma