complex(kind(1.d0)) function zgamma (z)

        implicit none
  c july 1977 edition.  w. fullerton, c3, los alamos scientific lab.
  c a preliminary version that is portable, but not accurate enough.

        complex(kind(1.d0)) z, zlngam

        external zlngam
  c
        zgamma = exp (zlngam(z))
  c
        return
        end