complex(8) function zlog10 (z)
        implicit none
  c april 1977 version.  w. fullerton, c3, los alamos scientific lab.
        complex(8) z
        real(8) aloge
        data aloge / 0.4342944819 0325182765d0 /
  c
        zlog10 = aloge * log(z)
  c
        return
        end