function r9lgmc (x)
c august 1977 edition.  w. fullerton, c3, los alamos scientific lab.
c
c compute the log gamma correction factor for x .ge. 10.0 so that
c  alog (gamma(x)) = alog(sqrt(2*pi)) + (x-.5)*alog(x) - x + r9lgmc(x)
c
      dimension algmcs(6)
      external alog, csevl, exp, inits, r1mach, sqrt
c
c series for algm       on the interval  0.          to  1.00000d-02
c                                        with weighted error   3.40e-16
c                                         log weighted error  15.47
c                               significant figures required  14.39
c                                    decimal places required  15.86
c
      data algmcs( 1) /    .1666389480 45186e0 /
      data algmcs( 2) /   -.0000138494 817606e0 /
      data algmcs( 3) /    .0000000098 108256e0 /
      data algmcs( 4) /   -.0000000000 180912e0 /
      data algmcs( 5) /    .0000000000 000622e0 /
      data algmcs( 6) /   -.0000000000 000003e0 /
c
      data nalgm, xbig, xmax / 0, 2*0.0 /
c
      if (nalgm.ne.0) go to 10
      nalgm = inits (algmcs, 6, r1mach(3))
      xbig = 1.0/sqrt(r1mach(3))
      xmax = exp (amin1(alog(r1mach(2)/12.0), -alog(12.0*r1mach(1))) )
c
 10   if (x.lt.10.0) call seteru (23hr9lgmc  x must be ge 10, 23, 1, 2)
      if (x.ge.xmax) go to 20
c
      r9lgmc = 1.0/(12.0*x)
      if (x.lt.xbig) r9lgmc = csevl (2.0*(10./x)**2-1., algmcs, nalgm)/x
      return
c
 20   r9lgmc = 0.0
      call seteru (34hr9lgmc  x so big r9lgmc underflows, 34, 2, 0)
      return
c
      end