%N cofreq %F $MIR/src/subs/co.for
%D Convert spectral coordinates to frequency.
%P rjs
%: coordinates
%B
      subroutine coFreq(lu,in,x1,freq)

      integer   lu
      character in*(*)
      double precision x1(*), freq
  ---------------------------------------------------------------------
  Get the frequency corresponding to a particular coordinate.

  Input:
    lu         Handle of the coordinate object.
    in         As with coCvt
    x1         As with coCvt
  Output:
    freq       The frequency.
