CALL GSFT(T,F,NPTS,NSPEC,AMP,PHI) -- This routine does a Fourier
 series transform on a set of points.  FCTR: GS
 
 T - Independent variable array, need not be equally spaced.
 F - Dependent variable array.
 NPTS - Number of points.
 NSPEC - Number of harmonics to compute.
 AMP - RMS amplitude array.
 PHI - Phase angle array (degrees).