DIPSO has access to a suite of subroutines which are designed to fit a variety of line profiles to observed data. The commands really need a bit more explanation than can readily be put into the alphabetical reference list which follows; so here's a bit more explanation...
The primary purpose of the ELF routines is to separate blends by fitting multiple profiles. Gaussian profiles are the most commonly used, but other analytic forms are possible, as are `numerical' profiles. Facilities are provided for constraining line centre positions, widths, and relative fluxes, so that known atomic data (such as relative wavelengths or intensities within multiplets) can be utilised. The option of relative flux constraint is particularly useful when analysing optically thin emission lines (hence Emission Line Fitting), but the package is entirely happy with absorption lines (which it treats as emission lines with negative fluxes), or any other form of data that can be reasonably approximated with the available profile forms.
Fits are made to the spectrum data stored in the DIPSO `current'
arrays. The continuum level may be set to zero by manipulations within
DIPSO, or a polynomial fit to the continuum can be made simultaneously
with the profile fitting. (The former option is strongly
recommended.) Specification of constraints and starting values for
the fit parameters is done in a command language (invoked by the DIPSO
command ELFINP) which is described below. After optimisation of
parameters (DIPSO command ELFOPT), the full specification of the
fit and the results may be stored. The resulting fit, in spectrum
form, can be pushed on the DIPSO stack (ELFPUSH).
DIPSO --- A friendly spectrum analysis program