CS
 CSR    Calculate chi-squared for logarithm of reflectivity.

 FR     Fit logarithm of reflectivity to data stored in IF.

 FRM    Fit logarithm of reflectivity to data stored in IF and plot a
        movie of the fit as it progresses.  Append A, B, C or D to watch
        only the specified cross-sections.

 UF     Restore parameters and uncertainties to values just before the last
        fit.

 RE     Determine number of points required for resolution extension
        (automatically done whenever necesssary).

 EC     Edit constraints found in the file entered using PF command.
        A new constrain module is created and loaded (automatically done
        when the program runs).

 LC     Reload the constrain module.  The module is not rebuilt, only
        reloaded.

 UC     Update constraints (automatically done whenever necessary).

 ULC    Unload the constrain module and revert to no constraints.

 VAnm   Toggle status of nmth fit parameter.  Toggles between varied and
        fixed in the fit.  Specify nm as you would for entering its value.

 VANONE Turn off all varied parameters