[daip] [!4920]: aips - XGAUS

[Eric Greisen]

Eric Greisen updated #4920
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       Staff (Owner): Eric Greisen (was: -- Unassigned --)
              Status: Closed (was: Open)
                 Due: - Cleared - (was: 15 May 2014 11:06 PM)

XGAUS
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           Ticket ID: 4920
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/4920
           Full Name: Lynn D Matthews
               Email: lmatthew at haystack.mit.edu
             Creator: User
          Department: AIPS Data Processing
       Staff (Owner): Eric Greisen
                Type: Issue
              Status: Closed
            Priority: Default
      Template Group: Default
             Created: 13 May 2014 11:06 PM
             Updated: 14 May 2014 03:09 PM



This is a newly overhauled task, so I guess I should expect issues.

1. FIT routine returns error code -1 - means that the number of 
    iterations has been exceeded.  You can set NITER higher
    although you may be trying to fit things that are too noisy.
    I will improve the error message in this case,

2. PIXVAL says to display on the TV for interaction only those 
    spectra that are above FLUX but less than PIXVAL.  The
    (old) assumption was that spectra above PIXVAL were reliable
    enough to not require human intervention.  The (bad) default
    is 100 * FLUX.  I will make the default 10^10 or so.

     The error message says that the full width of the Gaussian
      fit is 0.5875 channels.  and that both of the components have
      the same, improbable solution.

I am working on a memo about these 3 (soon 4) fitting tasks which
may help understand things.  Let me recommend fitting first with a
fairly high value of FLUX and then re-visiting the XG table with lower
values of FLUX until you start getting bad solutions.

I will send you a draft of the memo outside this helpdesk setup.

Cheers

Eric




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