[daip] [!10241]: AIPS - IMEAN fails to report histogram RMS

[Robert Gray]

Robert Gray updated #10241
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IMEAN fails to report histogram RMS 
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           Ticket ID: 10241
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/10241
           Full Name: Robert Gray
               Email: roberthansengray at gmail.com
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): -- Unassigned --
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template Group: Default
             Created: 29 April 2017 05:59 PM
             Updated: 29 April 2017 05:59 PM
                 Due: 03 May 2017 12:00 AM (3d 6h 1m)
      Resolution Due: 09 May 2017 12:00 AM (9d 6h 1m)



Hi! 

Sometimes IMEAN fails to report a histogram RMS on cubes with a message like “IMEAN4: Histogram fit for RMS fails: plot a histogram”, and I wonder if you can give me a lead as to the cause of the problem.

I wonder if IMEAN is failing due to flagged channels in my 1024x1024x1024 cube, but it has worked on flagged channels in the past.  Oddly, if I restrict BLC and TRC to a range with no flagged channels, it does report a histogram RMS, and if I then revert to a range including the flagged channels, it also works.  I’m baffled... more details further below.

Thanks for any light you can illuminate this with!

Best wishes,

Bob Gray

AIPS 4: IMEAN:  Task to print the mean, rms and extrema in an image
AIPS 4: Adverbs     Values                 Comments
AIPS 4: ---------------------------------------------------------------
AIPS 4: DOHIST        2                    True (1.0) do histogram plot.
AIPS 4:                                    = 2 => flux on x axis
AIPS 4: USERID        0                    User ID.  ignored
AIPS 4: INNAME     '160806WOW-YC'          Image name (name)
AIPS 4: INCLASS    'YCL001'                Image name (class)
AIPS 4: INSEQ         2                    Image name (seq. #)
AIPS 4: INDISK        1                    Disk drive #
AIPS 4: BLC         100         100        Bottom left corner of image
AIPS 4:             100        *rest 0       0=>entire image
AIPS 4: TRC         924         924        Top right corner of image
AIPS 4:             924        *rest 0       0=>entire image
AIPS 4: DOINVERS     -1                    > 0 => histogram outside
AIPS 4:                                    <=0 => inside BLC/TRC
AIPS 4: NBOXES      101                    No. of ranges for histogram.
AIPS 4: PIXRANGE      0           0        Min and max range for hist.
AIPS 4: FUNCTYPE   'LG'                    'LG' => do log10 plot of #
AIPS 4:                                    samples, else linear
AIPS 4: DOMODEL       1                    > 0 fit, plot Gaussian
AIPS 4: DOCAT         2                    Put true RMS in header
AIPS 4:                                    >= 2 even for amall subimg.
AIPS 4: LTYPE         3                    Type of labeling: 1 border,
AIPS 4:                                    2 no ticks, 3 - 6 standard,
AIPS 4:                                    7 - 10 only tick labels
AIPS 4:                                    <0 -> no date/time
AIPS 4: DOPRINT       0                    0 - no print, -3 brief
AIPS 4: OUTTEXT    *all ' '                Name of output log file,
AIPS 4:                                    No output to file if blank
AIPS 4: DOTV         -1                    > 0 Do plot on the TV, else
AIPS 4:                                    make a plot file
AIPS 4: GRCHAN        0                    Graphics channel 0 => 1.
>...

>go
AIPS 4: Waiting for returned adverbs
IMEAN4: Task IMEAN  (release of 31DEC16) begins
IMEAN4: Initial guess for PIXSTD taken from robust fit
IMEAN4: ROBGET: guess of true mean and rms from sub-image only
IMEAN4: Guess is Mean= 0.0000E+00  Rms= 0.0000E+00
IMEAN4: Histogram fit for RMS fails: plot a histogram
IMEAN4: GFINIS: number records used       7
IMEAN4: Successful plot file (histogram) version      1
IMEAN4: Image= 160806WOW-YC.YCL001.   2 1   xywind=  100  100  924  924
IMEAN4: Mean and rms found by including all data:
IMEAN4: Mean= 3.826E-04 Rms= 8.774E-02 JY/BEAM  over   480521250. pixels
IMEAN4: Ignored       680625. pure-zero pixels
IMEAN4: Flux density =  9.6399E+02 Jy      beam area = 190.74 pixels
IMEAN4: Minimum=-7.9128E-01 at  551  599  620    1
IMEAN4: Skypos: RA 19 26 04.202  DEC -26 31 11.38
IMEAN4: Skypos: 1420.370 MHz  IPOL
IMEAN4: Maximum= 9.2373E-01 at  205  599  772    1
IMEAN4: Skypos: RA 19 33 48.252  DEC -26 30 34.49
IMEAN4: Skypos: 1422.315 MHz  IPOL
IMEAN4: returns adverbs to AIPS
IMEAN4: Appears to have ended successfully
IMEAN4: localhos 31DEC16 TST: Cpu=      6.6  Real=      6  IO=      2662
AIPS 4: Resumes


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