[daip] [!6572]: AIPS - IMAGR failures

[Lynn Matthews]

Lynn Matthews updated #6572
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IMAGR failures
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           Ticket ID: 6572
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/6572



I'm attempting to do bandwidth synthesis imaging of wideband continuum data and 
finding IMAGR to be fussy. I have limited experience in this area, so I don't know to what
extent this is expected, or a function of my having things poorly optimized.

Today's problem (which I've encountered before) is that after
a few CLEAN cycles, IMAGR abruptly aborts, e.g., 

IMAGR1 18:18:57 PBFCCT correcting CC for primary beam   Field    1 ch  511-  511
IMAGR1 18:18:57 PBFCCT correcting CC for primary beam   Field    1 ch  512-  512
IMAGR1 18:18:57 ZABORS: signal 11 received
IMAGR1 18:18:57 ABORT!

I'm guessing it's running out of memory? In today's case, I had 32 IFs X 16 spectral channels X 2 Stokes
and was trying to make a 1024 image.  However, a small change in GAIN from 0.1 to 0.15
allowed it to run to completion. (Is the reason for this obvious?)

If I instead average down to 8 spectral channels but keep GAIN=0.1, it still dies at a similar point, but 
now with a much more explicit explanation:

alcor.> IMAGR1: VISDFT: Begin DFT component subtraction
alcor.> IMAGR1: VISDFT: fields 1 - 1 chns 1 - 256 in 256 CC models
alcor.> IMAGR1: I Polarization model processed
alcor.> IMAGR1: VISDFT at visibility number           1
alcor.> IMAGR1: Field    1 min =  -17.0 MicroJy,max =   18.8 MicroJy
alcor.> IMAGR1: BGC Clean: using  103 cell beam + residuals >     9.05 MicroJy
alcor.> IMAGR1:    19995 Residual map points loaded
alcor.> IMAGR1: Reached minimum algorithm flux =  -14.933 MicroJy iter=       89
alcor.> IMAGR1: Total Cleaned flux density     =  396.861 MicroJy       89 comps
.
.
alcor.> IMAGR1: PBFCCT correcting CC for primary beam   Field    1 ch  255-  255
alcor.> IMAGR1: PBFCCT correcting CC for primary beam   Field    1 ch  256-  256
alcor.> IMAGR1: QINIT: did a FREE of      5310 Kwords, OFF   17477719167507
alcor.> IMAGR1: QINIT: did a GET  of    393728 Kwords, OFF   17477321427475
alcor.> IMAGR1: GRDSUB: FAILED TO GET THE NEEDED AP MEMORY
alcor.> IMAGR1: GRDSUB NEEDS  1061075 KWORDS FOR  256 MODELS, GOT   393728
alcor.> IMAGR1: OUMSUB: ERROR SUBTRACTING CLEAN field number 0001
alcor.> IMAGR1: OUMSUB: FROM UVdata work object
alcor.> IMAGR1: PBFSUB: ERROR SUBTRACTING CLEAN field number 0001
alcor.> IMAGR1: PBFSUB: FROM UVdata work object
alcor.> IMAGR1: UVSUBM: ERROR SUBTRACTING CLEAN field number 0001
alcor.> IMAGR1: UVSUBM: FROM UVdata work object
alcor.> IMAGR1: CLNUV1 : ERROR CLEANING CLEAN process object
alcor.> IMAGR1: CLNUV : ERROR CLEANING CLEAN process object
alcor.> IMAGR1: Deleting UV work file:
alcor.> IMAGR1: Destroyed  1 extension files of type AN
alcor.> IMAGR1: Destroyed  1 extension files of type FQ
alcor.> IMAGR1: Destroyed UV image file: catno=     10 disk= 3
alcor.> IMAGR1: Purports to die of UNNATURAL causes

Lynn

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