[daip] clean component filtering

[Amy Mioduszewski]

Hi Andy,

A way to do this without modifying CCEDT is using TABED (OPTYPE='dele').  You 
need to know the number of rows but you could find that automatically using 
GETTHEAD.  I experimented with a CC table of my own and it worked, although it 
"flags" the rows instead of getting rid of them completely.

As for IMAGRPRM(8,9), the idea is to get rid of isolated components so it sums 
up the CC within  a radius of IMAGRPRM(9) around a clean component and if that 
is less than IMAGRPRM(8) then it gets rid of that CC rather than all the CC in 
the radius.  Now that I have re-read the help file a bunch of times I think it 
is correct.  I think the ABS is correct (in a sloppy way) because if IMAGRPRM(8) 
is +ve or -ve IMAGRPRM(8) is treated as +ve.

I think if you could get IMAGRPRM(8,9) to work it would be the best way to do 
this automatically since should get rid of non-sources and you wouldn't have to 
know before hand which facets didn't contained a source(s).

Amy

Andy Biggs wrote:
> Hi Amy. Yes, the IMAGPRPRM(8,9) thing was some other problem; I tried to 
> run a 'normal' IMAGR after I emailed you and it similarly hung.
> 
> My inputs for CCEDT are:
> 
> AIPS 2: CCEDT:    Select CC components in BOXes and above minimum flux.
> AIPS 2: Adverbs     Values                 Comments
> AIPS 2: ----------------------------------------------------------------
> AIPS 2: USERID     2002                    User number.
> AIPS 2: INNAME     'TEST'                  Input file (name).
> AIPS 2: INCLASS    'ICL001'                Input file (class).
> AIPS 2: INSEQ         1                    Input file (seq. #).
> AIPS 2:                                       0 => high
> AIPS 2: INDISK        1                    Disk unit #.       0 => any
> AIPS 2: INVERS        1                    Input  file version no.
> AIPS 2: OUTVERS       0                    Output file version.
> AIPS 2: BCOUNT        1                    Beginning row to copy
> AIPS 2: ECOUNT        0                    Last row to copy: 0 => end
> AIPS 2: CUTOFF       0.05                  Minimum merged flux.  Use
> AIPS 2:                                    large negative for no edits.
> AIPS 2:                                    0.0 cuts off at zero.
> AIPS 2: BOXFILE    ' '
> AIPS 2:                                    Text file with Clean boxes
> AIPS 2: NBOXES        1                    Number of boxes in CLBOX
> AIPS 2: CLBOX         1           1        Clean windows to apply
> AIPS 2:            1024        1024        *rest 0
> AIPS 2: NCCBOX        0                    Number of boxes
> AIPS 2:                                    < 0 -> write multiple CCs
> AIPS 2: CCBOX      *all 0                  Four coordinate values for
> AIPS 2:                                    each box in arcsec.
> AIPS 2: CPARM         0.7         1.4      (1,2) = half size of rectang.
> AIPS 2:            *rest 0                   in X,Y(arcsec) in which
> AIPS 2:                                      to get total flux for
> AIPS 2:                                      CUTOFF.
> AIPS 2:                                    (1) < 0 => (2) is radius of
> AIPS 2:                                      circular aperture in CUTOFF
> AIPS 2:                                    Automatic model splitting:
> AIPS 2:                                      3 = Max number of output
> AIPS 2:                                      tables. >0 => automatic
> AIPS 2:                                      model splitting enabled.
> AIPS 2:                                      4 = Min fractional flux in
> AIPS 2:                                      the output models. 0=>0.95.
> 
> 
> In tests, I run this with gradually increasing values of CUTOFF, 
> resulting in decreasing numbers of CC components in the output file. 
> That's all perfectly fine, but at the point where all the CC components 
> are rejected it reports:
> 
> localh> CCEDT2: Task CCEDT  (release of 31DEC08) begins
> localh> CCEDT2: Merged    271 components to make    271
> localh> CCEDT2: CEDTAB: NO COMPONENTS SELECTED
> localh> CCEDT2: Purports to die of UNNATURAL causes
> localh> CCEDT2: localhost    31DEC08 TST: Cpu=       0.0  Real=       0
> 
> I would say that this is the wrong behaviour i.e. it shouldn't 'die', 
> but should at least write out a new CC table with no components in it. A 
> user presumably doesn't want the original set of clean components if 
> they've been rejected and if they don't like the empty file they can 
> just delete it. What do you think?
> 
> By the way, my attempts to experiment with the CC filtering in IMAGR 
> were somewhat thwarted, as I said, by some other unknown problem. I was 
> wondering though, do IMAGRPRM(8,9) have the same meanings as CUTOFF and 
> CPARM(1,2) in CCEDT i.e. does IMAGR sum all clean components within 
> radius IMAGRPRM(9) and reject them if this sum is less than IMAGRPRM(8)? 
> It's not terribly clear from the help which may have a typo:
> 
> (8) If non-zero, select only those Clean components having
>                 > ABS(IMAGRPRM(8)) Jy within a radius of IMAGRPRM(9)
>                 cells of the component.  If IMAGRPRM(8) < 0, the abs
>                 value of the flux near the component is used.
> 
> Is ABS(IMAGRPRM(8)) correct? The next sentence seems to say that ABS is 
> only used when this parameter is -ve.
> 
> Thanks.
> 
> Andy