[daip] help with "MAXPIXELS LOADED TO AP"

Tara Chaves tchaves at astro.queensu.ca
Wed Jan 7 12:07:38 EST 2004


Hello wonderful people of the VLA.

I'm having a problem.  My dataset (AL576) is ginormous... good for 
astronomy, bad for computing.  The HI-only (continuum-subtracted, 
source-split) UV data file has over 4 million visibilities.  There are 127 
channels.

Four times, I tried to clean the data using IMAGR.  Four times it crashed 
with errors I have never seen before.  Since you are all more experienced 
than me with AIPS, perhaps you can see what I'm doing wrong.  First, here 
are the inputs I'm using:

AIPS 1: IMAGR: Wide field imaging/Clean task
AIPS 1: Adverbs     Values                 Comments
AIPS 1: ----------------------------------------------------------------
AIPS 1: INNAME     'NGC 3556    '          Input UV data (name)
AIPS 1: INCLASS    'HIONLY'                Input UV data (class)
AIPS 1: INSEQ         1                    Input UV data (seq. #)
AIPS 1: INDISK        1                    Input UV data disk drive #
AIPS 1: SOURCES    'NGC3556         '      Source name
AIPS 1: QUAL         -1                    Calibrator qualifier -1=>all
AIPS 1: CALCODE    '    '                  Calibrator code '    '=>all
AIPS 1: TIMERANG   *all 0                  Time range to use
AIPS 1: SELBAND      -1                    Bandwidth to select (kHz)
AIPS 1: SELFREQ      -1                    Frequency to select (MHz)
AIPS 1: FREQID        1                    Freq. ID to select.
AIPS 1: SUBARRAY      0                    Sub-array, 0=>all
AIPS 1: DOCALIB      -1                    If >0 calibrate data
AIPS 1:                                    = 2 calibrate weights
AIPS 1: GAINUSE      -1                    CL (or SN) table to apply
AIPS 1: DOPOL        -1                    If >0.5 correct polarization.
AIPS 1: BLVER        -1                    BL table to apply.
AIPS 1: FLAGVER      -1                    Flag table version
AIPS 1: DOBAND       -1                    If >0.5 apply bandpass cal.
AIPS 1:                                    Method used depends on value
AIPS 1:                                    of DOBAND (see HELP file).
AIPS 1: BPVER        -1                    Bandpass table version
AIPS 1: SMOOTH     *all 0                  Smoothing function. See
AIPS 1:                                    HELP SMOOTH for details.
AIPS 1: STOKES     '    '                  Stokes parameters (see HELP)
AIPS 1: BCHAN         0                    Low freq. channel 0 for cont.
AIPS 1: ECHAN         0                    Highest freq channel
AIPS 1: CHANNEL       0                    Restart channel number
AIPS 1: NCHAV         1                    Number of chan. to average.
AIPS 1: CHINC         1                    Channel incr. between maps.
AIPS 1: BIF           0                    First IF in average.
AIPS 1: EIF           0                    Last IF in average.
AIPS 1: OUTNAME    'NGC 3556    '          Output image name (name)
AIPS 1: OUTDISK       1                    Output image disk drive #
AIPS 1: OUTSEQ        0                    Output seq. no.
AIPS 1: OUTVER        0                    CC ver. no (Continuum only)
AIPS 1:                                    *** SET OUTVER ON RESTARTS
AIPS 1: IN2NAME    '            '          UV work file name
AIPS 1: IN2CLASS   '      '                UV work file class
AIPS 1: IN2SEQ        0                    UV work file seq
AIPS 1:                                    *** SET TO KEEP WORK FILE
AIPS 1: IN2DISK       0                    UV work file disk
AIPS 1: CELLSIZE      1.2         1.2      (X,Y) size of grid in asec
AIPS 1: IMSIZE     1024        1024        Minimum image size
AIPS 1: NFIELD        1                    Number of fields (max 4096)
AIPS 1: DO3DIMAG     -1                    > 0 => use different tangent
AIPS 1:                                    points for each field
AIPS 1: FLDSIZE    *all 0                  Clean size of each field.
AIPS 1: RASHIFT    *all 0                  RA shift per field (asec)
AIPS 1: DECSHIFT   *all 0                  DEC shift per field (asec)
AIPS 1: UVTAPER       0           0        (U,V) Gaussian taper
AIPS 1:                                      units are kilo-lambda
AIPS 1: UVRANGE       0           0        Min & max baseline (klambda)
AIPS 1: GUARD         0           0        x,y guard band fractional
AIPS 1:                                    radius
AIPS 1: ROTATE        0                    Rotate image CCW from N by
AIPS 1:                                    ROTATE degrees
AIPS 1: ZEROSP     *all 0                  0-spacing fluxes and weights
AIPS 1:                                    SEE HELP!!
AIPS 1: UVWTFN     'NA'                    UV dist. weight function
AIPS 1:                                      blank => uniform
AIPS 1: UVSIZE        0           0        Array size for doing uniform
AIPS 1:                                    weights.  0 -> actual field
AIPS 1:                                    size.
AIPS 1: ROBUST        0                    Robustness power: -5 -> pure
AIPS 1:                                    uniform weights, 5 => natural
AIPS 1: UVBOX         0                    Additional rows and columns
AIPS 1:                                    used in weighting.
AIPS 1: UVBXFN        1                    Box function type when UVBOX
AIPS 1:                                    > 0.  0 -> 1 round pill box.
AIPS 1: XTYPE         5                    Conv. function type in x
AIPS 1:                                      default spheroidal
AIPS 1: YTYPE         5                    Conv. function type in y
AIPS 1:                                      default spheroidal
AIPS 1: XPARM      *all 0                  Conv. function parms for x
AIPS 1: YPARM      *all 0                  Conv. function parms for y
AIPS 1: NITER      100000                  Maximum # of Clean components
AIPS 1: BCOMP      *all 0                  Begin at BCOMP component
AIPS 1:                                    Specify for each field.
AIPS 1: ALLOKAY       0                    For restart: > 0 => beams
AIPS 1:                                    okay, > 1 => work file too
AIPS 1: NBOXES        0                    Number of boxes for Clean
AIPS 1:                                    NB: field 1 only.
AIPS 1: CLBOX      *all 0                  Four coordinates for each box
AIPS 1: BOXFILE    *all ' '                Input file of field params
AIPS 1:                                    and Clean boxes; ' ' => use
AIPS 1:                                    FLDSIZE, RASHIFT, DECSHIFT,
AIPS 1:                                    NBOXES, CLBOX only.
AIPS 1: OBOXFILE   *all ' '                Output file for final Clean
AIPS 1:                                    boxes
AIPS 1: GAIN          0.2                  Clean loop gain
AIPS 1: FLUX       1.000E-04               Minimum Clean component (Jy)
AIPS 1: MINPATCH     51                    Min. BEAM half-width in AP.
AIPS 1: BMAJ          0                    FWHM(asec) major axis Clean
AIPS 1:                                    restoring beam.
AIPS 1: BMIN          0                    FWHM(asec) minor axis Clean
AIPS 1:                                    restoring beam.
AIPS 1: BPA           0                    Clean beam position angle
AIPS 1: OVERLAP       0                    1 => restore components to
AIPS 1:                                    overlapped fields, >=2=>
AIPS 1:                                    expect overlaps in Cleaning
AIPS 1: PHAT          0                    Prussian hat height.
AIPS 1: FACTOR        0                    Speedup factor see HELP
AIPS 1: CMETHOD    '    '                  Modeling method:
AIPS 1:                                    'DFT','GRID','    '
AIPS 1: IMAGRPRM   *all 0                  Task enrichment parameters
AIPS 1:                                    (1) Antenna diameter (m)
AIPS 1:                                    (2) Source Spectral index
AIPS 1:                                    (3) Frequency scaling factor
AIPS 1:                                    (4) > 0 -> SDI Clean factor
AIPS 1:                                    (5) >0 => scale residuals
AIPS 1:                                    (6) Half-width in x of box
AIPS 1:                                    (7) Half-width in y of box
AIPS 1:                                    (8) Filter components whose
AIPS 1:                                    boxes
AIPS 1: GAIN          0.2                  Clean loop gain
AIPS 1: FLUX       1.000E-04               Minimum Clean component (Jy)
AIPS 1: MINPATCH     51                    Min. BEAM half-width in AP.
AIPS 1: BMAJ          0                    FWHM(asec) major axis Clean
AIPS 1:                                    restoring beam.
AIPS 1: BMIN          0                    FWHM(asec) minor axis Clean
AIPS 1:                                    restoring beam.
AIPS 1: BPA           0                    Clean beam position angle
AIPS 1: OVERLAP       0                    1 => restore components to
AIPS 1:                                    overlapped fields, >=2=>
AIPS 1:                                    expect overlaps in Cleaning
AIPS 1: PHAT          0                    Prussian hat height.
AIPS 1: FACTOR        0                    Speedup factor see HELP
AIPS 1: CMETHOD    '    '                  Modeling method:
AIPS 1:                                    'DFT','GRID','    '
AIPS 1: IMAGRPRM   *all 0                  Task enrichment parameters
AIPS 1:                                    (1) Antenna diameter (m)
AIPS 1:                                    (2) Source Spectral index
AIPS 1:                                    (3) Frequency scaling factor
AIPS 1:                                    (4) > 0 -> SDI Clean factor
AIPS 1:                                    (5) >0 => scale residuals
AIPS 1:                                    (6) Half-width in x of box
AIPS 1:                                    (7) Half-width in y of box
AIPS 1:                                    (8) Filter components whose
AIPS 1:                                    neighborhood is weaker than
AIPS 1:                                    IMAGRPRM(8) Jy.  0 -> don't
AIPS 1:                                    (9) Radius in pixels for the
AIPS 1:                                    IMAGRPRM(8) test.
AIPS 1:                                    (10) multiplier of image size
AIPS 1:                                    to get beam size: 0 => 2;
AIPS 1:                                    2, 1, 0.5 0.25 supported
AIPS 1:                                    (11-16) Multi-resolution
AIPS 1:                                    added controls
AIPS 1:                                    (20) Retry factor (see help)
AIPS 1:                                    (20) Retry factor (see help)
AIPS 1: NGAUSS        0                    Number of resolutions to use
AIPS 1: WGAUSS     *all 0                  Resolutions in arc sec >= 0
AIPS 1: FGAUSS     *all 0                  Minimum flux for each resol.
AIPS 1: MAXPIXEL      0                    Maximum pixels searched in
AIPS 1:                                    each major cycle.
AIPS 1: DOTV         -1                    Display residuals on TV ?
AIPS 1:                                    Start with field = DOTV
AIPS 1: BADDISK    *all 0                  Disks to avoid for scratch.


And here are the interesting error messages I've been getting...

   1    8   08-NOV-2003  04:50:51     IMAGR     WARNING: > MAXPIXELS 
LOADED TO AP!!

  1    4   08-NOV-2003  05:18:30     IMAGR     Field   1 min =   -1.1 
MilliJy,max =    1.0 MilliJy
(This is the time it crashed.  There was no error message recorded in the 
AIPS MSSVR but I did get a "Oops:002" error in my system log.  By the 
way, I was also running all cleans in failsafe mode on my laptop.)

   1    4   08-NOV-2003  15:30:13     IMAGR     Beginning channel    2 
through    2 with  1 IFs
   1    2   08-NOV-2003  15:34:51     IMAGR     OUVIMG: Sorting data to 
make them fit
   1    2   08-NOV-2003  15:41:46     IMAGR     GRIDUV: Only   315 Rows in  
1280k AP
   1    2   08-NOV-2003  15:41:46     IMAGR     GRIDUV: Max U Baseline       
52430. lambda (=  626 cells)
   1    2   08-NOV-2003  15:41:46     IMAGR     GRIDUV: Frequency 
1.415591E+09 Hz
   1    8   08-NOV-2003  15:41:46     IMAGR     GRIDUV: SORT ERROR: ROWS   
340   348 OUTSIDE  -202   112
   1    7   08-NOV-2003  15:41:46     IMAGR     OUVIMG: MAKING BEAM BEAM 
image for CLEAN
   1    8   08-NOV-2003  15:41:46     IMAGR     OUVIMG: FROM UVdata work 
object
   1    8   08-NOV-2003  15:41:46     IMAGR     CLNINI: ERROR OPENING 
CLEAN process object
   1    8   08-NOV-2003  15:41:46     IMAGR     CLNUV : ERROR CLEANING 
CLEAN process object
   1    6   08-NOV-2003  15:41:46     IMAGR     Deleting UV work file:
   1    4   08-NOV-2003  15:41:46     IMAGR     Destroyed  4 extension 
files of type AN
   1    4   08-NOV-2003  15:41:46     IMAGR     Destroyed  1 extension 
files of type FQ
   1    4   08-NOV-2003  15:41:46     IMAGR     Destroyed UV image file: 
catno=      2 disk= 3
   1    3   08-NOV-2003  15:41:46     IMAGR     Purports to die of 
UNNATURAL causes
   1    5   08-NOV-2003  15:41:46     IMAGR     avalon       31DEC02 TST: 
Cpu=     892.8  Real=    3315

   1    8   08-NOV-2003  19:27:33     IMAGR     WARNING: > MAXPIXELS 
LOADED TO AP!!

  1    8   08-NOV-2003  23:07:14     IMAGR     WARNING: > MAXPIXELS LOADED 
TO AP!!
 
   1    8   08-NOV-2003  23:26:32     IMAGR     ALGSUB: ERROR: DATA 
OUTSIDE OF UV GRID USED:
   1    8   08-NOV-2003  23:26:32     IMAGR             UMAX =  
8.54268E+04 VMAX =  8.54268E+04 WAVELENGTH
   1    8   08-NOV-2003  23:26:32     IMAGR     OUMSUB: ERROR SUBTRACTING 
CLEAN field number 0001
   1    8   08-NOV-2003  23:26:32     IMAGR     OUMSUB: FROM UVdata work 
object
   1    8   08-NOV-2003  23:26:32     IMAGR     UVSUBM: ERROR SUBTRACTING 
CLEAN field number 0001
   1    8   08-NOV-2003  23:26:32     IMAGR     UVSUBM: FROM UVdata work 
object
   1    8   08-NOV-2003  23:26:32     IMAGR     CLNUV : ERROR CLEANING 
CLEAN process object
   1    6   08-NOV-2003  23:26:32     IMAGR     Deleting UV work file:
   1    4   08-NOV-2003  23:26:32     IMAGR     Destroyed  4 extension 
files of type AN
   1    4   08-NOV-2003  23:26:32     IMAGR     Destroyed  1 extension 
files of type FQ
   1    4   08-NOV-2003  23:26:32     IMAGR     Destroyed UV image file: 
catno=      2 disk= 3
   1    3   08-NOV-2003  23:26:32     IMAGR     Purports to die of 
UNNATURAL causes
   1    5   08-NOV-2003  23:26:32     IMAGR     avalon       31DEC02 TST: 
Cpu=    6665.8  Real=   20623
  
   1    8   09-NOV-2003  17:37:16     IMAGR     WARNING: > MAXPIXELS 
LOADED TO AP!!

 1    5   09-NOV-2003  18:16:26     IMAGR     SOMETHING IS GOING WRONG - 
ABANDON CLEAN
  
  1    5   09-NOV-2003  18:17:32     IMAGR     SOMETHING IS GOING WRONG - 
ABANDON CLEAN

   1    4   09-NOV-2003  21:40:40     IMAGR     Beginning channel   16 
through   16 with  1 IFs
   1    2   09-NOV-2003  21:45:18     IMAGR     OUVIMG: Sorting data to 
make them fit
   1    2   09-NOV-2003  21:52:19     IMAGR     GRIDUV: Only   315 Rows in  
1280k AP
   1    2   09-NOV-2003  21:52:19     IMAGR     GRIDUV: Max U Baseline       
52442. lambda (=  626 cells)
      avalon     AIPS (31DEC02)     221               10-NOV-2003   
12:34:42               Page  211
Pops  Prior    Date        Time       Task          Messages for user  221
 
   1    2   09-NOV-2003  21:52:19     IMAGR     GRIDUV: Frequency 
1.415933E+09 Hz
   1    8   09-NOV-2003  21:52:26     IMAGR     GRIDUV: SORT ERROR: ROWS    
38    46 OUTSIDE  -310     4
   1    7   09-NOV-2003  21:52:26     IMAGR     OUVIMG: MAKING BEAM BEAM 
image for CLEAN
   1    8   09-NOV-2003  21:52:26     IMAGR     OUVIMG: FROM UVdata work 
object
   1    8   09-NOV-2003  21:52:26     IMAGR     CLNINI: ERROR OPENING 
CLEAN process object
   1    8   09-NOV-2003  21:52:26     IMAGR     CLNUV : ERROR CLEANING 
CLEAN process object
   1    6   09-NOV-2003  21:52:26     IMAGR     Deleting UV work file:
   1    4   09-NOV-2003  21:52:26     IMAGR     Destroyed  4 extension 
files of type AN
   1    4   09-NOV-2003  21:52:26     IMAGR     Destroyed  1 extension 
files of type FQ
   1    4   09-NOV-2003  21:52:26     IMAGR     Destroyed UV image file: 
catno=      1 disk= 3
   1    3   09-NOV-2003  21:52:26     IMAGR     Purports to die of 
UNNATURAL causes
   1    5   09-NOV-2003  21:52:26     IMAGR     avalon       31DEC02 TST: 
Cpu=   12051.8  Real=   37080


Now, a collaborator of mine suggested something about an archaic AP memory 
thing filling up with the Fourier transforms and that I try using IMAGR 
first to do the transforms and then use APCLN to do the cleaning.  I did 
that, used IMAGR to make a dirty cube, then APCLN with the same parameters 
as above to clean the cube, only these data came out with a nice ring 
around the galaxy.  Most frustrating.  For a given channel with HI 
emission, cleaning with the above parameters using IMAGR results in a nice 
image with no ring, but if I take the same channel and make a dirty imagr 
with IMAGR first, then clean with APCLN, I get the ring.  I have no idea 
why.

I next tried cleaning three successive channels with HI emission, each 
separately with IMAGR.  I then tried using MCUBE to combine these three 
2-D images into a cube.  Here are the inputs I used:

AIPS 1: MCUBE:  Task to collect a set of n-dim maps into a (n+1)-dim map
AIPS 1: Adverbs     Values                 Comments
AIPS 1: ----------------------------------------------------------------
AIPS 1: USERID        0                    User ID.  0 => current user,
AIPS 1:                                      32000 => any user.
AIPS 1: INNAME     'TEST        '          Input name(name).
AIPS 1: INCLASS    'ICL001'                Input name(class).
AIPS 1: INSEQ         1                    Input name(seq. #). 0=>high
AIPS 1:                                    First sequence # in the set
AIPS 1: INDISK        3                    Input disk drive #. 0=>any
AIPS 1: IN2SEQ        2                    Last sequence # in set.
AIPS 1: IN3SEQ        3                    Sequence # increment.
AIPS 1: OUTNAME    'TEST        '          Output name(name).
AIPS 1: OUTCLASS   'ICL001'                Output name(class).
AIPS 1: OUTSEQ        4                    Output name(seq. #).
AIPS 1:                                      0 => highest unique
AIPS 1: OUTDISK       3                    Output image disk drive #
AIPS 1:                                      0 => highest with space
AIPS 1: DOALIGN       1                    Alignment control parm
AIPS 1: AXREF         1                    n+1 axis pixel of map INSEQ.
AIPS 1:                                    0 => 1
AIPS 1: AX2REF        2                    n+1 axis pixel of map IN2SEQ
AIPS 1:                                    0 => opposite end from INSEQ
AIPS 1: NPOINTS       3                    Number of pixels on axis n+1
>go

Here are the resultant messages:

AVALON> MCUBE1: Task MCUBE  (release of 31DEC02) begins
AVALON> MCUBE1: Create TEST        .ICL001.   4 (MA)  on disk  3  cno    1
AVALON> MCUBE1: Writing sequence #    1 to plane    1
AVALON> MCUBE1: Blanking empty output plane    2
AVALON> MCUBE1: Blanking empty output plane    3
AVALON> MCUBE1: Appears to have ended successfully
AVALON> MCUBE1: avalon       31DEC02 TST: Cpu=       0.2  Real=       1

The resultant cube consists of one channel of data and then two 
completely blanked channels.  Yet the input channels do contain data.

I would be eternally grateful for any help or advice here on how to clean 
this gigantic data set.  Obviously, the UV data are much too big to ftp 
down there but I am currently residing in Albuquerque and I'd be more than 
happy to drive my laptop down to Socorro for someone to play with.  My 
schedule is open, any time is fine... besides, I still owe Greg Taylor a 
beer!

Thanks so much for your help, O wiser-than-I AIPS-gurus!

Tara Mowery
PhD Candidate, Physics
Queen's University at Kingston








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