[daip] imagr/clean problem

Caroline E Simpson simpsonc at galaxy.fiu.edu
Wed Mar 5 13:29:36 EST 2003


Hello,

We've been having trouble with the clean in imagr in dec01. We have a 
127 channel line data set, and on some (approx 8?) channels, clean 
issues a warning (abandon clean), but then continues on the same 
channel until it hits the iteration limit -- and the result is 
essentially a large checkerboard pattern for that channel. 

We are running this on a linux system with redhat 7.2 (I believe). 

When we run the clean using a unix system running dec99, we get the 
abandon clean messages, but the clean does seem to end, and the channel 
looks normal. 

Is there some data problem with these few channels that is causing this 
behavior? Or is it truly a bug in dec01? 

I'm including the header and input files. I can also send an image of  
the checkerboard channel if you like.

Thanks,

Caroline


=================================
Dr. Caroline Simpson
Assoc. Professor
Dept. of Physics
University Park
Florida International University
Miami, FL 33199
(305) 348-1565
(305 348-6700 FAX


AIPS 1: Image=ARP135    (UV)         Filename=135D_2      .UVLIN .   1
AIPS 1: Telescope=VLA                Receiver=VLA
AIPS 1: Observer=AG564               User #=  135
AIPS 1: Observ. date=18-MAY-1999     Map date=04-MAR-2003
AIPS 1: # visibilities     23414     Sort order  TB
AIPS 1: Rand axes: UU-L-SIN  VV-L-SIN  WW-L-SIN  BASELINE  TIME1
AIPS 1:            WEIGHT  SCALE
AIPS 1: ----------------------------------------------------------------
AIPS 1: Type    Pixels   Coord value     at Pixel     Coord incr   Rotat
AIPS 1: COMPLEX      1   1.0000000E+00       1.00  1.0000000E+00    0.00
AIPS 1: STOKES       1  -1.0000000E+00       1.00 -1.0000000E+00    0.00
AIPS 1: FREQ       127   1.4174186E+09      64.00  4.8828125E+04    0.00
AIPS 1: IF           1   1.0000000E+00       1.00  1.0000000E+00    0.00
AIPS 1: RA           1    02 40 24.100       1.00       3600.000    0.00
AIPS 1: DEC          1    39 03 46.000       1.00       3600.000    0.00
AIPS 1: ----------------------------------------------------------------
AIPS 1: Coordinate equinox 2000.00
AIPS 1: Rest freq   1420.406         Vel type: OPTICAL wrt YOU
AIPS 1: Alt ref. value  6.35000E+05  wrt pixel   64.00
AIPS 1: Maximum version number of extension files of type HI is   1
AIPS 1: Maximum version number of extension files of type FQ is   1
AIPS 1: Maximum version number of extension files of type AN is   1


AIPS 1: IMAGR: Wide field imaging/Clean task
AIPS 1: Adverbs     Values                 Comments
AIPS 1: ----------------------------------------------------------------
AIPS 1: INNAME     '135D_2      '          Input UV data (name)
AIPS 1: INCLASS    'UVLIN '                Input UV data (class)
AIPS 1: INSEQ         1                    Input UV data (seq. #)
AIPS 1: INDISK        0                    Input UV data disk drive #
AIPS 1: SOURCES    *all ' '                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       0                    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       0                    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        47                    Low freq. channel 0 for cont.
AIPS 1: ECHAN        47                    Highest freq channel
AIPS 1: CHANNEL       0                    Restart channel number
AIPS 1: NPOINTS       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    'CHAN47      '          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     12          12        (X,Y) size of grid in asec
AIPS 1: IMSIZE      256         256        Minimum image size
AIPS 1: NFIELD        1                    Number of fields (max. 512)
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      20000                   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          0.1                  Clean loop gain
AIPS 1: FLUX        0.0024                 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:                                    (11-15) 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.





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