[daip] clcor with interpol='self' can fail

[Walter Brisken]

I have two VLBA datasets, BC123Q and BC123AV which were observed with 
almost identical modes.  After running APCAL I run CLCAL with 
interpol='self' as I think this produces the most sensible amplitude 
calibration.

For the first dataset, doing this blanks all solutions except a few at the 
ends of the experiment.  using interpol='' produces correct output.  The 
second dataset works fine.

I've seen this behavior on other pairs of experiments -- the first dataset 
failing and the second (and all subsequent ones) working fine.  Maybe 
there was a date cutoff after which things started to work?  If so, this 
date cutoff had to occur between Aug 8 and Sep 29, 2002.  In any case, 
there seems to be no reason for interpol='self' to fail as it does.

I've made two databases on my computer (parallax) disk 5:

AIPS 1:  122 2179 BC123Q      .TASAV .    1 UV 24-MAY-2004 08:55:57
AIPS 1:  123 2179 BC123AV     .TASAV .    1 UV 24-MAY-2004 08:58:39

In each, SN=2 is the table to apply to CL=3.  My inputs to CLCAL are 
below.

For each dataset, I made three additional CL tables.  CL=4 is the one with
interpol='self' and CL=5 is that with interpol=''.  CL=6 was made with
interpol='seln' (the "old" 'self') and appears to work in all cases.  
Thus, I believe it is a problem with the "new" version of interpol='self'.

Also from the documentation, it is unclear what happens with 
interpol='self' and dobtween=1 -- these two parameters seem contradictory!

-Walter


AIPS 1: CLCAL     Task to manage SN and CL calibration tables
AIPS 1: Adverbs     Values                 Comments
AIPS 1: ----------------------------------------------------------------
AIPS 1: INNAME     'BC123AV     '          Input UV file name (name)
AIPS 1: INCLASS    'TASAV '                Input UV file name (class)
AIPS 1: INSEQ         1                    Input UV file name (seq. #)
AIPS 1: INDISK        5                    Input UV file disk unit #
AIPS 1: SOURCES    *all ' '                Source list to calibrate
AIPS 1: SOUCODE    '    '                  Source "Cal codes"
AIPS 1: CALSOUR    *all ' '                Cal sources for calibration
AIPS 1: QUAL         -1                    Source qualifier -1=>all
AIPS 1: CALCODE    '    '                  Calibrator code '    '=>all
AIPS 1: TIMERANG   *all 0                  Time range to calibrate
AIPS 1: SUBARRAY      0                    Subarray, 0=>all,
AIPS 1: ANTENNAS   *all 0                  Antennas selected, 0=> all
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: OPCODE     '    '                  Operation 'MERG','CALI',
AIPS 1:                                    'CALP'; ' ' => 'CALI'
AIPS 1: INTERPOL   'SELF'                  Interpolation function,
AIPS 1:                                    choices are: '2PT','SIMP',
AIPS 1:                                    'AMBG','CUBE','SELF','POLY',
AIPS 1:                                    'SELN'; see HELP for details
AIPS 1: CUTOFF        0                    Interpolation limit in
AIPS 1:                                    time (min); 0=> no limit.
AIPS 1: SAMPTYPE   '    '                  Smoothing function
AIPS 1: BPARM      *all 0                  Smoothing parameters
AIPS 1: ICUT          0.1                  Cutoff for functional forms
AIPS 1: DOBLANK       0                    Blanked value interpolation
AIPS 1: DOBTWEEN      1                    > 0 -> smooth all sources
AIPS 1:                                    together; else separate them
AIPS 1: SMOTYPE    '    '                  Data to smooth
AIPS 1: SNVER         2                    Input SN table, 0=>all.
AIPS 1: INVERS        0                    Upper SN table vers in a
AIPS 1:                                    range.  0=>SNVER
AIPS 1: GAINVER       3                    Input Cal table 0=>high
AIPS 1: GAINUSE       0                    Output CAL table 0=>high+1
AIPS 1: REFANT        4                    Reference antenna 0=>pick.
AIPS 1: BADDISK       5        *rest 0     Disks to avoid for scratch