[daip] Cryptic error in POSSM with shift

[Shami Chatterjee]

Hi: 
I'm running POSSM with this subset of inputs:

AIPS 1: SOURCES    'J1932+1059      '      Source list
AIPS 1: APARM         0           0        Control information:
AIPS 1:               0           0        1: = 0 => scalar average
AIPS 1:               0           0           > 0 => vector average
AIPS 1:               0           0        2: = 0 => self-scale
AIPS 1:               1           0           > 0 => fixed scale
AIPS 1: CODETYPE   'A&P '                  'A&P ', 'AMP ', 'PHAS',
AIPS 1: SOLINT        0                    If SOLINT > 0 then it enables
AIPS 1: NPLOTS        9                    Number of plots per page
AIPS 1: BPARM      *all 0                  More control information:

Now:
AIPS 1: ANTENNAS   *all 0                  Antennas to select
AIPS 1: BASELINE 4 *rest 0 Baselines with ANTENNAS

works, and brings up 9 plots with baselines to KP, as expected.

However, specifying a shift:
AIPS 1: SHIFT        -0.11        0.08     Position shift:

makes it crash midway, with this cryptic error:
ella  > POSSM1: Doing: KP - MK
ella  > POSSM1: -------------------------
ella  > POSSM1: Averaged  1540 visibilities from total data set of   91566
ella  > POSSM1: POSSUV: on baseline(s) KP       - NL
ella  > POSSM1: ZABORS: signal 8 received
ella  > POSSM1: ABORT!

On the other hand, I can specify
AIPS 1: ANTENNAS      6           7        Antennas to select

and bring up the plots in groups of 3 or 4, without problem.

So: no problem without shift; no problem with shift and a subset of
antennas, but a signal 8 abort if I specify a shift but no antenna
subset. 

I can work around this, but it probably points to a bug somewhere...
Replicated this with two separate data sets (though on the same targets)
but I'm not sure how to document this further.

My apologies for the flurry of complaints recently... I'm exercising AIPS
after a long gap. 
-Shami
-----------------------------------------------------------
 Shami Chatterjee       http://www.aoc.nrao.edu/~schatter/
 518 Space Sciences     
 Cornell University     Phone: (607) 255 9020
 Ithaca NY 14853        Fax  : (607) 255 8803
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