[daip] AIPS antenna numbers

[Colin Lonsdale]

Hi Eric,

Nearly 2 years ago now I asked your advice on a version of AIPS capable of >90 antennas (see below).  I never got round to implementing it, and last summer my REU student worked on VLBA data, not MWA data.  Now I have another student and we again want to use AIPS for MWA.  I have a version compiled with MAXANT=200 in PUVD.INC, on an Ubuntu Linux box.  Things seemed to work OK, and PRTAN, UVPLT etc showed the data present for all 128 antennas OK.  However, when attempting IMAGR (and I went back to UVMAP as well for a test), it seems something is getting overwritten, I assume in a common block somewhere.  I get lots of error messages from UVWAIT, claiming zero weight for thousands of data points.  By specifying UVWTFN = NA I can get those to go away, but the task still dies nastily, with the sum of gridding weights=0, and silly numbers coming out of QINIT.  The error messages are copied at the end of this message.

To make sure this is not something wrong with the MWA data files, I tried the MAXANT=200 version on last summer's VLBA data and got the same result - the messages below are from the VLBA data that was successfully processed a year ago.  I tried to do some grepping around for where the problem might be, and saw some hardcoded array sizes in PUVD.INC, like XBTBSZ, but I really don't know where to look - it's been a long time since I messed around in the guts of AIPS.

So, any insights or help you can offer would be very gratefully received.  We are a bit stuck here, and the tools in AIPS for exploring the behavior of MWA data are very much needed.

- Colin

On Oct 25, 2013, at 1:27 PM, Eric Greisen <egreisen at nrao.edu> wrote:

> Colin Lonsdale wrote:
>> Hi Eric,
>> In another rare circumstance, I find myself trying to analyze some MWA data.  It has 128 antennas so I have instantly discovered that I can't get to first base without getting below the apparent AIPS limit of 90 antennas.  I can afford to throw away 38 of the antennas (since they are in useless locations for the investigation I am trying to do) but I can't find a way to get a consistent dataset that refers only to antenna numbers of 90 or less - I would need to renumber both antennas and baselines.  INDXR and various other tasks simply choke on the file.
>> What I am trying to do is use trusted and well understood AIPS calibration tasks to see if the DR limitation in some MWA solar images is a CASA problem.  There is tons of SNR and superb uv coverage, but Divya Oberoi has been reducing this in CASA and can't seem to get better than 500:1.
>> Is there any way to deal with this from within AIPS, or do I have to find a way to edit the dataset before generating the uvfits file so that AIPS sees only what it likes?
>> Thanks,
>> - Colin
> 
> If you are able to compile AIPS rather than use the binary distribution, then you could change $INC/PUVD.INC parameter MAXANT before doing so and then build with a higher allowed limit.  The 90 was based on a Japanese solar interferometer with 80 some.  There will be some annoyances from formats that know that I2 is enough but it should work up to MAXANT of 200 or so.  There is a deeper limit at 255 in the encoding of baseline numbers.
> 
> I use gcc 4.1.2 and g77 3.4.6 (which are quite old) on my personal Linux machine.  Intel compilers work fine as do some gfortran versions (4.2.1 worked but 4.0 and 4.1 did not).
> 
> Eric Greisen
> 

UVWAIT error messages - continues for many thousands of lines, I assume one per data point ...

localh> IMAGR1: UVWAIT U, V, NR, WT <= 0   53 1088   2511203  0.0000E+00
localh> IMAGR1: UVWAIT U, V, NR, WT <= 0   53 1088   2511203  0.0000E+00
localh> IMAGR1: UVWAIT U, V, NR, WT <= 0   53 1089   2511204  0.0000E+00
localh> IMAGR1: UVWAIT U, V, NR, WT <= 0   53 1089   2511204  0.0000E+00
localh> IMAGR1: UVWAIT U, V, NR, WT <= 0   53 1089   2511204  0.0000E+00
localh> IMAGR1: UVWAIT U, V, NR, WT <= 0   54 1089   2513251  0.0000E+00
localh> IMAGR1: UVWAIT U, V, NR, WT <= 0   54 1089   2513251  0.0000E+00
localh> IMAGR1: UVWAIT U, V, NR, WT <= 0   54 1089   2513251  0.0000E+00
localh> IMAGR1: UVWAIT U, V, NR, WT <= 0   54 1089   2513251  0.0000E+00
localh> IMAGR1: UVWAIT U, V, NR, WT <= 0   54 1089   2513251  0.0000E+00
localh> IMAGR1: UVWAIT U, V, NR, WT <= 0   54 1089   2513251  0.0000E+00
localh> IMAGR1: UVWAIT U, V, NR, WT <= 0   54 1089   2513251  0.0000E+00
localh> IMAGR1: UVWAIT U, V, NR, WT <= 0   54 1090   2513252  0.0000E+00
localh> IMAGR1: UVWAIT U, V, NR, WT <= 0   54 1090   2513252  0.0000E+00


Error messages from IMAGR ...

localh> IMAGR1: Task IMAGR  (release of 31DEC15) begins
localh> IMAGR1: Using temporary OBOXFILE = 'HOME:OBOXtemp20150622.090806'
localh> IMAGR1: UVGET: doing no flagging this time
localh> IMAGR1: Create J1500-0649  .IMAGR .   2 (UV)  on disk  2  cno    4
localh> IMAGR1: Beginning channel    1 through    4 with  8 IFs
localh> IMAGR1: IMACPY: Copied     8224 visibilities to be imaged
localh> IMAGR1: **** WARNING data included out of inner portion of UV plane ****
localh> IMAGR1: **** Watch for high-frequency & other poor cleaning effects ****
localh> IMAGR1: Create TEST        .IBM001.   1 (MA)  on disk  2  cno   15
localh> IMAGR1: Create TEST        .ICL001.   1 (MA)  on disk  2  cno   17
localh> IMAGR1: QINIT: did a GET  of      5310 Kwords, OFF   17512442861263
localh> IMAGR1: GRDFLT: X and Y convolution type = SPHEROIDAL
localh> IMAGR1: GRDFLT: X and Y parms =  3.0000  1.0000
localh> LOGFILE FOR USER 1080 GETTING LARGE: USE PRTMSG AND CLRMSG NOW!         
localh> IMAGR1: GRDFLT: convolution function sampled every 1/100 of a cell
localh> IMAGR1: GRDMEM: Ave   32 Channels; 4.631875E+09 to 4.879875E+09 Hz
localh> IMAGR1: Field    1 Sum of gridding weights =  0.00000E+00
localh> IMAGR1: Field    1 Beam min =  100.0 Exa  Jy, max =    0.0      Jy
localh> IMAGR1: FITBM: SOLUTION FOR RESTORING BEAM FAILED
localh> IMAGR1: Fit Gaussian FWHM =  679.772 x  679.772 Microarcsec, PA=   45.0
localh> IMAGR1: BEAM HISTOGRAM PATHOLOGICAL - DEALING WITH IT
localh> IMAGR1: CLBHIS: minimum component 0.000 of current peak
localh> IMAGR1: QINIT: did a FREE of      5310 Kwords, OFF   17512442861263
localh> IMAGR1: QINIT: did a GET  of      8894 Kwords, OFF   17512439191247
localh> IMAGR1: Field    1 min =  100.0 Exa  Jy,max =    0.0      Jy
localh> IMAGR1: BGC Clean: using  103 cell beam + residuals >    43.79 Mega Jy
localh> IMAGR1:    19986 Residual map points loaded
localh> IMAGR1: CLACLN: ILLEGAL FIELD NUMBER***, NOT  1-  1
localh> IMAGR1: CLACLN: FINDING COMPONENTS
localh> IMAGR1: CLNCYC: ERROR CLEANING CLEAN process object
localh> IMAGR1: CLNUV1 : ERROR CLEANING CLEAN process object
localh> IMAGR1: CLNUV : ERROR CLEANING CLEAN process object
localh> IMAGR1: Deleting UV work file:
localh> IMAGR1: Destroyed  1 extension files of type AN