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Issue reported by email - we may need to split this up by task

On Thu 2008/07/31 17:11:45 MST, Juergen Ott wrote
in a message to: Mark Calabretta <mcalabre@atnf.csiro.au>,
      Phil Edwards <Philip.Edwards@csiro.au>
and copied to: Adrienne Stilp <adrienne@astro.washington.edu>,
      Steven Warren <warren@astro.umn.edu>

Hi Juergen,

I was just wondering what the status is of upgrading MIRIAD to work with large datasets that will be delivered by CABB. In fact, right now I am using MIRIAD to reduce/image VLA data and I find that there are many issues that have to do with handling large volumes of data. E.g., the fits task is not able to convert all data in miriad format, but stops after ~3h worth of data, flagging and plotting tasks (blflag, uvplt) do

The low-level Miriad IO routines can handle large files but unfortunately the tasks themselves are limited by 4-byte, signed Fortran INTEGER variables and that causes task-specific problems of the sort you are seeing.

This is touched on briefly in the installation notes, ​ftp://ftp.atnf.csiro.au/pub/software/miriad/INSTALL.html, where task fits is mentioned by name.

not show all data, etc., and invert sometimes fails, too, because of the large datasets. I think that those things will be fixed by making MIRIAD ready for CABB data, so has there been any progress? Are there any beta versions of MIRIAD to do so?

Mark Wieringa is the one to ask.

Regards, Mark

see also: ticket:85

When attempting to produce an image cube, I get the following output:

invert vis=0208-512.5500 map=0208-512.5500.map beam=0208-512.5500.beam options=double slop=0.5

invert: Version 1.3, 2007/04/03 00:01:00 UTC

Reading the visibility data ... ### Warning: Noise variance cannot be determined for 0208-512.5500 ### Warning: ... variable systemp is missing or non-positive ### Warning: Set the variable(s) using puthd Making cubes with 2049 planes Visibilities accepted: 920 ### Warning: Number of channels with no good data: 773 ### Fatal Error: Unrecognised primary beam type ATCABB

Maxim noticed high rms values in images from CABB data. About 1/3 of the cabb channels was flagged and the invert with options=mfs produced images with rms corresponding to only a few channels of cabb data.