[daip] Limited number of visibilities in AIPS ?

[Eric Greisen]

Arnaud Collioud wrote:
> Dear AIPS gurus,
> 
> I am wondering if there is a maximum number of visibilities for one AIPS UV file?
> 
> I am asking this because I am trying to put into AIPS the astrometric super-session which took place the 18 Nov 2009 for the International Year of Astronomy (IYA09). 35 stations observed during this 24-hour session, which means a lot of data.
> I got the following error when the file reached 5999454 visibilities... Is this just a coincidence or is 6 million the maximum ?
> 
>    1    3   08-JUN-2011  12:52:17     MK4IN      /data/2009_11_18_iya09/3308/323-0757 file name extract, #files=:0: 56:
>    1    8   08-JUN-2011  12:52:18     MK4IN     ZABORS: signal 11 received
>    1    8   08-JUN-2011  12:52:18     MK4IN     ABORT!
> 
> Best wishes,
> Arnaud
> 
> PS: I am using  AIPS 31DEC07

Grrrr - you should update although that will not affect MK4IN much is at 
all.  See http://www.aips.nrao.edu/ for AIPSLetters to tell you what you 
are missing.

There is no limit < 2**31-1 for the number of visibilities.

But that does not guarantee that MK4IN doesn't for example compute the 
required disk space in bytes with a 32-bit integer.  That would die 
fast.  This is a submitted task which I know little about but I will look.

How many random parameters are there?  How many Stokes, spectral 
channels, IFs?  Are you doing compressed or uncompressed format (COMPLEX 
axis is 1 or 3)?  Then I can see if you are close to the limit at 6 
million vis.

Eric Greisen