[daip] Limited number of visibilities in AIPS ?

[Arnaud Collioud]

Le 8 juin 2011 à 16:34, Eric Greisen a écrit :

> 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.

Yes I know :) . Usually, I am using the latest version of AIPS on my laptop (mac os), but in this case, I am using the one installed on one of my lab server.
But an update is scheduled for September...
 

> 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.

The IYA09 session is like a normal IVS RDV session, excepted the number of participating stations.  This means I have:
* 1 polarisation (RR)
* 4 IFs at X-Band, 4 IFs at S-Band
* 16 spectra channels per IF (<-- I am not about this point)
* I am compressing the data (DOUVCOMP=1)

Thank you,
Arnaud