[daip] FRING on large (25Gb) line dataset problem

[Eric Greisen]

Kazi Rygl wrote:
> Dear Mark Greisen,
> 
> I encountered a problem with FRING when I run it on a large (25Gb) VLBI 
> line dataset.
> On smaller datasets it works fine. Also the problem is only there with 
> the TST version, not in the NEW version. I tried decreasing the solint 
> parameter but it didn't help (see suggestions of AIPS output below). 
> Setmaxap says:
>  >setmaxap(0)
> AIPS 2: SETMAXAP: current max dynamic AP is   528.000 Mbytes
> AIPS 2: SETMAXAP: allowed range is  20 to  1536 Mbytes
> 
> Since I'm not sure why FRING crashes (local problems, or due to 
> something in the program) I thought I just report it. Last week I could 
> run FRING with similar inputs without any problems.
> I paste the output of AIPS below together with my inputs.
> 
> Best regards,
>  Kazi
> 
> 
> 
> 
> FRING2: Task FRING  (release of 31DEC11) begins
> AIPS 2: Resumes
>  >FRING2: Set integration time to  1.000000 seconds, hope that is ok
> FRING2: UVGET: Using flag table version   1 to edit data
> FRING2: Selecting, editing and calibrating the data
> FRING2: Dividing data by source flux densities
> FRING2: Determining solutions
> FRING2: Writing SN table    3
> FRING2: Time=   0/ 20 58 30, Polarization = 1
> FRING2: QINIT: did a GET  of    135168 Kwords, OFF       -328032033
> FRING2: DID NOT GET WHAT I NEED FOR MEMORY
> FRING2: USE SETMAXAP TO RAISE THE LIMIT, OR
> FRING2: FRNALL: DYNAMIC MEMORY AP FAILS
> FRING2: FRNALL: MEMORY TOO SMALL FOR SPECIFIED FFT SEARCH
> FRING2: REDUCE DELAY AND/OR RATE WINDOW OR AVERAGE IN
> FRING2: FREQUENCY OR USE A SHORTER SOLINT
> FRING2: Purports to die of UNNATURAL causes
> FRING2: mcn3 31DEC11 TST: Cpu=     18.9  Real=     35  IO=     24974
> 
> task 'fring'
> inclass 'linec'
> anten 0
>  timera    0 20 57 01 0 20 59 59
>  cals     'J2038+5119'
>   docal    2 
>  snver    0
>  flagve   1
>  bif      0
>  eif      0
>  aparm    0
>  dparm    0
>  aparm(1) 2
>  aparm(9) 1
>  dparm(8) 1
>  solint  5
>  go;wait

FRING uses a large amount of dynamic memory both in the "pseudo-AP' and 
outside it.  The pseudo AP is limited by the parameter which you may 
change with SETMAXAP.  Try HELP SETMAXAP to show the considerations.
Recently, it was discovered that FRING asked for whatever it needs based 
on rate and delay windows, SOLINT, data integration time, etc.  But 
FRING did not test that it was given what it expected and went ahead as 
if all was well.  When it wanted more than SETMAXAP allowed it was given 
the max - 2 Gbytes (0.5 Giga words) in your case.  I added tests in 
FRING to make sure it got what it needed so that it would not wander off 
in dynamic memory writing over memory used for other purposes or even 
memory not allowed to the task.  ABORTs for such issues come later and 
are very confusing.

Try SETMAXAP 1024 to change the allowed upper limit and rerun your FRING.

Eric Greisen