[daip] FRING memory requirements
Ingyin Zaw
iz6 at cosmo.nyu.edu
Tue May 12 18:27:29 EDT 2009
Hi Amy,
Sorry for the confusion. Yes, the multiband delays are for geodetic
calibration and I don't need that many channels. The channel settings were
just set to be the same as the astronomy block. However, the problem was
that when I ran BPASS on the AVSPC file, I saw ringing whereas I didn't
see ringing from BPASS in the unaveraged file (using POSSM). This is why I
tried to use the 256-channel file even though I would prefer to use the
32-channel file (from my other email thread). However, it turns out that
when I apply BP with doband 1 in POSSM, it shows ringing but if I apply it
with SPLAT and look at the result, there is no ringing. So, I think I can
go ahead with the averaged file.
Thanks,
Ingyin
On Tue, 12 May 2009, Amy Mioduszewski wrote:
> Hi Ingyin,
>
> So I am confused about what you are trying to do. Why do you need multiband
> delays? I assumed you are trying to do a geodetic type calibration. For
> this you need calibrators observed all over the sky and would not need to
> observe those with narrow channels.
>
> Amy
>
> Ingyin Zaw wrote:
>> > Ingyin Zaw wrote:
>> > > On Thu, 7 May 2009, Eric Greisen wrote:
>> > >
>> > > > Ingyin Zaw wrote:
>> > > > > Hello,
>> > > > > > > I checked setapmax. It was set to 528 Mbytes. I changed it
>> > > to the > > maximum
>> > > > > allowed:
>> > > > > > setmaxap(0)
>> > > > > AIPS 1: SETMAXAP: current max dynamic AP is 6144.000 Mbytes
>> > > > > AIPS 1: SETMAXAP: allowed range is 20 to 6144 Mbytes
>> > > > > > > I still get the same memory error as below.
>> > > > > > > The fring parameters I've set (which are not defaults) are:
>> > > > > calsour '2145+067'
>> > > > > refant 6
>> > > > > solint 0
>> > > > > aparm 3 0 0 0 2 0
>> > > > > dparm 3 1 1 4.1 0
>> > > > > > > (docalib -1; flagver 0; doband -1).
>> > > > > > > Thanks,
>> > > > > Ingyin
>> > > > > > > > > > > On Wed, 6 May 2009, Eric Greisen wrote:
>> > > > > > > > Ingyin Zaw wrote:
>> > > > > > > Hello,
>> > > > > > > > > > > I'm trying to run FRING with aparm(5)=2 to solve
>> > > for multiband > > > > and single
>> > > > > > > band delays on a file with 256 channels and 8 IFs
>> > > (experiment > > > > BK114A). I
>> > > > > > > get the following error.
>> > > > > > > > > > > FRING1: Task FRING (release of 31DEC09) begins
>> > > > > > > FRING1: You are using a non-standard program
>> > > > > > > FRING1: Doing no flagging this time
>> > > > > > > FRING1: Selecting the data
>> > > > > > > FRING1: Dividing data by source flux densities
>> > > > > > > FRING1: Determining solutions
>> > > > > > > FRING1: Doing Least Squares fits for multi- and
>> > > single-band > > > > FRING1: delays
>> > > > > > > FRING1: Writing SN table 1
>> > > > > > > FRING1: Time= 0/ 02 28 14, Polarization = 1
>> > > > > > > FRING1: QINIT: did a GET of 5120 Kwords, OFF > > > >
>> > > FRING1: 11963214967809
>> > > > > > > FRING1: FRNSRC: MEMORY TOO SMALL FOR SPECIFIED FFT SEARCH
>> > > > > > > FRING1: REDUCE DELAY AND/OR RATE WINDOW OR AVERAGE IN
>> > > > > > > FRING1: FREQUENCY OR USE A SHORTER SOLINT
>> > > > > > > FRING1: Purports to die of UNNATURAL causes
>> > > > > > > FRING1: rglinux9 31DEC09 TST: Cpu= 0.9 Real= 1
>> > > > > > > IO= 86
>> > > > > > > AIPS 1: Resumes
>> > > > > > > AIPS 1: RETURN CODE 2 RECEIVED: STOPPING
>> > > > > > > > > > > I have set dparm 3 1 1 4.1 0. It seems strange
>> > > that it fails for > > > > such a
>> > > > > > > small search window. It fails even when the search window
>> > > is set > > > > to 0.1
>> > > > > > > nsec and 0.1 mHz. I'm not applying any calibrations or
>> > > bandpass.
>> > > > > > > > > > > I'm running 31 DEC 09, 64 bit AIPS on a machine
>> > > with following
>> > > > > > > specifications:
>> > > > > > > Linux rglinux9.cfa.harvard.edu 2.6.18-128.1.1.el5 #1 SMP
>> > > Mon Jan > > > > 26
>> > > > > > > 13:58:24 EST 2009 x86_64 x86_64 x86_64 GNU/Linux
>> > > > > > > > > > > I have seen the same problem on 31 DEC 09, 32 bit
>> > > AIPS as well > > > > on an
>> > > > > > > experiment with 512 channels and 8 IFs (BB242D).
>> > > > > > > > > > > I have made a FITS file of only the source I used
>> > > for FRING for > > > > testing.
>> > > > > > > It's available by ftp from cfa-ftp.harvard.edu,
>> > > > > > > User = anonymous, password = <youremailaddress>.
>> > > > > > > The file is located at: incoming/lincoln/BK114A_2145.FITS
>> > > > > > > > > > > Please let me know what I can do to be able to run
>> > > FRING with > > > > aparm(5)=2.
>> > > > > > Needless to say FRING should not do this - I note that it
>> > > only > > > asked for 20 Megabytes of AP memory. It is supposed to
>> > > ask for > > > what it actually needs if you allow it to do so. Have
>> > > you run > > > SETMAXAP with a small limit? I would recommend set
>> > > your max AP to > > > 0.5 or 1 Gbyte on your 64-bit computer.
>> > > > > > > > > If that does not work, send me your inputs and we will
>> > > fetch the > > > file and look at the problem.
>> > > > > > > > > Eric Greisen
>> > > > > > > > > > You have asked for an FFT on the frequency axis of
>> > > length 131072 or > perhaps it is 524288 - I do not know the details
>> > > enough to be sure.
>> > > > AIPS now does FFTs up to 32768 and we have no plans to allow
>> > > larger in > the near term. I will repair the error message which now
>> > > is only about > allowed size of FFTs (it used to mean what it says)
>> > > and repair the limit > in FRING which is currently lower than it has
>> > > to be. But that will not > allow you to do what you are trying to
>> > > do. There are aips memos which > describe what you should do to
>> > > accomplish what you need to accomplish.
>> > > I tried to reproduce the 131072 number and come up short. I have an
>> > > experiment (BK114A, 256 channels, 8 IFs) with 500 MHz total
>> > > bandwidth with
>> > > ~ 60 kHz channels which would seem, at most, to have a frequency
>> > > axis of
>> > > length 16384. Even for 512 channels and 8 IFs, I get a frequency axis
>> > > of
>> > > length 32768, which is within AIPS capabilities. Could you point out
>> > > where
>> > > my calculations are different from yours.
>> > >
>> > > > See the aips web page:
>> > > > http://www.aips.nrao.edu/
>> > > > and read AIPS Memo 110.
>> > > > > You will need to run FRING an IF at a time effectively and then
>> > > solve > for multi-band delay with MBDLY.
>> > > Thanks for pointing me to the memo. It says that FRING with aparm(5)=2
>> > > is
>> > > better than aparm(5)=0 + MBDLY when sources are weaker. We observe at
>> > > 22
>> > > GHz and our calibrators are relatively weaker, so we'd like the option
>> > > of
>> > > running with aparm(5)=2, if possible.
>> > >
>> > > > Eric Greisen
>> > > >
>> > > Thanks,
>> > > Ingyin
>> > >
>> > > _______________________________________________
>> > > Daip mailing list
>> > > Daip at listmgr.cv.nrao.edu
>> > > http://listmgr.cv.nrao.edu/mailman/listinfo/daip
>> > >
>> > Hi Ingyin,
>> >
>> > I am coming into this late so I apologize if don't understand something.
>> > How weak are your calibrators? If your calibrators are weak wouldn't it
>> > be better to average some channels? Why do you need 512 channels
>> > anyway? The multiband delay is looking at the delay between the IFs, the
>> > singleband delay is not calculated.
>> >
>> > Amy
>> Hi Amy,
>>
>> I'm observing H20 masers at 22 GHz. I have so many channels (256 in the
>> current dataset) because the maser lines are only ~1 km/s wide. I did
>> average 8 channels using AVSPC but was getting ringing when I applied a BP
>> table. That problem seems to be resolved now so I can run FRING with
>> aparm(5)=2 on the averaged file (with 32 channels).
>>
>> Thanks,
>> Ingyin
>>
>
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