[Difx-users] Question : What library/code is DiFX using to read VDIF files

[Adam Deller]

Yep, that'll be your problem, I suspect.  It shouldn't be too much work to
fix vdifio to understand legacy 16 byte headers, but it would be good to
only have to do it once.  I'd suggest that it might be best to fix vdifio
in DiFX, and then make sure that dspsr pulls this update (might need some
checking/coordination with Paul D).

If you want to do a real quick and dirty hack check, just change the
definition of VDIF_HEADER_BYTES from 32 to 16 locally and recompile.

If you get it going, would you be interested in making a better and more
permanent fix to VDIFIO?

Cheers,
Adam

On Fri, 20 Mar 2020 at 12:16, Stuart Weston <stuart.weston at aut.ac.nz> wrote:

> >> legacy (16 byte) headers?
>
>
>
> I think our chain (DBBC/Fila10G/Jive5ab) is producing 16byte headers.
>
>
>
> Well when I do a dumb read (python script) to check the data I have to use
> 16bytes
>
>
>
> Stuart Weston
>
>
>
> Mobile: 021 713062
>
> Skype: stuart.d.weston
> Email:  stuart.weston at aut.ac.nz
>
> http://www.atnf.csiro.au/people/Stuart.Weston/index.html
>
> Software Engineer
> Institute for Radio Astronomy & Space Research (IRASR)
> School of Engineering, Computer and Mathematical Sciences
> Faculty of Design and Creative Technologies
> Auckland University of Technology, New Zealand.
>
> http://www.irasr.aut.ac.nz/
>
>
>
> *From:* Adam Deller <adeller at astro.swin.edu.au>
> *Sent:* Friday, 20 March 2020 2:11 PM
> *To:* Stuart Weston <stuart.weston at aut.ac.nz>
> *Cc:* Phillips, Chris (CASS, Marsfield) <Chris.Phillips at csiro.au>;
> difx-users at listmgr.nrao.edu
> *Subject:* Re: [Difx-users] Question : What library/code is DiFX using to
> read VDIF files
>
>
>
> Hi Stuart,
>
>
>
> Is your VDIF data regular (32 byte) or legacy (16 byte) headers?  I'm
> pretty sure that the latter is known to be not supported by VDIFIO (a
> relatively simple fix, that should certainly be made at some stage...)
>
>
>
> Cheers,
>
> Adam
>
>
>
> On Fri, 20 Mar 2020 at 11:54, Stuart Weston <stuart.weston at aut.ac.nz>
> wrote:
>
> Thanks Adam,
>
>
>
> I am working with some code that Willem hacked together for DSPSR using
> Mark5Access.
>
>
>
> Trying to get it to use our single dish data recorded in vdif format from
> the DBBC/Fila10G/Jive5ab.
>
>
>
> Paul’s code doesn’t read our vdif ☹ data
>
>
>
> Stuart Weston
>
>
>
> Mobile: 021 713062
>
> Skype: stuart.d.weston
> Email:  stuart.weston at aut.ac.nz
>
> http://www.atnf.csiro.au/people/Stuart.Weston/index.html
>
> Software Engineer
> Institute for Radio Astronomy & Space Research (IRASR)
> School of Engineering, Computer and Mathematical Sciences
> Faculty of Design and Creative Technologies
> Auckland University of Technology, New Zealand.
>
> http://www.irasr.aut.ac.nz/
>
>
>
> *From:* Adam Deller <adeller at astro.swin.edu.au>
> *Sent:* Friday, 20 March 2020 1:50 PM
> *To:* Stuart Weston <stuart.weston at aut.ac.nz>
> *Cc:* Phillips, Chris (CASS, Marsfield) <Chris.Phillips at csiro.au>;
> difx-users at listmgr.nrao.edu
> *Subject:* Re: [Difx-users] Question : What library/code is DiFX using to
> read VDIF files
>
>
>
> Hi Stuart,
>
>
>
> mpifxcorr uses mark5access to unpack VDIF samples.  The vdifio library
> that is also included with DiFX is quite limited - apart from what Chris
> already noted, I believe it doesn't support legacy VDIF.  Without any
> disrespect to anyone who worked on it (including me :) ) it was really a
> fairly quick hack to support some simple utilities.
>
>
>
> Now, dspsr I think based some of its VDIF support code on vdifio.  Paul
> Demorest first made a copy of vdifio onto git - whether it ultimately
> became an external mirror of the vdifio hosted on SVN in DiFX or if it has
> branched off (and had functionality added) I'm actually not sure.
>
>
>
> I know dspsr is capable of processing the VDIF-formatted data produced by
> the VLA tied array system, so I'm pretty sure that unpacking is already
> available in dspsr somewhere!  I'd suggest checking with Paul Demorest,
> since he is definitely the key person for VDIF in dspsr.
>
>
>
> Cheers,
>
> Adam
>
>
>
> On Fri, 20 Mar 2020 at 10:32, Stuart Weston via Difx-users <
> difx-users at listmgr.nrao.edu> wrote:
>
> >> If your question is a licensing one
>
>
>
> Nope its not that.
>
>
>
> So I take it DiFX uses Mark5access, yes ?
>
>
>
> Stuart Weston
>
>
>
> Mobile: 021 713062
>
> Skype: stuart.d.weston
> Email:  stuart.weston at aut.ac.nz
>
> http://www.atnf.csiro.au/people/Stuart.Weston/index.html
>
> Software Engineer
> Institute for Radio Astronomy & Space Research (IRASR)
> School of Engineering, Computer and Mathematical Sciences
> Faculty of Design and Creative Technologies
> Auckland University of Technology, New Zealand.
>
> http://www.irasr.aut.ac.nz/
>
>
>
> *From:* Phillips, Chris (CASS, Marsfield) <Chris.Phillips at csiro.au>
> *Sent:* Friday, 20 March 2020 11:43 AM
> *To:* Stuart Weston <stuart.weston at aut.ac.nz>
> *Cc:* difx-users at listmgr.nrao.edu
> *Subject:* Re: [Difx-users] Question : What library/code is DiFX using to
> read VDIF files
>
>
>
> Hi Stuart
>
>
>
>
>
>
>
> Just wondering if we can use the DiFX VDIF library/code instead ?
>
>
>
>
>
> It is not clear what your question actually is.
>
>
>
> The initial VDIFIO library I wrote had *no* sampling unpacking routines.
> Others may had added some, I am not sure. Without that the answer would be
> essentially be no. VDIFIO is in no way a plug in replacement for
> mark5access.
>
>
>
> If your question is a licensing one, then yes as all of DFIX is GPLv3 now.
>
>
>
> Cheers
>
> Chris
>
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>
>
>
>
> --
>
> !=============================================================!
>
> A/Prof. Adam Deller
>
> ARC Future Fellow
>
> Centre for Astrophysics & Supercomputing
>
> Swinburne University of Technology
> John St, Hawthorn VIC 3122 Australia
>
> phone: +61 3 9214 5307
>
> fax: +61 3 9214 8797
>
>
>
> office days (usually): Mon-Thu
> !=============================================================!
>
>
>
>
> --
>
> !=============================================================!
>
> A/Prof. Adam Deller
>
> ARC Future Fellow
>
> Centre for Astrophysics & Supercomputing
>
> Swinburne University of Technology
> John St, Hawthorn VIC 3122 Australia
>
> phone: +61 3 9214 5307
>
> fax: +61 3 9214 8797
>
>
>
> office days (usually): Mon-Thu
> !=============================================================!
>


-- 
!=============================================================!
A/Prof. Adam Deller
ARC Future Fellow
Centre for Astrophysics & Supercomputing
Swinburne University of Technology
John St, Hawthorn VIC 3122 Australia
phone: +61 3 9214 5307
fax: +61 3 9214 8797

office days (usually): Mon-Thu
!=============================================================!
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