[Difx-users] baseline-selective merge of two DiFX runs?

[Jan Wagner]

Thanks for the suggestions Adam!

Didn't know about the merge capability in difx2fits!

Now I added a new 'stripantennaDiFX.py' to DiFX trunk.

It will strip all unwanted baselines (or keep all wanted baselines).
That step seems to work. Now I still need to test how well the
outputs merge in difx2fits.

cheers,
Jan

Am 08.01.2018 um 11:42 schrieb Adam Deller:
> Hi Jan,
>
> I don't think so.  difx2fits automatically merges, but you don't
> have fine-grained control over baseline inclusions/exclusions.  An
> easy way might be to operate on the filesets themselves and just
> strip all Effelsberg baselines from the first fileset and all
> non-Effelsberg baselines from the second fileset (could you do
> that with your difx2difx script?) and then let difx2fits do the
> actual merge for you?  Otherwise a simple hacky merge is probably
> easy, a nice general difxMerge might be tricky.
>
> Cheers,
> Adam
>
> On 8 January 2018 at 21:02, Jan Wagner <jwagner105 at googlemail.com
> <mailto:jwagner105 at googlemail.com>> wrote:
>
>     Hi,
>
>     we're in a situation where we have two DiFX output data sets:
>
>     set 1 all stations present but one station (Eb) with VEX $FREQ
>     incorrect
>
>     set 2 some stations (Kt Ku Ky Mh) lost as their data were erased,
>     but Eb VEX $FREQ corrected
>
>     The correlator settings v2d and the .input files are identical
>     between these two sets.
>
>     I'd like to copy the visibilities from these two sets into a new
>     "merged" output set. Essentially, take set 1, ignore all
>     visibilities from baselines to Eb, and if set 2 has data on that
>     particular baseline to Eb then copy those visibilities from set 2.
>     This would produce a new correlator output dataset where the
>     maximum
>     number of baselines have good visibility data, except of course of
>     the irrecoverable baselines (Eb) x (Kt Ku Ky Mh).
>
>     Presumably this would be a trivial merge operation based upon the
>     baseline tag of each visibility data record in pairs of
>     .difx/DIFX_*
>     files.
>
>     But before I rush off and create a merging script in Python:
>
>     Does anyone know of (or have :-)) a "mergeDiFX.py" or similar
>     script
>     that does this trick?
>
>     kind regards,
>     Jan
>
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> -- 
> !=============================================================!
> Dr. Adam Deller         
> ARC Future Fellow, Senior Lecturer
> Centre for Astrophysics & Supercomputing 
> Swinburne University of Technology    
> John St, Hawthorn VIC 3122 Australia
> phone: +61 3 9214 5307
> fax: +61 3 9214 8797
>
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