CASA history is screwed up

Discussions on CASA for developers
fkbreitl
Posts: 4
Joined: Thu Feb 28, 2013 6:37 am

CASA history is screwed up

Postby fkbreitl » Thu Feb 28, 2013 6:43 am

In the history of my measurement set I found millions of entries like:

- Selecting data according to uvrange: setdata will reset this selection
- Allowed uv range: 0 to 1000 wavelengths
- By UVRANGE selection previously selected number of rows 314960 are now reduced to 160655
- [Defining image properties:nx=256 ny=256 cellx='40arcsec' celly='40arcsec' stokes=I' mode=MFS nchan=-1 start=0 step=0 spwids=[0] fieldid=-1 facets=1 frame=5 distance='0', phaseCenter='06:09:39.00, 23.25.08.00, ' mStart='Radialvelocity: 0' qStep='0 '' mFreqStart='Frequency: 0]
- Weighting MS: Imaging weights will be changed
- Uniform weighting: sidelobes will be suppressed over full image

According to my understanding these are just messages from CASA which do not modify the MS. Therefore they should not be there. The history should only contain information about changes done to the MS.

The current behavior is very problematic, since it e.g. requires write access to an MS for imaging, which should not be the case.
Moreover in case of time resolved imaging (an image per time step) the history gets flooded with useless information which is further exported to IMAGE and FITS files where it occupies 99% of the disk space and only leaves 1% for the actual images.

This behavior prevents the usage of CASA for time resolved imaging and therefore needs to change urgently.

kgolap
Posts: 4
Joined: Thu Sep 01, 2011 4:44 pm

Re: CASA history is screwed up

Postby kgolap » Thu Feb 28, 2013 12:42 pm

You can use an or multiple MS in read only mode if you use imager.selectvis to open the ms thus no history will be written.
http://casa.nrao.edu/docs/CasaRef/imager.selectvis.html

im.selectvis(vis='myms.ms',......,writeaccess=False)

If you want such control in clean then you should file a helpdesk ticket.

fkbreitl
Posts: 4
Joined: Thu Feb 28, 2013 6:37 am

Re: CASA history is screwed up

Postby fkbreitl » Thu Feb 28, 2013 1:55 pm

Hi Kumar,

Thanks for your answer.
First of all I am surprised, that "writeaccess" is not an option of im.open() where most people would expect it and where it would work for clean as well.
Second writing the unrelated info to the history of an MS which was not write protected still doesn't make sense and needs to change.
Nevertheless your suggestions seems to work as a temporary workaround. Thanks for the tip.
Do I still need to write a ticket to have somebody fix this?
What would also be needed is a switch to disable the history export to image and FITS files.

Cheers

Frank

logonutility
Posts: 1
Joined: Thu Nov 09, 2017 3:27 am
Location: Mumbai
Contact:

Re: CASA history is screwed up

Postby logonutility » Thu Nov 09, 2017 3:33 am

For NRAO is should be a challenge because CASA history is screwed up totally

juanca21
Posts: 2
Joined: Tue Dec 12, 2017 1:55 pm
Contact:

Re: CASA history is screwed up

Postby juanca21 » Tue Dec 12, 2017 1:56 pm

good information! thanks.


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