[bug #62607] Converting to TPV and then SIP crashes for some images

[Pedram Ashofteh Ardakani]

URL:
  <https://savannah.gnu.org/bugs/?62607>

                 Summary: Converting to TPV and then SIP crashes for some
images
                 Project: GNU Astronomy Utilities
               Submitter: pedram
               Submitted: Thu 09 Jun 2022 08:50:18 AM UTC
                Category: Fits
                Severity: 3 - Normal
              Item Group: Crash
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any


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Follow-up Comments:


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Date: Thu 09 Jun 2022 08:50:18 AM UTC By: Pedram Ashofteh Ardakani <pedram>
== Problem ==

I've tried converting between TPV and SIP multiple times. Usually it works
fine. But there are some cases that it won't work.

== Why I did this ==

Sometimes, opening the TPV image converted from SIP alongside another frame in
the *ds9* makes the program malfunction. One of the frames just shoots out of
the pane! I thought maybe the converted *WCS* has some bugs in it. 

Therefore, I tried converting multiple times to see if gnuastro might have
problems with the converted image too. For some images, it worked just fine no
matter how many times I converted the image back and forth. 

However, for the image attached below, that is not the case. I get the
following output:


$ astfits img-sip-tpv.fits -h1 --wcsdistortion SIP -o img-sip-tpv-sip.fits    
                                                  
gsl: svd.c:285: ERROR: svd of MxN matrix, M<N, is not implemented             
                                                                
Default GSL error handler invoked.                                            
                                                                
Aborted (core dumped)


* 'img-sip.fits' is the original image
* 'img-sip-tpv.fits' is the image converted from SIP to TPV
* 'img-sip-tpv-sip.fits' would be the image converted from SIP, to TPV, and
back to SIP: which fails

== What to expect ==

Not a core dump! A slight offset from the original SIP can be expected since
it is converted back and forth using multiplication and trigonometric
functions.

== Steps to reproduce ==


$ astfits img-sip.fits --wcsdistortion TPV -o img-sip-tpv.fits
$ astfits img-sip-tpv.fits --wcsdistortion SIP -o img-sip-tpv-sip.fits







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File Attachments:


-------------------------------------------------------
Date: Thu 09 Jun 2022 08:50:18 AM UTC  Name: img-sip.fits  Size: 17KiB   By:
pedram

<http://savannah.gnu.org/bugs/download.php?file_id=53287>
-------------------------------------------------------
Date: Thu 09 Jun 2022 08:50:18 AM UTC  Name: img-sip-tpv.fits  Size: 11KiB  
By: pedram

<http://savannah.gnu.org/bugs/download.php?file_id=53288>

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