iraf.net

General IRAF :: RE: segmentation error on stsdas' histogram

massey — Sat, 04 Feb 2012 00:04:55 GMT

Author: massey
Subject: Yep, that fixed it for me, too!
Posted: Sat Feb 04, 2012 12:04 am (GMT 0)

Thanks!

Systems :: RE: Iraf 2.15 Linux 32bit install

fitz — Fri, 03 Feb 2012 06:31:03 GMT

Author: fitz
Posted: Fri Feb 03, 2012 6:31 am (GMT 0)

I think the problem is in how the iraf.lnux.x86.tar.gz file was built, i.e. it includes only the 'bin.linux' directories and not the 'bin.redhat' symlinks that point to bin.linux. The install script determines the platform architecture by looking for a /etc/redhat-release file (Fedora is a derivative of redhat), however the 'cl' command script uses the more generic output of 'uname' and so comes up with linux as the architecture. If the symlinks were present (as in the combined iraf-linux.tar.gz files) then this difference doesn't matter.

I'll fix the distribution for the next release, until then you can just do

ln -s bin.linux bin.redhat

in the $iraf and $iraf/noao directories.

General IRAF :: RE: segmentation fault for interactive overscan correction

fitz — Fri, 03 Feb 2012 06:03:01 GMT

Author: fitz
Posted: Fri Feb 03, 2012 6:03 am (GMT 0)

Can you please post a sample image to the anonftp at ftp://iraf.noao.edu/pub so we can try to reproduce the problem? A bug was recently fixed that affects FITS files with 32-bit ints and bscale/bzero values that might explain it, or it could simply be an old version of SciSoft being used. The IRAF version and any other information you can provide would also help.

General IRAF :: RE: segmentation error on stsdas' histogram

fitz — Fri, 03 Feb 2012 05:53:47 GMT

Author: fitz
Posted: Fri Feb 03, 2012 5:53 am (GMT 0)

The problem was that the metacode stream was being written to stdgraph with a control packet header containing a 32-bit descriptor number (because the HISTOGRAM task is still a 32-bit binary), but was being read in the 64-bit CL as a 64-bit integer, corrupting the stream and creating an invalid descriptor. This has now been fixed for the next release but you can get a patched ECL binary from

ftp://iraf.noao.edu/iraf/v215/support/macintel/ecl.e
ftp://iraf.noao.edu/iraf/v215/support/linux64/ecl.e

The fix was to explicitly write the descriptor number as a 32-bit integer in order to be backwards compatible. For PyRAF graphics that might use the GKI directly, note that the descriptor number is still (in the current 64-bit binaries) being written as an 8-byte value. If it hasn't caused a problem so far you probably don't need to worry about it.

Anyway, HISTOGRAM now works as expected.

Systems :: RE: reading fits files with 64 bit SPP

fitz — Fri, 03 Feb 2012 05:39:08 GMT

Author: fitz
Posted: Fri Feb 03, 2012 5:39 am (GMT 0)

I'm looking into. It is a 64-bit problem in the IMIO interface, not a bug in your code. Will post a summary when it is tracked down.

General IRAF :: segmentation fault for interactive overscan correction

ewehner — Thu, 02 Feb 2012 21:37:33 GMT

Author: ewehner
Subject: segmentation fault for interactive overscan correction
Posted: Thu Feb 02, 2012 9:37 pm (GMT 0)

Hi,

I'm working on some mosaic data and trying to do the overscan correction interactively. Everything works fine when I have it do this correction silently, and the images display fine (both with mscdisplay and one chip at a time with display). But when I set "interactive" to "yes" I suddenly get a segmentation fault. Imexam works fine, but mscexam won't pop up the "green" screen... this also gives a segmentation error.

Popping up that green screen in mscred seems to be the problem, but I'm not sure what to fix. I am using an intel mac. I read about some other segmentation fault errors, and tried setting IRAFARCH to macosx, but this causes iraf to panic when I try to run ccdproc. Also, "dir" does show the files, so I'm thinking this may not be the problem. I'm running iraf that was installed via Scisoft, and its default seems to be to set the IRAFARCH parameter to macintel.

Any advice? Thanks in advance.

General IRAF :: RE: segmentation error on stsdas' histogram

fitz — Thu, 02 Feb 2012 20:02:36 GMT

Author: fitz
Posted: Thu Feb 02, 2012 8:02 pm (GMT 0)

But weren't those related to PyRAF graphics? This is the first I remember hearing about problems with 'pipes' or the CL?

General IRAF :: RE: segmentation error on stsdas' histogram

Mark S. — Thu, 02 Feb 2012 19:27:36 GMT

Author: Mark S.
Posted: Thu Feb 02, 2012 7:27 pm (GMT 0)

fitz wrote:

Gee, it woulda been great if somebody had told me about these .....

I did. You sent me patched binaries that worked. :) The protocol doesn't look very complicated, so I thought we found them all.

I have a couple of open tickets around this problem. They all have to do with graphics. When you run a regular task, there is just text being passed in the packets in the pipe. I wonder if graphics use a binary format, so there is a level 2 binary protocol that might still have a bug relating to the size of some data item. This histogram crash was because of a floating point exception of some kind, which is consistent with my hypothesis. That's as far as I got with this problem, though.

General IRAF :: RE: segmentation error on stsdas' histogram

fitz — Thu, 02 Feb 2012 19:19:02 GMT

Author: fitz
Posted: Thu Feb 02, 2012 7:19 pm (GMT 0)

Quote:

The fact that this fix works suggests to me that this is probably a bug in the handling of the pipe between CL and the tasks. We found some of these when IRAF 2.15 was still in alpha, but maybe there are still more.

Gee, it woulda been great if somebody had told me about these .....

With this clue I can confirm the message is coming from the CL not the task binary. Will fix it for the next release.

General IRAF :: RE: segmentation error on stsdas' histogram

Mark S. — Thu, 02 Feb 2012 18:58:34 GMT

Author: Mark S.
Posted: Thu Feb 02, 2012 6:58 pm (GMT 0)

I find that if I

setenv IRAFARCH macosx

before I start CL, I have no problems. This causes it to run the 32 bit CL. Most users won't notice the difference between the 32/64 bit system.

The fact that this fix works suggests to me that this is probably a bug in the handling of the pipe between CL and the tasks. We found some of these when IRAF 2.15 was still in alpha, but maybe there are still more.

b.t.w. The STScI statement about 64 bit IRAF is available at http://www.stsci.edu/resources/software_hardware/stsdas/iraf64