[SciPy-dev] CVS scipy.test() segfaulting on me on a Fedora2 box

Pearu Peterson pearu at scipy.org
Wed Dec 22 12:59:35 CST 2004



On Wed, 22 Dec 2004, Fernando Perez wrote:

> Charles Harris wrote:
>> Ok,
>> 
>> I've got the reorganized version from cvs and still don't get a segfault
>> using the distro BLAS and gcc 3.4.2.
>
> I suspect the problem lies with ATLAS.  I am using 
> atlas3.6.0_Linux_P4SSE2_2HT.tgz from the scipy website, which from reading 
> the included makefile, was built as follows:
>
>   F77 = /home/pearu/bin/g77
>   F77FLAGS = -fomit-frame-pointer -O -fno-second-underscore
>
> I think the problem is ATLAS, b/c the top of the backtrace I included 
> yesterday had this:
>
> #0  0x55cd67c2 in ATL_cdotc_xp0yp0aXbX ()
>    from /usr/lib/python2.3/site-packages/scipy/lib/lapack/flapack.so
>
> That first symbol is, I imagine, an ATLAS call.  But Pearu seems to have 
> built these binaries with pretty conservative flags (-O), and when you use 
> the distro BLAS (no ATLAS) you don't get any segfault.  So perhaps it's a bug 
> in ATLAS and/or g77 which appears even with basic optimizations.

Actually the Fortran lapack library that was used to complete ATLAS 
lapack, may have been compiled with -O3, I don't remember exactly anymore.
If somebody could confirm that compiling lapack library with -O2 will
fix the issue, then I'll look for rebuilding atlas binaries at scipy site.

Pearu




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