[HEADSUP] Atlas changed libraries

[Susi Lehtola]

On Mon, 30 Sep 2013 10:03:14 +0300
Susi Lehtola <jussilehtola at fedoraproject.org> wrote:
> On Sun, 29 Sep 2013 23:57:21 +0200
> Kevin Kofler <kevin.kofler at chello.at> wrote:
> 
> > Susi Lehtola wrote:
> > 
> > > On Sun, 29 Sep 2013 01:04:31 +0200
> > > Kevin Kofler <kevin.kofler at chello.at> wrote:
> > >> Susi Lehtola wrote:
> > >> > If you link to -lblas, you're shooting yourself in the leg in the first
> > >> > place, since that's the reference implementation on current Fedoras.
> > >> 
> > >> In fact, I noticed that, and that's a serious packaging bug.
> > >> 
> > >> If a package links -lblas -llapack, if ATLAS is installed, it'll get
> > >> reference BLAS and ATLAS LAPACK! If it links -llapack -lblas, it'll
> > >> probably get the ATLAS functions throughout, because then libatlas is
> > >> resolved first. That's very unexpected and broken behavior.
> > > 
> > > No, you're assuming nonstandard behavior. ATLAS has never done this.
> > 
> > I am describing the behavior that actually happens with the Fedora 18 (and I 
> > presume 19 too) atlas-sse2 package!
> > 
> > Try running ldd on LAPACK-using stuff, you'll see how the ATLAS liblapack is 
> > picked up (but libblas is not overridden, which is a bug).
> 
> Yes, but everyone knows that if you want ATLAS, the link command is
>  -L%{_libdir} -llapack -lf77blas -latlas
> If you link to -lblas you're assuming nonstandard behavior. Fedora is
> not Debian.
> 
> Nowadays this is just
>  -L%{_libdir} -lsatlas
> a much easier version.

.. and this is also the main reason why I think that the new scheme is
loads better. At the linking phase you can be 100% sure of what library
you're using, and also that you're not going to run into problems with
incompatible libraries.
-- 
Susi Lehtola
Fedora Project Contributor
jussilehtola at fedoraproject.org