On Jan 4, 11:01 pm, mabshoff <[EMAIL PROTECTED]
dortmund.de> wrote:
> On Jan 4, 10:54 pm, jara <[EMAIL PROTECTED]> wrote:
>
> > On Jan 4, 5:38 pm, mabshoff <[EMAIL PROTECTED]
>
> > dortmund.de> wrote:
>
> > > Hi jara,
>
> > > you are correct.The problem is that we build the binaries on a
> > > relative modern CPU and hence the binaries cause problems on CPUs like
> > > yours. The solution is to build from source. We plan to build on older
> > > CPUs in the future, but haven't gotten the needed hardware yet.
>
> > > Cheers,
>
> > > Michael
>
> Hi,
>
> > Hi,
> > I think you just need to pass -march=i686 to the gcc when building the
> > precompiled
> > "i686" binaries, as imho everyone else does.
>
> the problem is ATLAS which is a tuned BLAS/Lapack library that gets
> you maximum performance for a given CPU type. If you have ATLAS
> libraries from your distribution you can try replacing the ones in
> $SAGE_LOCAL/lib. Those would be
>
> libatlas.a, libatlas.so, libcblas.a, libcblas.so, libf77blas.a and
> libf77blas.so
>
> Compiling ATLAS with  -march=i686 wouldn't work and destroy the
> performance advantage of using it in the first place. It is a trade
> off we did make and hopefully we will have more generic binaries soon.
>

Hello,
I replaced the libraries with ones from my distribution and sage now
works :-)

But regarding the precompiled downloads there are imho 3 options what
to do:
1. don't mark binaries as "i686" because they aren't i686-compatible.
Mark them as Pentium4 (i886??) or something.
2. recompile for i686 and sage will run slowly but it will at least
run. Place a notice in a README that recompilation from sources is
highly recommended for the best performance (remember Gentoo ;-)
3. provide several compiled versions of atlas - each compiled for
different architecture - and select the best one on installation. For
example Fedora 8 has following packages of atlas:
atlas.i386                               3.6.0-12.fc8           fedora
atlas-3dnow.i386                         3.6.0-12.fc8           fedora
atlas-sse.i386                           3.6.0-12.fc8           fedora
atlas-sse2.i386                          3.6.0-12.fc8           fedora


Thanks for your help,
-- Jara

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