Re: [Numpy-discussion] Eigenvalues hangs

[Sasha <nd...@ma...>]

Sorry for an empty message.  I lost connection and a half a page
message with it :-(

Here is a brief summary:

-ffloat-store may be expensive:

"""
Reading the gcc documentation, one finds that the -ffloat-store is an
expensive hack to attempt to avoid the excess precision in the floating
pointer registers on Intel FPUs.  Based on recent experience with
DONLP2, a noteworthy nonlinear solver, using -ffloat-store everywhere is
an unnecessarily costly workaround.
"""
<http://www.octave.org/octave-lists/archive/octave-maintainers.2004/msg0082=
5.html>

If it has to be enabled, it should be limited to dlapack_lite .

Red Hat patched its own lapack by disabling optimization for a few routines=
:

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=3D138683

-- sasha





On 1/23/06, Sasha <nd...@ma...> wrote:
> On 1/23/06, Sasha <nd...@ma...> wrote:
> > I think this issue was altimately resolved as a lapack rather than gcc
> > problem and -ffloat-store is not the right work-around.  I don't have
> > the right references right now, so unless someone steps in I will
> > follow up when I get home this evening.
> >
> > -- sasha
> >
> > On 1/23/06, S=E9bastien Boisg=E9rault <boi...@is...> wrote:
> > >
> > > Hi all,
> > >
> > > Robert Kern suggested to transfer a discussion that originated
> > > on comp.lang.python to this mailing-list.
> > >
> > > My problem is that on my platform the numpy 'eigenvalues' method
> > > hangs forever.
> > >
> > > Some platform info:
> > >     * numpy 0.9.4 (from the tar.gz)
> > >     * Linux Mandriva (gcc 4.0.1).
> > >     * no optimized BLAS version used.
> > >
> > > Greg Landrum pointed out that it may be a gcc 4.0 related problem and
> > > proposed a workaround -- to add the option '-ffloat-store' to CFLAGS.
> > >
> > > Could anybody tell me how I should modify the numpy sources to test
> > > this workaround ?
> > >
> > > Regards,
> > >
> > > SB
> > >
> > >
> > >
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