[Numpy-discussion] Windows, blas, atlas and dlls

[Frédéric Bastien]

Hi,

We also have the same problem for Theano. Having one reusable blas on
windows would be useful to many project. Also, if possible try to make it
accesible from C,C++ too. Not just cython.

Fred
On Feb 20, 2013 5:15 AM, "Dag Sverre Seljebotn" <d.s.seljebotn at astro.uio.no>
wrote:

> On 02/20/2013 10:18 AM, Sergio wrote:
> > Dag Sverre Seljebotn <d.s.seljebotn <at> astro.uio.no> writes:
> >
> >>
> >> On 02/18/2013 05:26 PM, rif wrote:
> >>> I have no answer to the question, but I was curious as to why directly
> >>> calling the cblas would be 10x-20x slower in the first place.  That
> >>> seems surprising, although I'm just learning about python numerics.
> >>
> >> The statement was that directly (on the Cython level) calling cblas is
> >> 10x-20x slower than going through the (slow) SciPy wrapper routines.
> >> That makes a lot of sense if the matrices are smalle nough.
> >>
> >> Dag Sverre
> >
> > Soory for expressing myself badly.
> >
> > I need to call cblas directly from cython, because it is faster.
> >
> > I use matrix multiplication in a tight loop.
> >
> > Let the speed with the standard dot be 100,
> >
> > Speed using the scipy.linalg.blas routines is 200
> >
> > And speed calling directly atlas from cython is 2000
> >
> > Which is reasonable, since this avoids any type checking.
> >
> > The point is that I need to ship an extra atlas lib to do so in windows,
> > notwithstanding the fact that numpy/scipy incorporate atlas in the
> windows build.
> >
> > I was wondering if there is a way to build numpy/scipy with atlas
> dynamically
> > linked into it, in order to be able to share the atlas libs between my
> code and
> > scipy.
>
> You could also look into OpenBLAS, which is easier to build and
> generally faster than ATLAS. (But alas, not supported by NumPy/SciPY
> AFAIK.)
>
> Dag Sverre
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