[Numpy-discussion] Dot product performance on python 2.6 (windows)

[josef.pktd at gmail.com]

On Fri, Sep 11, 2009 at 5:25 AM, David Cournapeau
<david at ar.media.kyoto-u.ac.jp> wrote:
> V. Armando Solé wrote:
>> David Cournapeau wrote:
>>
>>> V. Armando Solé wrote:
>>>
>>>
>>>> Hello,
>>>>
>>>> It seems to point towards a packaging problem.
>>>>
>>>> In python 2.5, I can do:
>>>>
>>>> import numpy.core._dotblas as dotblas
>>>> dotblas.__file__
>>>>
>>>> and I get:
>>>>
>>>> C:\\Python25\\lib\\site-packages\\numpy\\core\\_dotblas.pyd
>>>>
>>>>
>>>>
>>> That's where the error lies: if you install with nosse, you should not
>>> get _dotblas.pyd at all.
>>>
>> Why? The nosse for python 2.5 has _dotblas.pyd
>>
>
> Yes, and it should not - because the _dotblas.pyd uses SSE2
> instructions.  The python 2.6 installer is the correct one, python 2.5
> is not.
>> Is it impossible to get it compiled under python 2.6 without using sse2
>> or sse3?
>>
>
> It is possible to compile anything you want if you are willing to go
> through the hassle of compiling ATLAS on windows. The binary installer
> only uses ATLAS (and hence build _dotblas) for SSE2 and SSE3. The low
> availability of machines with only SSE does not worth the hassle to do
> it anymore (but again, that's only an issue of the official binaries,
> you can still compile your own atlas).
>

It's also possible to use the older ATLAS binaries at
http://www.scipy.org/Installing_SciPy/Windows#head-cd37d819e333227e327079e4c2a2298daf625624
with MingW, which does not require building ATLAS yourself.
I'm using the sse2 from there and don't have any problems.

David,
If you have updated ATLAS binaries (e.g. also for sse3), is it possible to add
them to the webpage?

Thanks,
 Josef


> cheers,
>
> David
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