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

[David Cournapeau]

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).

cheers,

David