[SciPy-user] Re: BLAS optimized matrix multiplication

Kirill Lapshin kir at lapshin.net
Tue Jun 1 13:03:44 CDT 2004

Pearu Peterson wrote:
> Scipy 0.3 win32 installer should use ATLAS 3.6.0 that is optimized for 
> PIII. Note that scipy.dot refers to Numeric/dotblas.dot function:
> In [1]: import scipy
> In [2]: scipy.dot.__module__
> Out[2]: 'dotblas'
> (at least on my debian box).

Well not on my Windows box. It says 'Numeric' here. I am using binary 
install from scipy.org, the one which claims that it comes with ATLAS 
3.6.0. I guess the problem is that Numeric binary package distributed by 
Numeric guys does not have dotblas compiled. That's what I was trying to 
say -- Numeric comes without ATLAS so they did not include dotblas, but 
you do distribute ATLAS on windows, so it would be natural for you to 
add dotblas in SciPy. I know that I can recompile Numeric and SciPy, but 
it would be nice if default install would do the right thing.

BTW, since you are using Debian, is there Debian package for SciPy? 
Looks like there is no official one yet, but maybe someone maintains 
unofficial? Any plans on official package?

> Scipy has linalg that contains wrappers to blas/lapack libraries and use 
> ATLAS when available. See 
>   dir(scipy.linalg.cblas)
>   dir(scipy.linalg.fblas)
>   dir(scipy.linalg.clapack)
>   dir(scipy.linalg.flapack)

Cool, thanks. x = scipy.linalg.fblas.dgemm(1,a,b) is much much faster 
than x = dot(a,b).

BTW, why cblas module is almost empty and fblas has all the wrappers? Is 
it safe to assume that fblas has the same set of routines on all 
platforms, or is it configuration specific?

> Yes, I think we should release 0.3.1 before summer.

It is summer already :)
Oh, wait, did you mean summer 2005? Just kidding.


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