[Numpy-discussion] Building Numeric with a native blas ?

Mats Klingberg mklingberg at spray.se
Sun Aug 1 04:14:02 EDT 2004

I recently did this under Gentoo. It seems that the atlas package doesn't 
build a complete lapack, which is necessary. Instead I emerged the newer 
blas-atlas and lapack-atlas packages. These build a complete lapack library 
with atlas optimizations. They are however masked with ~x86 so you have to 
add the following to your /etc/portage/package.keywords:

app-sci/lapack-atlas ~x86
app-sci/blas-atlas ~x86
app-sci/blas-config ~x86
app-sci/lapack-config ~x86

blas-config and lapack-config are packages that are needed by the other ones. 
They can be used to switch between reference lapack or atlas optimized 
libraries (if you install lapack-reference and blas-reference)

For more information see Gentoo bug #30453

Hope this helps,

On Friday 30 July 2004 18.28, Chris Barker wrote:
> David M. Cooke wrote:
> > Atlas might have installed a liblapack, with the (few) functions that it
> > overrides with faster ones. It's by no means a complete LAPACK
> > installation. Have a look at the difference in library sizes; a full
> > LAPACK is a few megs; Atlas's routines are a few hundred K.
> OK, I'm really confused now. I got it working, but it seems to have
> virtually identical performance to the Numeric-supplied lapack-lite.
> I'm guessing that the LAPACK package I emerged does NOT use the atlas BLAS.
> if the atlas liblapack doesn't have all of lapack, how in the world are
> you supposed to use it? I have no idea how I would get the linker to get
> what it can from the atlas lapack, and the rest from another one.
> Has anyone done this on Gentoo? If not how about another linux distro, I
> don't have to use portage for this after all.
> -Chris

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