[HEADSUP] Atlas changed libraries

Frantisek Kluknavsky fkluknav at redhat.com
Mon Sep 23 13:19:08 UTC 2013


On 09/23/2013 02:46 PM, Susi Lehtola wrote:
> Well, it's not too hard to understand why ATLAS does things the way it
> does. It's already in the acronym: Automatically Tuned Linear Algebra
> Software. You generate a library that is optimal for your processor. In
> comparison, GotoBLAS (OpenBLAS) has been hand-tuned in assembly for
> every supported CPU.
>
> On the other hand, I'm not sure why they don't just take their tool and
> pregenerate lists of optimal parameters for every available CPU. That
> way you could compile everything in the same package and do runtime CPU
> detection. Currently binary distributions have to do some hackaround to
> generate a reasonably efficient one-size-fits-all library.
>

Atlas has hand-tuned assembler kernels as well. Build-time tuning 
searches mainly for optimal block size to minimize cache misses. How 
does OpenBlas handle blocking?


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