Re: RFC: building numpy against OpenBLAS.

[Ricardo Wurmus]

Federico Beffa writes:

> Out of curiosity, could you outline how OpenBLAS is optimized for a
> specific CPU architecture while being compiled on a different CPU (and
> hence allowing to be substituted)?

The Quick Install instructions[1] say that when OpenBLAS is compiled
with DYNAMIC_ARCH=1

   "All kernel will be included in the library and dynamically switched
    the best architecutre at run time."

It seems that unlike ATLAS, OpenBLAS does not perform any self-tuning
but relies on hand-optimised code (e.g. by using CPU-specific
instructions).

~~ Ricardo

[1]: 
https://github.com/xianyi/OpenBLAS/blob/80bf3e6a3525f558a9fde2514622313c991c091f/GotoBLAS_02QuickInstall.txt#L67