OpenBLAS binary packages

[Nicolas Pavillon]

> On May 15, 2019, at 22:04, Chris Jones <jonesc at hep.phy.cam.ac.uk> wrote:
> 
> 
>> Now that OpenBLAS became more widely used and is now a dependency for several other ports, I could look into making a ‘generic’ version as suggested, if it is considered preferable to reduce the building time at the cost of performance.
>> I would have to confirm if a generic version could also be made, as there have also been issues with build failures with older architectures.
> 
> I suspect it would be fairly easy to do. The portfile now has in it settings to enable AVX/AVX2 etc., via the NO_AVX=1 flags. You would just need to always pass this in the default build, and only (conditionally) remove them when a non-default 'native' variant is enabled…

Sure. I am just being a little bit paranoid, as on one hand, we are forcing certain compilation flags, while still relying on the automatic detection of the CPU architecture, and we got several tickets recently where this detection was not working as it was supposed to be, mostly for older machines. But it would indeed probably be all right. 

Also, it comes down to what should be considered a ‘generic’ version. Cutting down all AVX instructions would imply a significant loss in performance, even though probably that a large majority of computers can handle these, but I guess it would be pretty hard to avoid that, so that we would have to settle for the least common denominator. 

Cheers,

Nicolas