Re: LAPACK vs. OpenBLAS

[Eric Brown]

Ludovic Courtès <ludovic.courtes@inria.fr> writes:

> Hello!
> There are two cases:
>
>   1. Packages that depend on both ‘lapack’ and ‘openblas’.  This is
>      almost always a mistake because ‘openblas’ provides the same
>      interfaces as ‘lapack’, only with a more efficient implementation.
>
>   2. Packages that depend on ‘lapack’ only: for the same reason, they
>      should depend on ‘openblas’ instead.

My understanding is that Julia 1.6 (already released) requires 64-bit
BLAS, and openblas-ilp64 should do the trick.

There are scenarios where reference BLAS is more stable and/or
reproducible than optimized BLAS libraries.  Sometimes its lack of
knowledge of OpenBLAS and/or a numerical issue.

(cf. GNU R's discussion of which BLAS to use.)