Re: Warning about BLAS choice and math/arpack-ng (needed for math/octave).

["Dr. Thomas Orgis" <thomas.orgis%uni-hamburg.de@localhost>]

Am Wed, 23 Jun 2021 13:55:31 -0400
schrieb Greg Troxel <gdt%lexort.com@localhost>: 

> As long as the build with no modifications works, that's the most
> important thing.

Yes. If you run with the default BLAS_TYPE=netlib, the FindCMake finds
libblas.so and is happy. It could also find libopenblas.so if you
installed that. This might be unexpected. You might want to pull up the
patch I am preparing right now to avoid this uncertainty.

But if you don't mess with the new BLAS packages, nothing changes.

> I would think cmake functions would be doing test compiles and thus work
> with bl3, but maybe not.

They don't know which library names to test for. FindBLAS.cmake has a
hardcoded list to test and only an interface to choose one of that list.

> The difficult thing to get right is minimum modifications to things not
> maintained in pkgsrc, with minimum breakage.   So heading to pkg-config
> might well make sense, from my fuzzy and pointy-haired view.

Let's see if CMake upstream agrees. Otherwise … how well would it work
to provide a blas.pc and lapack.pc in the wrapper environment? We could
place a long to openblas_pthread.pc in there and build with

CMAKE_ARGS+=	-DPREFER_PKGCONFIG=yes -DBLA_VENDOR=Generic

for it to use

  pkg_check_modules(PKGC_BLAS blas)

and find what we prepared.

Would that be easy? No modification at all to CMake or the packages,
just the wrapper placing a blas.pc and lapack.pc (and cblas.pc …).


Alrighty then,

Thomas

-- 
Dr. Thomas Orgis
HPC @ Universität Hamburg