[bug#39588] gnu: Add mpich, scalapack-mpich, mumps-mpich, pt-scotch-mpich, python-mpi4py-mpich

[zimoun <zimon.toutoune@gmail.com>]

Hi,

Thank you Maurice for the packages! :-)


On Mon, 17 Feb 2020 at 18:27, Ludovic Courtès <ludo@gnu.org> wrote:

> As for the “-mpich” packages: they look good to me, though I’m not
> entirely sure whether we should create “-mpich” variants for each of
> them.  Ideally ‘--with-inputs’ would be enough, but I don’t know.  At
> the same time, those variants don’t cost us much, so if they’re useful,
> why not.

Is it not related to "package parameters" or the discussion we had
about rebuilding everything with another compiler?
Other said, '--with-inputs' will do the job for explicit packages but
not the implicit ones.

One easy move should to generalize -- if possible -- what is done in
'with-python2' or 'with-ocaml4.07'. But I am not convinced it is easy
because it is clearly dependant on the build system.

On the other hand, I gave a look at spack (after the discussion at
FOSDEM) and how they do. The WIP branch [1] about the solver is
interesting: possibly catch incompatibilities earlier using solver
(SAT or other) and specifications. But I am not convinced neither it
is the way to go because it adds a lot of complexity for a gain that
could be discussed. ;-)


[1] https://github.com/spack/spack/tree/features/solver/lib/spack/spack/solver


Well, for these particular patches, the variants are ok.
But we should think about how to ease the variant generation of all the chain.


Cheers,
simon