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

[Ludovic Courtès]

Hi Maurice,

Thanks for the patches!  We like to have one patch per package, so I
started with MPICH:

Maurice Brémond <address@hidden> skribis:

> +(define-public mpich
> +   (package
> +     (name "mpich")
> +     (version "3.4a2")
> +     (source (origin
> +               (method git-fetch)
> +               (uri (git-reference
> +                     (url "https://github.com/pmodels/mpich";)
> +                     (commit "644051d13dc20aecd460ba3db088756659c3dad3") ; 
> tag v3.4a2
> +                     (recursive? #t)))
> +               (sha256
> +                (base32
> +                 "02ildr7wh40q1qaq5k8npb6vw6kv9szmrm3lspr6skqa5csmrrxw"))))

I ended up modifying the package:

  • To use 3.3 instead of 3.4a, the latter being listed as “alpha”;

  • To build from an official tarball rather than from a Git checkout,
    so that the GNU build system is already bootstrapped;

  • To ensure that the bundled copies of hwloc and ucx are not used.

I pushed the result here:

  
https://git.savannah.gnu.org/cgit/guix.git/commit/?id=c70261bfb993cebc23cd80042de3f52a8b7932a4

Let me know if I broke something.

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.

Thoughts, HPC folks?

Ludo’.