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

[zimoun]

Hi Maurice,

On Tue, 18 Feb 2020 at 18:58, Maurice Brémond <address@hidden> wrote:

> If I understand, in this case, the usage of --with-input is
> possible because implicit packages are very likely to not use mpi ?

Maybe I miss the issue. I have not look at mumps and related since... years. :-)
(Neither your patches. :-D)

If mumps depends explicitly on openmpi, then '--with-inputs' can
rewrite the direct dependencies, by providing say mpich instead of
openmpi.
If petsc* depends explicitly on openmpi and on mumps (which depends
explicitly on openmpi too), then '--with-inputs=openmpi=mpich'  will
*only* rewrite the dependency of petsc but not of mumps. So it ends
with petsc compiled with mpich and mumps with openmpi.

Still considering this (fictive) example, where:
 - petsc depends on openmpi(1) and mumps
 - mumps depends on openmpi(2)
The openmpi(2) is an implicit dependency for petsc and '--with-inputs'
does not work.

*because I know better PETSc than Scotch. ;-)



> You can try with my original patch just a transformation of
> mumps-openmpi into mumps-mpich:
>
> guix time-machine --url=https://gitlab.inria.fr/bremond/guix.git \
>   --branch=add-mpich -- \
>   environment -K --pure --ad-hoc mumps-openmpi \
>   --with-input=mpi=mpich --with-input=openmpi=mpich --
>
> This works for me, I can use a similar command to compile and execute a
> program which uses mumps and I can see with ldd that mpich is used.
>
> Then with the current mpich patch on savannah master:
>
> guix time-machine --commit=c70261bfb993cebc23cd80042de3f52a8b7932a4 -- \
>   environment -K --pure --ad-hoc mumps-openmpi \
>   --with-input=mpi=mpich --with-input=openmpi=mpich --
>
> This fails on my machine for the pt-scotch check (there is the same
> error with scalapack check)

Are 'pt-scotch' and 'scalapack' compiled with 'mpich' or 'openmpi'?

Because maybe "mumps-openmpi --with-input=openmpi=mpich" compiles
'mumps' using 'mpich' as MPI but compile 'pt-scotch' or 'scalapack'
with the default implementation which seems 'openmpi'.


Thank you for your work.

All the best,
simon