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

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

Hi Maurice,

On Wed, 19 Feb 2020 at 12:46, Maurice Brémond <Maurice.Bremond@inria.fr> wrote:

> >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.

Sorry for the confusion, because what I said is *wrong*.
It is not the definition of an implicit inputs. The definition is:

--8<---------------cut here---------------start------------->8---
In addition, this build system ensures that the “standard” environment
for GNU packages is available. This includes tools such as GCC, libc,
Coreutils, Bash, Make, Diffutils, grep, and sed (see the (guix
build-system gnu) module for a complete list). We call these the
implicit inputs of a package, because package definitions do not have to
mention them.
--8<---------------cut here---------------end--------------->8---


> Ok thank you for the clarification, I understand better now.
>
> I misunderstood the documentation:
>
> https://guix.gnu.org/manual/en/html_node/Package-Transformation-Options.html
>
>    --with-input=package=replacement
>    [...]
>    This is a recursive, deep replacement. [...]

Well, you understood correctly. It is me that mix and add confusion, sorry.


> In the scalapack input I can see:
>      `(("mpi" ,openmpi)
>        ("fortran" ,gfortran)
>        ("lapack" ,lapack)))             ;for testing only
>
> So my assumption is that the --with-input transformation should work
> here as neither gfortran or lapack depends on mpi and to just build
> scalapack with mpich I tried:
>
> guix time-machine --commit=c70261bfb993cebc23cd80042de3f52a8b7932a4 -- build scalapack --with-input=openmpi=mpich

Hum, my MUA trims the long message.


Well, my point was: maybe it does not work because of the implicit inputs.
Now, mpi has bitten me so I will try this afternoon. :-)

Cheers,
simon