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

[Maurice Brémond]

Hi Ludovic & Simon!

I agree, the *-mpich packages are not necessary and this asks the
question of why those variants and why not others. Finally, I could keep
them on my own channel for convenience.

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

In guix packages, mpi input is usually declared as
(("openmpi" . ,openmpi))
or
(("mpi" . ,openmpi))

So two flags are necessary for the transformation.

Doing this, I ran into problems with your patch...

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)

Invalid error code (-2) (error ring index 127 invalid)
INTERNAL ERROR: invalid error code fffffffe (Ring Index out of range) in 
MPID_nem_tcp_init:373
Fatal error in PMPI_Init: Other MPI error, error stack:
MPIR_Init_thread(586)..............: 
MPID_Init(224).....................: channel initialization failed
MPIDI_CH3_Init(105)................: 
MPID_nem_init(324).................: 
MPID_nem_tcp_init(175).............: 
MPID_nem_tcp_get_business_card(401): 
MPID_nem_tcp_init(373).............: gethostbyname failed, localhost (errno 0)

If I go into the build directory and launch the check manually after
sourcing the environment-variables file, it works...

So it seems that this is related to guix and the guixbuild environment in
the definition of the package.

Maurice