Bug#552429: [Pkg-openmpi-maintainers] Bug#552429: MPI: fix alternatives mess with runtime environment

[Manuel Prinz]

On Tue, 2009-11-10 at 15:29 -0600, Pavan Balaji wrote:
> MPICH2 and Open MPI should have the same priority, isn't it? They are
> just alternative implementations of MPI.

Thought about that too but I am unsure how update-alternatives handles
that case. The man page talks about only taking action if a priority is
higher than the other. It does not mention the special case where they
are equal. I did not want to lower MPICH2's importance or something like
that; just to have distinct values so I can avoid the need to fix
update-alternatives related bugs (again). ;)

> mpiexec and mpirun are the same even in MPICH2. mpiexec is required by
> the MPI standard, so all implementations provide it. mpirun is just kept
> around for backward compatibility since the MPI-1 days.

I was not aware of that. So maybe using "mpiexec" as the master
alternative might be better/more intuitive?

> I think there's a lot of confusion about MPICH2 on this email thread.
> I'll be happy to clarify any questions.

Not sure if it's specifically about MPICH2. My feeling is that it's more
of the general character of dealing with multiple MPI implementations
inside the distribution.

Best regards
Manuel