[petsc-users] petsc compiled without MPI

[Satish Balay]

On Sun, 26 Feb 2023, Pierre Jolivet wrote:

> 
> 
> > On 25 Feb 2023, at 11:44 PM, Long, Jianbo <jl7037 at mun.ca> wrote:
> > 
> > Hello,
> > 
> > For some of my applications, I need to use petsc without mpi, or use it sequentially. I wonder where I can find examples/tutorials for this ?
> 
> You can run sequentially with just a single MPI process (-n 1).

even if you build with mpich/openmpi - you can run sequentially without mpiexec - i.e:

./binary

One reason to do this [instead of building PETSc with --with-mpi=0] - is if you are mixing in multiple pkgs that have MPI dependencies [in which case - its best to build all these pkgs with the same mpich or openmpi - but still run sequentially].

Satish

> If you need to run without MPI whatsoever, you’ll need to have a separate PETSc installation which was configured --with-mpi=0
> In both cases, the same user-code will run, i.e., all PETSc examples available with the sources will work (though some are designed purely for parallel experiments and may error out early on purpose).
> 
> Thanks,
> Pierre
> 
> > Thanks very much,
> > Jianbo Long
> 
>