Re: [Libmesh-users] libmesh with petsc and without MPI

[Roy S. <roy...@ic...>]

On Tue, 24 Feb 2009, STEPHANE TCHOUANMO wrote:

> I'd like to configure and compile LibMesh with PETSc and without MPI but it seems to me that its not possible.
> When i do: " ./configure --enable-petsc --without-mpi " i always get a configuration without MPI but with Laspack.
> The option "--enabled-petsc" can only be valid with MPI even if Petsc has been compiled without MPI.
>
> Has anybody handled that situation before?

Apparently not: even in the libMesh SVN head, line 572 of configure.in
turns off PETSc unless MPI is also enabled.  Deleting lines
564,571-573 should fix that problem, but since we obviously haven't
been testing the with-petsc, without-mpi case then there are probably
bugs with it.  libMesh::COMM_WORLD is only defined with MPI enabled,
the LibMeshInit function only initializes PETSc with MPI enabled...
for that matter I see we've got a couple unencapsulated MPI_Reduce
calls left in petsc_vector.C.

I'll fix the obvious stuff now, but I don't have time to rebuild PETSc
and test for other incompatibilities.  You're welcome to be a guinea
pig and report whatever problems you come across, but it might be
simpler just to rebuild PETSc with its "download MPI" option
configured.  You can still run an MPI-built app on one processor
without inefficiency.
---
Roy