On Wed, Apr 25, 2018 at 2:36 PM, Jed Brown <[email protected]> wrote:

It is currently installed to include/petsc/mpiuni/mpi.h and petscsys.h includes it as <mpi.h>, which means that users of MPIUNI need to put -I/prefix/include/petsc/mpiuni in their command lines. Matt and I agree that this is bad. We disagree on the solution.

He wants to install it to /prefix/include/mpi.h as though the user had written --download-mpich. This would conflict if a user later installs a real MPI to that location.

The idea should be that "installing" means that everyone is using compatible things from that location. If you allow an MPIUNI PETSc to be installed to a location that also has another MPI, what does mpiexec in ./bin do? There is just as much potential for confusion as there is when putting an MPICH PETSc in a location with OpenMPI installed. Matt

I would rather that petscsys.h include <petsc/mpiuni/mpi.h> because it can't be used without PETSc and nobody who ever wrote #include <mpi.h> in their own code will be happy if they get MPIUNI.

-- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/~mk51/>