On 12/02/18 12:11 PM, Jed Brown wrote:
Eric Chamberland <eric.chamberl...@giref.ulaval.ca> writes:
why does mpi stuff appears in the first one and not the second?
I would prefer to have "-lmpi" in the second one too... When is it
decided to "hide" external packages "under" PETSc? At configuration time?
I don't know what pkg-config recommends in this situation, but consider
that petscsys.h includes mpi.h so a corresponding -I flag needs to be on
the command line any time you compile code that calls PETSc. If your
application never calls MPI directly, it would be safe to link without
-lmpi.
ok, understood. We do have MPI calls (C API). I then have to add -lmpi
myself and not rely on pkg-config of PETSC for this one and it is normal...
Also note that PETSc provides symbols (like PETSC_COMM_WORLD) which also
have the effect that merely calling PETSc does not require directly
referencing MPI symbols (MPI_COMM_WORLD is a symbol, not a macro, in
Open MPI).
And that PETSc built with MPICH can be linked unmodified with other
conforming MPI implementations.
http://www.mpich.org/abi/
ok, that's interesting to know about!
I explicitly prohibited to execute with a different MPI lib/version than
the one used to compile. I could relax a bit this constraint then...
Thanks again,
Eric
