On Mon, Apr 25, 2011 at 22:46, Roy Stogner <roystgnr@ices.utexas.edu> wrote:
And there's one place that's more worrisome:
what's the next step up from MPI_LONG_DOUBLE?  There's standard MPI
Real*16 support for Fortran; would that work for 16 byte C/C++ FP too?

I don't know if that works. The latest MPICH2 defines the type, but Open MPI does not.

You can always use MPIU_SCALAR (and MPIU_SUM, MPIU_MAX, etc) with PETSc.