[petsc-dev] ugly shit

[Jed Brown]

On Thu, Nov 10, 2011 at 16:05, Barry Smith <bsmith at mcs.anl.gov> wrote:

>   You could have ./configure check for MPI_IN_PLACE and generate an error
> if it doesn't exist.  But do we want to say PETSc requires MPI 2.0 (or at
> least parts of it)????  Since we already have support for not having
> MPI_IN_PLACE I'd only like to remove that extra support if we knew that all
> (sane) users had access to MPI_IN_PLACE. Do we know this?
>

If we found an implementation that doesn't have it, we could define the
MPI_IN_PLACE value and have our own wrapper that did the right thing
(allocated the work array).


>
>
> > In general, can we rely on any MPI-2.0 features that have been
> implemented in mpiuni and remove the macro checking?
>
>     I don't have a clue what parts of MPI-2.0 that MPIUni does or does not
> support :-(.  I'm afraid we'll need to find out one operation at a time. It
> definitely doesn't have the one-sided stuff, can/should that be added? I
> don't see a big upside in putting the one-sided stuff into MPI uni.
>

MPI one-sided is normally used to talk to remote processes, much like
MPI_Send, which we currently define to produce an error if called. I think
it would make sense to do the same thing with the one-sided stuff.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20111110/3e99e31c/attachment.html>