On 9/16/2010 9:58 AM, David Zhang wrote:
It's compiler specific I think. I've done this with OpenMPI no
problem, however on one another cluster with ifort I've gotten error
messages about not using MPI_IN_PLACE. So I think if it compiles, it
should work fine.
On Thu, Sep 16, 2010 at 10:01 AM, Tom Rosmond <rosm...@reachone.com
<mailto:rosm...@reachone.com>> wrote:
I am working with a Fortran 90 code with many MPI calls like this:
call mpi_gatherv(x,nsize(rank+1),
mpi_real,x,nsize,nstep,mpi_real,root,mpi_comm_world,mstat)
Compiler can't affect what happens here (unless maybe you use x again
somewhere). Maybe you mean MPI library? Intel MPI probably checks this
at run time and issues an error.
I've dealt with run-time errors (which surfaced along with an ifort
upgrade) which caused silent failure (incorrect numerics) on openmpi but
a fatal diagnostic from Intel MPI run-time, due to multiple uses of the
same buffer. Moral: even if it works for you now with openmpi, you
could be setting up for unexpected failure in the future.
--
Tim Prince
