Yes, this is intentional. It’s an additional error check and is showing a bug in your user code. You can suppress this error using the environment MPIR_CVAR_COLL_ALIAS_CHECK=0, but I wouldn’t recommend it. — Pavan On Jul 6, 2014, at 6:29 AM, Lisandro Dalcin <[email protected]> wrote:

This is from a build of master updated today and configured with --enable-g=all. AFAICT, previous versions of MPICH did not generate this error. Was this an intentional change?

Traceback (most recent call last): File "/home/dalcinl/Devel/mpi4py-dev/test/test_msgzero.py", line 36, in testReductions comm.Reduce_scatter_block(self.null_b, self.null_b) File "Comm.pyx", line 714, in mpi4py.MPI.Comm.Reduce_scatter_block (src/mpi4py.MPI.c:93219) Exception: Invalid buffer pointer, error stack: PMPI_Reduce_scatter_block(1182): MPI_Reduce_scatter_block(sbuf=(nil), rbuf=(nil), recvcount=0, MPI_INT, MPI_SUM, MPI_COMM_SELF) failed PMPI_Reduce_scatter_block(1142): Buffers must not be aliased

-- Lisandro Dalcin --------------- CIMEC (UNL/CONICET) Predio CONICET-Santa Fe Colectora RN 168 Km 472, Paraje El Pozo 3000 Santa Fe, Argentina Tel: +54-342-4511594 (ext 1016) Tel/Fax: +54-342-4511169 _______________________________________________ To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/devel