[mpich-discuss] Help with mpich2 1.3a1 on i7-920

[Pavan Balaji]

Gaetano,

MPI_IN_PLACE should only be specified at the root:

if (rank == root)
	MPI_Gather(MPI_IN_PLACE, scount, stype, rbuf, rcount, rtype, root, comm);
else
	MPI_Gather(sbuf, scount, stype, NULL, 0, MPI_DATATYPE_NULL, root, comm);

 -- Pavan

On 02/19/2010 01:10 AM, Gaetano Bellanca wrote:
> Dear Rajeev and Pavan,
> 
> thanks for your answers. I tried using MPI_IN_PLACE in MPI_GATHER in the
> position of the send buffer, but probably I didn't understand correctly
> its use. In fact, I'm still having errors.
> 
> Fatal error in MPI_Gather: Invalid buffer pointer, error stack:
> MPI_Gather(761): MPI_Gather(sbuf=MPI_IN_PLACE, scount=1, MPI_LOGICAL,
> rbuf=0x187f0b0, rcount=1, MPI_LOGICAL, root=0, comm=0x84000002) failed
> MPI_Gather(682): sendbuf cannot be MPI_IN_PLACE
> 
> However, it works using separate buffers as input and output.
> 
> Regards.
> 
> Gaetano
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-- 
Pavan Balaji
http://www.mcs.anl.gov/~balaji