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From: Robert Latham (robl_at_[hidden])
Date: 2006-03-14 12:05:51


I've got a bit of an odd bug here. I've been playing around with MPI
process management routines and I notied the following behavior with

Two processes (a and b), linked with ompi, but started independently
(no mpiexec, just started the programs directly).

- a and b: call MPI_Init
- a: open a unix network socket on 'fd'
- b: connect to a's socket
- a and b: call MPI_Comm_join over 'fd'
- a and b: call MPI_Intercomm_merge, get intracommunicator.

These steps all work fine.

Now the odd part: a and b call MPI_Comm_rank and MPI_Comm_size over
the intracommunicator. Both (correctly) think Comm_size is two, but
both also think (incorrectly) that they are rank 1.


Rob Latham
Mathematics and Computer Science Division    A215 0178 EA2D B059 8CDF
Argonne National Labs, IL USA                B29D F333 664A 4280 315B