Then it sounds like we have bigger problems, like the MPIR proctable is inadequate to represent this configuration. Jeffrey Squyres wrote:

On Apr 24, 2012, at 3:46 PM, John DelSignore wrote:

...

I'm not familiar with any implementations where there are multiple MPI processes per OS process. I did read Snir's proposal, but I can't say that I'm less confused about what it implies relative to an MPI process's rank in MPI_COMM_WORLD. Are you saying that a single OS process may have contain multiple MPI processes where each MPI process has a unique rank in MPI_COMM_WORLD? And therefore, if we try to use the environment to identify an OS process's rank in MPI_COMM_WORLD, it would have to be more like a list of ranks rather than a single value?

Yes.

And I believe IBM wants to make a comeback with this model (threads that have different MPI_COMM_WORLD rank values, for example).