[Mpi-22] mpi-22 Digest, Vol 2, Issue 7

[Jeff Squyres]

On May 5, 2008, at 1:28 PM, Supalov, Alexander wrote:

> Thank you. We can actually introduce what you propose, possibly with  
> a query function to make it still easier to live with, as early as  
> in MPI 2.2, as a subset precursor. Judging by the discussion in  
> Chicago, subsets may not need much more than that in the end,  
> possibly with a little more flags and semantics added in MPI-3.
>
> The reservation against 32- (or for that matter, 64-) bit limitation  
> is the only one I have at the moment. Not being able to attach  
> assertions to communicators, etc. may be missed by some advanced  
> programmers, but here we need to be pragmatic: who will ever want to  
> go that deep?

Libraries that build on top of MPI may want to.  This was one of the  
prime motivations for communications, right?  (private/safe  
communications)  As Quincy stated in Chicago and on the mailing list  
(IIRC), what if a top-level app sets an assertion that a library using  
MPI can't live with?  Being able to set them per-communicator might  
alleviate that issue.


-- 
Jeff Squyres
Cisco Systems