[Mpi3-bwcompat] Teleconf tomorrow?

[Fab Tillier]

Quincey Koziol wrote on Thu, 14 Oct 2010 at 20:44:23

> On Oct 14, 2010, at 2:29 PM, Jeff Squyres wrote:
> 
>> On Oct 14, 2010, at 2:54 PM, Fab Tillier wrote:
>> 
>>> 2. Add just the bare minimum, leverage datatypes to work around
>>> counts.  Note that this requires introducing w versions of v
>>> collective APIs, to allow for different types (since the v functions
>>> allow different counts from each participant.)
>> 
>> This option also includes the "output" functions, right?
> 
> 	Yes, that's the basic idea.
> 
> 	BTW, I think this is a perfectly acceptable solution (as much as
> I'd like a blue pony :-).  Fab was talking about just doing this, along
> with introducing MPI_Count, etc. for _future_ routines and getting a
> consensus from the forum that all future routines would use MPI_Count,
> etc.  Since it only duplicates a few functions now (they necessary ones
> to get the I/O and datatype routines working with large counts), it
> satisfies a lot of "agile" design guidelines and I think it might be a
> very reasonable thing to do.

I don't know if the forum would go for defining new functions to use MPI_Count only.  I think it's a brilliant idea personally, though one could make the argument that requiring something like MPI_IAlltoallv to take arrays of MPI_Count when taking arrays of int would be half the size would be detrimental to performance.

-Fab