[Mpi3-rma] MPI_Fetch_and_op and predefined datatypes

[Jeff Hammond]

If someone wants MPI_NO_OP or MPI_REPLACE on MPI_WCHAR, can't they
just do it with MPI_Get_accumulate on the appropriate width using
MPI_BYTE and MPI_SIZEOF?

I see no performance-critical justification for MPI_WCHAR atomic reads
and writes.

Jeff

On Fri, Oct 26, 2012 at 4:07 PM, Torsten Hoefler <htor at illinois.edu> wrote:
> On Fri, Oct 26, 2012 at 04:22:02PM -0500, Jeff Hammond wrote:
>> I don't want to wait for 3.1.  Are we seriously going to require
>> MPI_WCHAR support in F&Op to be MPI-3 compliant?  That makes no sense.
> I think the intent of "Any of the predefined operations for MPI_REDUCE,
> as well as MPI_NO_OP or MPI_REPLACE, can be specified as op;
> user-defined functions cannot be used." is clear. One could even dream
> up a use-case for MPI_WCHAR if one wants to emulate an atomic read
> (using MPI_NO_OP).
>
> I will not vote against an errata if you want to propose text and
> initiate the process.
>
> Best,
>   Torsten
>
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-- 
Jeff Hammond
Argonne Leadership Computing Facility
University of Chicago Computation Institute
jhammond at alcf.anl.gov / (630) 252-5381
http://www.linkedin.com/in/jeffhammond
https://wiki.alcf.anl.gov/parts/index.php/User:Jhammond