Dear, Thanks for the clarification.
2015-04-14 20:57 GMT+02:00 Nathan Hjelm <hje...@lanl.gov>: > > The semantics of open shmem's fetching atomics is the same as > MPI_Get_accumulate. The old value is returned *not* the new value. This > is not an uncommon semantic for atomic operations. So, no, I don't think > oshmem will be any better than MPI RMA for this use case. > > To OP. Yes, you will have to either apply the reduction locally or > perform an MPI_Get if you are interested in the new value at the target > process on the origin process. > > -Nathan > > On Tue, Apr 14, 2015 at 02:41:27PM -0400, Andy Riebs wrote: > > Nick, > > > > You may have more luck looking into the OSHMEM layer of Open MPI; > SHMEM is > > designed for one-sided communications. > > > > BR, > > Andy > > > > On 04/14/2015 02:36 PM, Nick Papior Andersen wrote: > > > > Dear all, > > I am trying to implement some features using a one-sided > communication > > scheme. > > The problem is that I understand the different one-sided > communication > > schemes as this (basic words): > > MPI_Get) > > fetches remote window memory to a local memory space > > MPI_Get_Accumulate) > > 1. fetches remote window memory to a local memory space > > 2. sends a local memory space (different from that used in 1.) to > the > > remote window and does OP on those two quantities > > MPI_Put) > > sends local memory space to remote window memory > > MPI_Accumulate) > > sends a local memory space to the remote window and does OP on > those two > > quantities > > (surprisingly the documentation says that this only works with > windows > > within the same node, note that MPI_Get_Accumulate does not say this > > constraint) > > ?) > > Where is the function that fetches remotely and does operation in a > > local memory space? > > Do I really have to do MPI_Get to local memory, then do operation > > manually? (no it is not difficult, but... ;) ) > > I would like this to exist: > > MPI_Get_Reduce(origin,...,target,...,MPI_OP,...) > > When I just looked at the API names I thought Get_Accumulate did > this, > > but to my surprise that was not the case at all. :) > > -- > > Kind regards Nick > > > > _______________________________________________ > > users mailing list > > us...@open-mpi.org > > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users > > Link to this post: > http://www.open-mpi.org/community/lists/users/2015/04/26723.php > > > _______________________________________________ > > users mailing list > > us...@open-mpi.org > > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users > > Link to this post: > http://www.open-mpi.org/community/lists/users/2015/04/26724.php > > > _______________________________________________ > users mailing list > us...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users > Link to this post: > http://www.open-mpi.org/community/lists/users/2015/04/26726.php > -- Kind regards Nick
