Thanks a ton Christoph. That helps a lot.
2014/1/17 Christoph Niethammer <nietham...@hlrs.de> > Hello, > > Find attached a minimal example - hopefully doing what you intended. > > Regards > Christoph > > -- > > Christoph Niethammer > High Performance Computing Center Stuttgart (HLRS) > Nobelstrasse 19 > 70569 Stuttgart > > Tel: ++49(0)711-685-87203 > email: nietham...@hlrs.de > http://www.hlrs.de/people/niethammer > > > > ----- Ursprüngliche Mail ----- > Von: "Pradeep Jha" <prad...@ccs.engg.nagoya-u.ac.jp> > An: "Open MPI Users" <us...@open-mpi.org> > Gesendet: Freitag, 10. Januar 2014 10:23:40 > Betreff: Re: [OMPI users] Calling a variable from another processor > > > > Thanks for your responses. I am still not able to figure it out. I will > further simply my problem statement. Can someone please help me with a > fortran90 code for that. > > > 1) I have N processors each with an array A of size S > 2) On any random processor (say rank X), I calculate the two integer > values, Y and Z. (0<=Y<N and 0<Z<=S) > 3) On processor X, I want to get the value of A(Z) on processor Y. > > > This operation will happen parallely on each processor. Can anyone please > help me with this? > > > > > > > > 2014/1/9 Jeff Hammond < jeff.scie...@gmail.com > > > > One sided is quite simple to understand. It is like file io. You > read/write (get/put) to a memory object. If you want to make it hard to > screw up, use passive target bss wrap you calls in lock/unlock so every > operation is globally visible where it's called. > > I've never deadlocked RMA while p2p is easy to hang for nontrivial > patterns unless you only do nonblocking plus waitall. > > If one finds MPI too hard to learn, there are both GA/ARMCI and OpenSHMEM > implementations over MPI-3 already (I wrote both...). > > The bigger issue is that OpenMPI doesn't support MPI-3 RMA, just the MPI-2 > RMA stuff, and even then, datatypes are broken with RMA. Both ARMCI-MPI3 > and OSHMPI (OpenSHMEM over MPI-3) require a late-model MPICH-derivative to > work, but these are readily available on every platform normal people use > (BGQ is the only system missing, and that will be resolved soon). I've run > MPI-3 on my Mac (MPICH), clusters (MVAPICH), Cray (CrayMPI), and SGI > (MPICH). > > Best, > > Jeff > > Sent from my iPhone > > > > > On Jan 9, 2014, at 5:39 AM, "Jeff Squyres (jsquyres)" < > jsquy...@cisco.com > wrote: > > > > MPI one-sided stuff is actually pretty complicated; I wouldn't suggest > it for a beginner (I don't even recommend it for many MPI experts ;-) ). > > > > Why not look at the MPI_SOURCE in the status that you got back from the > MPI_RECV? In fortran, it would look something like (typed off the top of my > head; forgive typos): > > > > ----- > > integer, dimension(MPI_STATUS_SIZE) :: status > > ... > > call MPI_Recv(buffer, ..., status, ierr) > > ----- > > > > The rank of the sender will be in status(MPI_SOURCE). > > > > > >> On Jan 9, 2014, at 6:29 AM, Christoph Niethammer < nietham...@hlrs.de> > >> wrote: > >> > >> Hello, > >> > >> I suggest you have a look onto the MPI one-sided functionality (Section > 11 of the MPI Spec 3.0). > >> Create a window to allow the other processes to access the arrays A > directly via MPI_Get/MPI_Put. > >> Be aware of synchronization which you have to implement via > MPI_Win_fence or manual locking. > >> > >> Regards > >> Christoph > >> > >> -- > >> > >> Christoph Niethammer > >> High Performance Computing Center Stuttgart (HLRS) > >> Nobelstrasse 19 > >> 70569 Stuttgart > >> > >> Tel: ++49(0)711-685-87203 > >> email: nietham...@hlrs.de > >> http://www.hlrs.de/people/niethammer > >> > >> > >> > >> ----- Ursprüngliche Mail ----- > >> Von: "Pradeep Jha" < prad...@ccs.engg.nagoya-u.ac.jp > > >> An: "Open MPI Users" < us...@open-mpi.org > > >> Gesendet: Donnerstag, 9. Januar 2014 12:10:51 > >> Betreff: [OMPI users] Calling a variable from another processor > >> > >> > >> > >> > >> > >> I am writing a parallel program in Fortran77. I have the following > problem: 1) I have N number of processors. > >> 2) Each processor contains an array A of size S. > >> 3) Using some function, on every processor (say rank X), I calculate > the value of two integers Y and Z, where Z<S. (the values of Y and Z are > different on every processor) > >> 4) I want to get the value of A(Z) on processor Y to processor X. > >> > >> I thought of first sending the numerical value X to processor Y from > processor X and then sending A(Z) from processor Y to processor X. But it > is not possible as processor Y does not know the numerical value X and so > it won't know from which processor to receive the numerical value X from. > >> > >> I tried but I haven't been able to come up with any code which can > implement this action. So I am not posting any codes. > >> > >> Any suggestions? > >> > >> _______________________________________________ > >> users mailing list > >> us...@open-mpi.org > >> http://www.open-mpi.org/mailman/listinfo.cgi/users > >> _______________________________________________ > >> users mailing list > >> us...@open-mpi.org > >> http://www.open-mpi.org/mailman/listinfo.cgi/users > > > > > > -- > > Jeff Squyres > > jsquy...@cisco.com > > For corporate legal information go to: > http://www.cisco.com/web/about/doing_business/legal/cri/ > > > > _______________________________________________ > > users mailing list > > us...@open-mpi.org > > http://www.open-mpi.org/mailman/listinfo.cgi/users > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users >
