The attached version is modified to use passive target, which does not require collective synchronization for remote access.
Note that I didn't compile and run this and don't write MPI in Fortran so there may be syntax errors. Jeff On Thu, Jan 16, 2014 at 11:03 AM, Christoph Niethammer <nietham...@hlrs.de> wrote: > 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 -- Jeff Hammond jeff.scie...@gmail.com
var_access.f95
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