Thanks a lot. You are right I am using MPI_Iscatterv, in a domain decomposition code, but the problem is that for the domain which I have no data to send fro, the program will jump the routine. I can not redesign the whole program. Do you know what will happen to send call with zero size buffer? Can I just set the request to MPI_SUCCESS for ranks which I will send zero buffer to and have no receive call? Is there any other MPI routine that can do MPI_Scatterv on selected ranks? without creating a new communicator?
On Wed, Jul 16, 2014 at 3:42 PM, Matthieu Brucher < matthieu.bruc...@gmail.com> wrote: > If you are using Iscatterv (I guess it is that one), it handles the > pairs itself. You shouldn't bypass it because you think it is better. > You don't know how it is implemented, so just call Iscatterv for all > ranks. > > 2014-07-16 14:33 GMT+01:00 Ziv Aginsky <zivagin...@gmail.com>: > > I know the standard, but what if I can not bypass the send message. For > > example if I have MPI_Iscatter and for some ranks the send buffer has > zero > > size. At those ranks it will jump the MPI_Iscatter routine, which means I > > have some zero size send and no receive. > > > > > > > > > > On Wed, Jul 16, 2014 at 3:28 PM, Matthieu Brucher > > <matthieu.bruc...@gmail.com> wrote: > >> > >> Hi, > >> > >> The easiest would also to bypass the Isend as well! The standard is > >> clear, you need a pair of Isend/Irecv. > >> > >> Cheers, > >> > >> 2014-07-16 14:27 GMT+01:00 Ziv Aginsky <zivagin...@gmail.com>: > >> > I have a loop in which I will do some MPI_Isend. According to the MPI > >> > standard, for every send you need a recv!!!! > >> > > >> > If one or several of my MPI_Isend have zero size buffer, should I > still > >> > have > >> > the mpi_recv or I can do it without recv? I mean on the processor > which > >> > I > >> > should recv the data I know priory that my buffer is with zero size. > Can > >> > I > >> > jump from MPI_Recv. > >> > > >> > The question is because of the format of the program I am using if it > >> > knows > >> > that the receiving buffer is zero it will not call the routine which > >> > contains mpi_Recv. > >> > > >> > > >> > > >> > > >> > _______________________________________________ > >> > 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/2014/07/24781.php > >> > >> > >> > >> -- > >> Information System Engineer, Ph.D. > >> Blog: http://matt.eifelle.com > >> LinkedIn: http://www.linkedin.com/in/matthieubrucher > >> Music band: http://liliejay.com/ > >> _______________________________________________ > >> 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/2014/07/24782.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/2014/07/24783.php > > > > -- > Information System Engineer, Ph.D. > Blog: http://matt.eifelle.com > LinkedIn: http://www.linkedin.com/in/matthieubrucher > Music band: http://liliejay.com/ > _______________________________________________ > 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/2014/07/24784.php >
