Dear George, Dear all, thanks, thanks a lot. I will tell you everything. I will try also to implement your suggestion.
Unfortunately, the program that I have show to you is not working. I get the following error: [] *** An error occurred in MPI_Comm_rank [] *** reported by process [643497985,7] [] *** on communicator MPI_COMM_WORLD [] *** MPI_ERR_COMM: invalid communicator [] *** MPI_ERRORS_ARE_FATAL (processes in this communicator will now abort, [] *** and potentially your MPI job) [warn] Epoll ADD(4) on fd 47 failed. Old events were 0; read change was 0 (none); write change was 1 (add): Bad file descriptor [warn] Epoll ADD(4) on fd 65 failed. Old events were 0; read change was 0 (none); write change was 1 (add): Bad file descriptor [] 8 more processes have sent help message help-mpi-errors.txt / mpi_errors_are_fatal [] Set MCA parameter "orte_base_help_aggregate" to 0 to see all help / error messages What do you think could be the error? Really, Really thanks again Diego On 27 July 2017 at 15:57, George Bosilca <bosi...@icl.utk.edu> wrote: > This looks good. If performance is critical you can speed up the entire > process by using MPI_Comm_create_group instead of the second > MPI_COMM_SPLIT. The MPI_Comm_create_group is collective only over the > resulting communicator and not over the source communicator, so its cost is > only dependent of the number of groups and not on the total number of > processes. > > You can also try to replace the first MPI_COMM_SPLIT by the same approach. > I would be curious to see the outcome. > > George. > > > On Thu, Jul 27, 2017 at 9:44 AM, Diego Avesani <diego.aves...@gmail.com> > wrote: > >> Dear George, Dear all, >> >> I have tried to create a simple example. In particular, I would like to >> use 16 CPUs and to create four groups according to rank is and then a >> communicator between masters of each group.I have tried to follow the first >> part of this example >> <http://mpitutorial.com/tutorials/introduction-to-groups-and-communicators/>. >> In the last part I have tried to create a communicator be masters as >> suggested by George. >> >> Here my example: >> >> CALL MPI_INIT(ierror) >> CALL MPI_COMM_SIZE(MPI_COMM_WORLD, nCPU, ierror) >> CALL MPI_COMM_RANK(MPI_COMM_WORLD, rank, ierror) >> ! >> colorloc = rank/4 >> ! >> CALL MPI_COMM_SPLIT(MPI_COMM_WORLD,colorloc,rank,*NEW_COMM*,ierror) >> CALL MPI_COMM_RANK(*NEW_COMM*, subrank,ierror); >> CALL MPI_COMM_SIZE(*NEW_COMM*, subnCPU,ierror); >> ! >> IF(MOD(rank,4).EQ.0)THEN >> *! where I set color for the masters* >> colorglobal = MOD(rank,4) >> ELSE >> colorglobal = MPI_UNDEFINED >> ENDIF >> ! >> CALL MPI_COMM_SPLIT(MPI_COMM_WORLD,colorglobal,rank,LEADER_COMM,ierror) >> CALL MPI_COMM_RANK(*LEADER_COMM*, leader_rank,ierror); >> CALL MPI_FINALIZE(ierror) >> >> I would like to know if this could be correct. I mean if I have >> understood correctly what George told me about the code design. Now, this >> example does not work, but probably there is some coding error. >> >> Really, Really thanks >> Diego >> >> >> >> >> >> >> >> Diego >> >> >> On 27 July 2017 at 10:42, Diego Avesani <diego.aves...@gmail.com> wrote: >> >>> Dear George, Dear all, >>> >>> A question regarding program design: >>> The draft that I have sent to you has to be done many and many times. >>> Does the splitting procedure ensure efficiency? >>> >>> I will try, at a lest to create groups and split them. I am a beginner >>> in the MPI groups environment. >>> really, really thanks. >>> >>> You are my lifesaver. >>> >>> >>> >>> Diego >>> >>> >>> On 26 July 2017 at 15:09, George Bosilca <bosi...@icl.utk.edu> wrote: >>> >>>> Diego, >>>> >>>> As all your processes are started under the umbrella of a single >>>> mpirun, they have a communicator in common, the MPI_COMM_WORLD. >>>> >>>> One possible implementation, using MPI_Comm_split, will be the >>>> following: >>>> >>>> MPI_Comm small_comm, leader_comm; >>>> >>>> /* Create small_comm on all processes */ >>>> >>>> /* Now use MPI_Comm_split on MPI_COMM_WORLD to select the leaders */ >>>> MPI_Comm_split( MPI_COMM_WORLD, >>>> i_am_leader(small_comm) ? 1 : >>>> MPI_UNDEFINED, >>>> rank_in_comm_world, >>>> &leader_Comm); >>>> >>>> The leader_comm will be a valid communicator on all leaders processes, >>>> and MPI_COMM_NULL on all others. >>>> >>>> George. >>>> >>>> >>>> >>>> On Wed, Jul 26, 2017 at 4:29 AM, Diego Avesani <diego.aves...@gmail.com >>>> > wrote: >>>> >>>>> Dear George, Dear all, >>>>> >>>>> I use "mpirun -np xx ./a.out" >>>>> >>>>> I do not know if I have some common grounds. I mean, I have to >>>>> design everything from the begging. You can find what I would like to do >>>>> in >>>>> the attachment. Basically, an MPI cast in another MPI. Consequently, I am >>>>> thinking to MPI groups or MPI virtual topology with a 2D cart, using the >>>>> columns as "groups" and the first rows as the external groups to handle >>>>> the >>>>> columns. >>>>> >>>>> What do think? What do you suggest? >>>>> Really Really thanks >>>>> >>>>> >>>>> Diego >>>>> >>>>> >>>>> On 25 July 2017 at 19:26, George Bosilca <bosi...@icl.utk.edu> wrote: >>>>> >>>>>> Diego, >>>>>> >>>>>> Assuming you have some common grounds between the 4 initial groups >>>>>> (otherwise you will have to connect them via >>>>>> MPI_Comm_connect/MPI_Comm_accept) >>>>>> you can merge the 4 groups together and then use any MPI mechanism to >>>>>> create a partial group of leaders (such as MPI_Comm_split). >>>>>> >>>>>> If you spawn the groups via MPI_Comm_spawn then the answer is >>>>>> slightly more complicated, you need to use MPI_Intercomm_create, with the >>>>>> spawner as the bridge between the different communicators (and then >>>>>> MPI_Intercomm_merge to create your intracomm). You can find a good answer >>>>>> on stackoverflow on this at https://stackoverflow.com/ques >>>>>> tions/24806782/mpi-merge-multiple-intercoms-into-a-single-intracomm >>>>>> >>>>>> How is your MPI environment started (single mpirun or mpi_comm_spawn) >>>>>> ? >>>>>> >>>>>> George. >>>>>> >>>>>> >>>>>> >>>>>> On Tue, Jul 25, 2017 at 10:44 AM, Diego Avesani < >>>>>> diego.aves...@gmail.com> wrote: >>>>>> >>>>>>> Dear All, >>>>>>> >>>>>>> I am studying Groups and Communicators, but before start going in >>>>>>> detail, I have a question about groups. >>>>>>> >>>>>>> I would like to know if is it possible to create a group of masters >>>>>>> of the other groups and then a intra-communication in the new group. I >>>>>>> have >>>>>>> spent sometime reading different tutorial and presentation, but it is >>>>>>> difficult, at least for me, to understand if is it possible to create >>>>>>> this >>>>>>> sort of MPI cast in another MPI. >>>>>>> >>>>>>> In the attachment you can find a pictures that summarize what I >>>>>>> would like to do. >>>>>>> >>>>>>> Another strategies could be use virtual topology. >>>>>>> >>>>>>> What do you think? >>>>>>> >>>>>>> I really, really, appreciate any kind of help, suggestions or link >>>>>>> where I can study this topics. >>>>>>> >>>>>>> Again, thanks >>>>>>> >>>>>>> Best Regards, >>>>>>> >>>>>>> Diego >>>>>>> >>>>>>> _______________________________________________ >>>>>>> users mailing list >>>>>>> users@lists.open-mpi.org >>>>>>> https://rfd.newmexicoconsortium.org/mailman/listinfo/users >>>>>>> >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> users mailing list >>>>>> users@lists.open-mpi.org >>>>>> https://rfd.newmexicoconsortium.org/mailman/listinfo/users >>>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> users mailing list >>>>> users@lists.open-mpi.org >>>>> https://rfd.newmexicoconsortium.org/mailman/listinfo/users >>>>> >>>> >>>> >>>> _______________________________________________ >>>> users mailing list >>>> users@lists.open-mpi.org >>>> https://rfd.newmexicoconsortium.org/mailman/listinfo/users >>>> >>> >>> >> >> _______________________________________________ >> users mailing list >> users@lists.open-mpi.org >> https://rfd.newmexicoconsortium.org/mailman/listinfo/users >> > > > _______________________________________________ > users mailing list > users@lists.open-mpi.org > https://rfd.newmexicoconsortium.org/mailman/listinfo/users >
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