Isn't it because you're calling MPI_Scatter() even on rank 2 which is not part of your new_comm?
Regards, Nadia users-boun...@open-mpi.org wrote on 03/06/2012 01:52:06 PM: > De : Timothy Stitt <timothy.stit...@nd.edu> > A : "us...@open-mpi.org" <us...@open-mpi.org> > Date : 03/06/2012 01:52 PM > Objet : [OMPI users] Scatter+Group Communicator Issue > Envoyé par : users-boun...@open-mpi.org > > Hi all, > > I am scratching my head over what I think should be a relatively > simple group communicator operation. I am hoping some kind person > can put me out of my misery and figure out what I'm doing wrong. > > Basically, I am trying to scatter a set of values to a subset of > process ranks (hence the need for a group communicator). When I run > the sample code over 4 processes (and scattering to 3 processes), I > am getting a group-communicator related error in the scatter operation: > > > [stats.crc.nd.edu:29285] *** An error occurred in MPI_Scatter > > [stats.crc.nd.edu:29285] *** on communicator MPI_COMM_WORLD > > [stats.crc.nd.edu:29285] *** MPI_ERR_COMM: invalid communicator > > [stats.crc.nd.edu:29285] *** MPI_ERRORS_ARE_FATAL (your MPI job > will now abort) > > Complete - Rank 1 > > Complete - Rank 0 > > Complete - Rank 3 > > The actual test code is below: > > program scatter_bug > > use mpi > > implicit none > > integer :: ierr,my_rank,procValues(3),procRanks(3) > integer :: in_cnt,orig_group,new_group,new_comm,out > > call MPI_INIT(ierr) > call MPI_COMM_RANK(MPI_COMM_WORLD,my_rank,ierr) > > procRanks=(/0,1,3/) > procValues=(/0,434,268/) > in_cnt=3 > > ! Create sub-communicator > call MPI_COMM_GROUP(MPI_COMM_WORLD, orig_group, ierr) > call MPI_Group_incl(orig_group, in_cnt, procRanks, new_group, ierr) > call MPI_COMM_CREATE(MPI_COMM_WORLD, new_group, new_comm, ierr) > > call MPI_SCATTER(procValues, 1, MPI_INTEGER, out, 1, MPI_INTEGER, > 0, new_comm, ierr); > > print *,"Complete - Rank", my_rank > > end program scatter_bug > > Thanks in advance for any advice you can give. > > Regards. > > Tim. > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
