On Aug 1, 2017, at 5:56 AM, Diego Avesani <diego.aves...@gmail.com> wrote: > > If I do this: > > CALL MPI_SCATTER(PP, npart, MPI_DOUBLE, PPL, 10,MPI_DOUBLE, 0, MASTER_COMM, > iErr) > > I get an error. This because some CPU does not belong to MATER_COMM. The > alternative should be: > > IF(rank.LT.0)THEN > CALL MPI_SCATTER(PP, npart, MPI_DOUBLE, PPL, 10,MPI_DOUBLE, 0, > MASTER_COMM, iErr) > ENDIF
MPI_PROC_NULL is a sentinel value; I don't think you can make any assumptions about its value (i.e., that it's negative). In practice, it probably always is, but if you want to check the rank, you should compare it to MPI_PROC_NULL. That being said, comparing MASTER_COMM to MPI_COMM_NULL is no more expensive than comparing an integer. So that might be a bit more expressive to read / easier to maintain over time, and it won't cost you any performance. -- Jeff Squyres jsquy...@cisco.com _______________________________________________ users mailing list users@lists.open-mpi.org https://lists.open-mpi.org/mailman/listinfo/users
