$ ! The following is put on hold because it looks like a crazy idea
$ ! now creating separate exclusive communicator for the master nodes only $ ! the name of the new communicator is MPI_COMM_ROOTS $ ! if we want quickly broadcast something, then we can use two BCAST calls $ color = 1 $ if (iammaster) color = 0 $ call MPI_COMM_SPLIT(MPI_COMM_WORLD,color,myid_world,MPI_COMM_ROOTS,mpi_err)