Loadable Function: [RANK INFO] = MPI_Comm_rank (COMM)

Return the rank of the calling process in the specified communicator. If the comunicator object COMM (loaded with MPI_Comm_Load) is omitted an error is thrown.

             RANK rank of the calling process in group of communicator
             INFO (int) return code
                0 MPI_SUCCESS    No error
                5 MPI_ERR_COMM   Invalid communicator (NULL?)
               13 MPI_ERR_ARG    Invalid argument (typically a NULL pointer?)
          SEE ALSO: MPI_Comm_size