message: In ex19p, MPI_Finalize() needs to be called after the destructor of
  RubberOperator; this is now achieved using the MPI_Session class.
diff: @@ -197,10 +197,8 @@ void InitialDeformation(const Vector &x, Vector &y);
  int main(int argc, char *argv[])
  {
  // 1. Initialize MPI
  - int num_procs, myid;
  - MPI_Init(&argc, &argv);
  - MPI_Comm_size(MPI_COMM_WORLD, &num_procs);
  - MPI_Comm_rank(MPI_COMM_WORLD, &myid);
  + MPI_Session mpi;
  + const int myid = mpi.WorldRank();
  // 2. Parse command-line options
  const char *mesh_file = "../data/beam-tet.mesh";
  @@ -400,8 +398,6 @@ int main(int argc, char *argv[])
  // 19. Free the used memory
  delete pmesh;
  - MPI_Finalize();
  -
  return 0;
  }
  