let () =
  Printf.printf "Hello from rank %d of %d.\n" Parallel.rank Parallel.size;
  let () = Parallel.barrier () in
(*
let v = Parallel.Vec.init 47 (fun i -> float_of_int i) in
*)
  let a = Array.init 6 (fun i -> float_of_int (i+1)) |> Lacaml.D.Vec.of_array in
  let v = Parallel.Vec.of_vec a in
  Format.printf "%a" Parallel.Vec.pp v;
  let w = Parallel.Vec.to_vec v in
  if Parallel.master then
      Format.printf "@[%a@]@;" (Lacaml.Io.pp_lfvec ()) w;
  print_newline ();