extern vector<TileBox> thread_local_tilebox;

  // get more precision for floats, could also use https://stackoverflow.com/a/30968371

  // get more precision for floats, could also use
  // https://stackoverflow.com/a/30968371

      TileBox &tilebox = thread_local_tilebox.at(omp_get_thread_num());

      TileBox tilebox;