Restart with block vector

[starkekr]

I am having some trouble implementing a restart feature for use with block vectors. The way I see it is I have to write the files using the Visit format with something like the following:

VisItDataCollection checkpoint_file(MPI_COMM_WORLD, problem_name+"visit");
checkpoint_file.SetMesh(mesh);
for (int i = 0; i < n_ops; ++i)
    checkpoint_file.RegisterField("eta"+to_string(i), &ind_var_gf_vec[i]);
checkpoint_file.SetFormat(DataCollection::PARALLEL_FORMAT);
checkpoint_file.SetPrecision(16);
checkpoint_file.Save();

in the above ind_var_gf_vec is a vector of ParGridFunction's refering to the BlockVector that stores the solution variables.

vector<ParGridFunction> ind_var_gf_vec(n_ops);
for (int i = 0; i < n_ops; ++i) {
  ind_var_gf_vec.push_back(ParGridFunction(_spaces[i]));
  ind_var_gf_vec[i].MakeTRef(_spaces[i], xp.GetBlock(i), 0);
}

Then on restart I do something like the following:

if (is_restart) { // overwrite the mesh pointer if we are restarting
 checkpoint_file.Load(restart_cycle);
 mesh = dynamic_cast<ParMesh*>(checkpoint_file.GetMesh());
}

to load the mesh. This is where I am having trouble. Now I need to set the BlockVector with the solution from the restart file. I have tried the following but am lost:

if (is_restart==true){ // read from checkpoint file
  std::vector<GridFunction *> saved_ops(n_ops);
  for (int i = 0; i < n_ops; ++i){
	saved_ops[i] = checkpoint_file.GetParField("eta"+to_string(i));
	ind_var_gf_vec[dof_map_ac[i]].ProjectGridFunction(*saved_ops[i]);
	ind_var_gf_vec[dof_map_ac[i]].SetTrueVector();
  }
}

What is the correct way to reinitialize the BlockVector xp?