message: Address comment for empty attributes/bdr_attributes
diff: @@ -25,7 +25,8 @@ void LinearFormExtension::Assemble()
  "match the number of vector dofs!");
  const Array<Array<int>*> &domain_integs_marker = *lf->GetDLFI_Marker();
  - const int mesh_attributes_max = fes.GetMesh()->attributes.Max();
  + const int mesh_attributes_max = fes.GetMesh()->attributes.Size() ?
  + fes.GetMesh()->attributes.Max() : 0;
  const Array<LinearFormIntegrator*> &domain_integs = *lf->GetDLFI();
  for (int k = 0; k < domain_integs.Size(); ++k)
  @@ -64,7 +65,8 @@ void LinearFormExtension::Assemble()
  }
  const Array<Array<int>*> &boundary_integs_marker = lf->boundary_integs_marker;
  - const int bdr_attributes_max = fes.GetMesh()->bdr_attributes.Max();
  + const int bdr_attributes_max = fes.GetMesh()->bdr_attributes.Size() ?
  + fes.GetMesh()->bdr_attributes.Max() : 0;
  const Array<LinearFormIntegrator*> &boundary_integs = lf->boundary_integs;
  for (int k = 0; k < boundary_integs.Size(); ++k)
  