Method GetField

IO/IOSS/vtkIOSSReaderInternal.cxx:1954–2071

}

vtkSmartPointer<vtkAbstractArray> vtkIOSSReaderInternal::GetField(const std::string& fieldname,
  Ioss::Region* region, const Ioss::GroupingEntity* group_entity, const DatabaseHandle& handle,
  int timestep, vtkIdTypeArray* ids_to_extract, const std::string& cache_key_suffix)
{
  const auto get_field = [&fieldname, &region, &timestep, &handle, this](
                           const Ioss::GroupingEntity* entity) -> vtkSmartPointer<vtkAbstractArray>
  {
    if (!entity->field_exists(fieldname))
    {
      return nullptr;
    }

    if (!vtkIOSSUtilities::IsFieldTransient(entity, fieldname))
    {
      // non-time dependent field.
      return vtkIOSSUtilities::GetData(entity, fieldname, /*transform=*/nullptr, &this->Cache);
    }

    // determine state for transient data.
    const auto& stateVector = this->DatabaseTimes[handle.first];
    if (stateVector.empty())
    {
      // see paraview/paraview#20658 for why this is needed.
      return nullptr;
    }

    auto iter = std::find_if(stateVector.begin(), stateVector.end(),
      [&](const std::pair<int, double>& pair)
      { return pair.second == this->TimestepValues[timestep]; });

    if (iter == stateVector.end())
    {
      throw std::runtime_error("Invalid timestep chosen: " + vtk::to_string(timestep));
    }
    const int state = iter->first;
    region->begin_state(state);
    try
    {
      const std::string key = "__vtk_transient_" + fieldname + "_" + vtk::to_string(state) + "__";
      auto f =
        vtkIOSSUtilities::GetData(entity, fieldname, /*transform=*/nullptr, &this->Cache, key);
      region->end_state(state);
      return f;
    }
    catch (...)
    {
      region->end_state(state);
      std::rethrow_exception(std::current_exception());
    }
  };

  const auto get_field_for_entity = [&]()
  {
    if (group_entity->type() == Ioss::EntityType::SIDESET)
    {
      // sidesets need to be handled specially. For sidesets, the fields are
      // available on nested sideblocks.
      std::vector<vtkSmartPointer<vtkAbstractArray>> arrays;