Method initialize

src/ifcgeom/Iterator.cpp:18–168

* Initialize iterator's list of tasks. * * Will automatically process first element, if 'defer-processing-first-element' is not set to `true`. * * @return Returns true if the iterator is initialized with any elements, false otherwise. * * @note * - A true return value does not guarantee successful initialization of all elements. * Some elements may have failed to initialize. Check had_error_proc

*   element fails, even if subsequent elements could be initialized successfully.
*/
bool IfcGeom::Iterator::initialize() {
	using std::chrono::high_resolution_clock;

	if (initialization_outcome_) {
		return *initialization_outcome_;
	}

	time_points[0] = high_resolution_clock::now();
	std::vector<ifcopenshell::geometry::geometry_conversion_task> reps;
	if (num_threads_ != 1) {
		// @todo this shouldn't be necessary with properly immutable taxonomy items
		converter_->mapping()->use_caching() = false;
	}
	try {
		converter_->mapping()->get_representations(reps, filters_);
	} catch (const std::exception& e) {
		Logger::Error(e);
	}
	time_points[1] = high_resolution_clock::now();

	for (auto& task : reps) {
		geometry_conversion_result res;
		res.index = task.index;
		if (!settings_.get<ifcopenshell::geometry::settings::NoParallelMapping>().get()) {
			res.representation = task.representation;
			res.products_2 = task.products;
		} else {
			res.item = converter_->mapping()->map(task.representation);
			if (!res.item) {
				continue;
			}
			std::transform(task.products->begin(), task.products->end(), std::back_inserter(res.products), [this, &res](IfcUtil::IfcBaseClass* prod) {
				auto prod_item = converter_->mapping()->map(prod);
				return std::make_pair(prod->as<IfcUtil::IfcBaseEntity>(), ifcopenshell::geometry::taxonomy::cast<ifcopenshell::geometry::taxonomy::geom_item>(prod_item)->matrix);
			});
		}
		tasks_.push_back(res);
	}

	if (settings_.get<ifcopenshell::geometry::settings::NoParallelMapping>().get() && settings_.get<ifcopenshell::geometry::settings::PermissiveShapeReuse>().get()) {
		std::unordered_map<
			ifcopenshell::geometry::taxonomy::item::ptr,
			std::vector<std::pair<IfcUtil::IfcBaseEntity*, ifcopenshell::geometry::taxonomy::matrix4::ptr>>> folded;

		for (auto& r : tasks_) {
			auto i = r.item;

			Eigen::Matrix4d m4 = Eigen::Matrix4d::Identity();

			while (auto col = std::dynamic_pointer_cast<ifcopenshell::geometry::taxonomy::collection>(i)) {
				if (col->children.size() == 1) {
					if (col->matrix) {
						m4 *= col->matrix->ccomponents();
					}
					i = col->children[0];
				} else {
					break;
				}