docs/en/reference/__init__.md

metadata

description: >-
  Learn how Ultralytics uses lazy imports with __getattr__ to speed up package
  startup and load model classes like YOLO, NAS, RTDETR, and SAM only when
  needed.
keywords: >-
  Ultralytics, YOLO, lazy import, __getattr__, NAS, RTDETR, SAM, FastSAM,
  YOLOWorld, performance, startup time, optimization

Reference for ultralytics/__init__.py

!!! success "Improvements"

This page is sourced from [https://github.com/ultralytics/ultralytics/blob/main/ultralytics/\_\_init\_\_.py](https://github.com/ultralytics/ultralytics/blob/main/ultralytics/__init__.py). Have an improvement or example to add? Open a [Pull Request](https://docs.ultralytics.com/help/contributing/) — thank you! 🙏

::: ultralytics.init.getattr

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::: ultralytics.init.dir