metadata
description: >-
Explore detailed implementations of loss functions for DETR and RT-DETR models
in Ultralytics.
keywords: >-
ultralytics, YOLO, DETR, RT-DETR, loss functions, object detection, deep
learning, focal loss, varifocal loss, Hungarian matcher
Reference for ultralytics/models/utils/loss.py
!!! Note
This file is available at [https://github.com/ultralytics/ultralytics/blob/main/ultralytics/models/utils/loss.py](https://github.com/ultralytics/ultralytics/blob/main/ultralytics/models/utils/loss.py). If you spot a problem please help fix it by [contributing](https://docs.ultralytics.com/help/contributing/) a [Pull Request](https://github.com/ultralytics/ultralytics/edit/main/ultralytics/models/utils/loss.py) 🛠️. Thank you 🙏!