--- description: Learn how to use Ultralytics YOLO's built-in callbacks `on_pretrain_routine_start` and `on_train_epoch_end` for improved training performance. keywords: Ultralytics, YOLO, callbacks, weights, biases, training --- ## _log_plots --- ### ::: ultralytics.yolo.utils.callbacks.wb._log_plots <br><br> ## on_pretrain_routine_start --- ### ::: ultralytics.yolo.utils.callbacks.wb.on_pretrain_routine_start <br><br> ## on_fit_epoch_end --- ### ::: ultralytics.yolo.utils.callbacks.wb.on_fit_epoch_end <br><br> ## on_train_epoch_end --- ### ::: ultralytics.yolo.utils.callbacks.wb.on_train_epoch_end <br><br> ## on_train_end --- ### ::: ultralytics.yolo.utils.callbacks.wb.on_train_end <br><br>