chore(docs): update doctrines pipeline files (#1872)

* docs(processor): update docstrings batch_processor

* docs(processor): update docstrings device_processor

* docs(processor): update docstrings tokenizer_processor

* update docstrings processor_act

* update docstrings for pipeline_features

* update docstrings for utils

* update docstring for processor_diffusion

* update docstrings factory

* add docstrings to pi0 processor

* add docstring to pi0fast processor

* add docstring classifier processor

* add docstring to sac processor

* add docstring smolvla processor

* add docstring to tdmpc processor

* add docstring to vqbet processor

* add docstrings to converters

* add docstrings for delta_action_processor

* add docstring to gym action processor

* update hil processor

* add docstring to joint obs processor

* add docstring to migrate_normalize_processor

* update docstrings normalize processor

* update docstring normalize processor

* update docstrings observation processor

* update docstrings rename_processor

* add docstrings robot_kinematic_processor

* cleanup rl comments

* add docstring to train.py

* add docstring to teleoperate.py

* add docstrings to phone_processor.py

* add docstrings to teleop_phone.py

* add docstrings to control_utils.py

* add docstrings to visualization_utils.py

---------

Co-authored-by: Pepijn <pepijn@huggingface.co>

src/lerobot/scripts/train.py

@@ -65,6 +65,28 @@ def update_policy(
     use_amp: bool = False,
     lock=None,
 ) -> tuple[MetricsTracker, dict]:
+    """
+    Performs a single training step to update the policy's weights.
+
+    This function executes the forward and backward passes, clips gradients, and steps the optimizer and
+    learning rate scheduler. It also handles mixed-precision training via a GradScaler.
+
+    Args:
+        train_metrics: A MetricsTracker instance to record training statistics.
+        policy: The policy model to be trained.
+        batch: A batch of training data.
+        optimizer: The optimizer used to update the policy's parameters.
+        grad_clip_norm: The maximum norm for gradient clipping.
+        grad_scaler: The GradScaler for automatic mixed-precision training.
+        lr_scheduler: An optional learning rate scheduler.
+        use_amp: A boolean indicating whether to use automatic mixed precision.
+        lock: An optional lock for thread-safe optimizer updates.
+
+    Returns:
+        A tuple containing:
+        - The updated MetricsTracker with new statistics for this step.
+        - A dictionary of outputs from the policy's forward pass, for logging purposes.
+    """
     start_time = time.perf_counter()
     device = get_device_from_parameters(policy)
     policy.train()
@@ -108,6 +130,20 @@ def update_policy(
 
 @parser.wrap()
 def train(cfg: TrainPipelineConfig):
+    """
+    Main function to train a policy.
+
+    This function orchestrates the entire training pipeline, including:
+    - Setting up logging, seeding, and device configuration.
+    - Creating the dataset, evaluation environment (if applicable), policy, and optimizer.
+    - Handling resumption from a checkpoint.
+    - Running the main training loop, which involves fetching data batches and calling `update_policy`.
+    - Periodically logging metrics, saving model checkpoints, and evaluating the policy.
+    - Pushing the final trained model to the Hugging Face Hub if configured.
+
+    Args:
+        cfg: A `TrainPipelineConfig` object containing all training configurations.
+    """
     cfg.validate()
     logging.info(pformat(cfg.to_dict()))