Files
lerobot/examples/tutorial/rl/reward_classifier_example.py
T
Khalil Meftah 8a3d64033f Reward models refactor (#3142)
* feat(rewards): add RewardModelConfig and PreTrainedRewardModel base classes

* refactor(rewards): migrate Classifier from policies/sac/reward_model/ to rewards/classifier/

* refactor(rewards): migrate SARM from policies/sarm/ to rewards/sarm/

* refactor(rewards): add rewards/factory.py and remove reward model code from policies/factory.py

* refactor(rewards): update imports and delete old reward model locations

* test(rewards): add reward model tests and update existing test imports

* fix(rewards): restore full Classifier and SARM implementations

* test(rewards): restore missing CUDA and mixed precision classifier processor tests

* refactor(lerobot_train.py): remove rabc specific configuration and replace it with a generic samplerweight class in lerobot_train

* refactor(lerobot_train.py): add missing sampling weight script

* linter + missing files

* add testing for sampl weighter

* revert some useless changes, improve typing

* update docs

* add automatic detection of the progress path

* remove type exp

* improve comment

* fix: move rabc.py to rewards/sarm/ and update import paths

* refactor(imports): update reward model imports to new module structure

* refactor(imports): update reward model imports to reflect new module structure

* refactor(imports): conditionally import pandas based on availability

* feat(configs): add reward_model field to TrainPipelineConfig and Hub fields to RewardModelConfig

* refactor(policies): remove reward model branches from policy factory and __init__

* refactor(rewards): expand __init__ facade and fix SARMConfig __post_init__ crash

* feat(train): route reward model training through rewards/factory instead of policies/factory

* refactor(train): streamline reward model training logic

* fix(rewards): ensure FileNotFoundError is raised for missing config_file

* refactor(train): update __get_path_fields__ to include reward_model for config loading

* refactor(classifier): remove redundant input normalization in predict_reward method

* fix(train): raise ValueError for non-trainable reward models in train function

* refactor(pretrained_rm): add model card template

* refactor(tests): reward models

* refactor(sarm): update reset method and remove unused action prediction methods

* refactor(wandb): differentiate tags for reward model and policy training in cfg_to_group function

* fix(train): raise ValueError for PEFT usage in reward model training

* refactor(rewards): enhance RewardModelConfig with device handling and delta indices properties

---------

Co-authored-by: Michel Aractingi <michel.aractingi@huggingface.co>
2026-04-28 17:56:24 +02:00

67 lines
2.1 KiB
Python

import torch
from lerobot.datasets import LeRobotDataset
from lerobot.rewards import RewardClassifierConfig, make_reward_model, make_reward_pre_post_processors
def main():
# Device to use for training
device = "mps" # or "cuda", or "cpu"
# Load the dataset used for training
repo_id = "lerobot/example_hil_serl_dataset"
dataset = LeRobotDataset(repo_id)
# Configure the policy to extract features from the image frames
camera_keys = dataset.meta.camera_keys
config = RewardClassifierConfig(
num_cameras=len(camera_keys),
device=device,
# backbone model to extract features from the image frames
model_name="microsoft/resnet-18",
)
# Make reward model, preprocessor, and optimizer
reward_model = make_reward_model(config, dataset_stats=dataset.meta.stats)
optimizer = config.get_optimizer_preset().build(reward_model.parameters())
preprocessor, _ = make_reward_pre_post_processors(config, dataset_stats=dataset.meta.stats)
classifier_id = "<user>/reward_classifier_hil_serl_example"
# Instantiate a dataloader
dataloader = torch.utils.data.DataLoader(dataset, batch_size=16, shuffle=True)
# Training loop
num_epochs = 5
for epoch in range(num_epochs):
total_loss = 0
total_accuracy = 0
for batch in dataloader:
# Preprocess the batch and move it to the correct device.
batch = preprocessor(batch)
# Forward pass
loss, output_dict = reward_model.forward(batch)
# Backward pass and optimization
optimizer.zero_grad()
loss.backward()
optimizer.step()
total_loss += loss.item()
total_accuracy += output_dict["accuracy"]
avg_loss = total_loss / len(dataloader)
avg_accuracy = total_accuracy / len(dataloader)
print(f"Epoch {epoch + 1}/{num_epochs}, Loss: {avg_loss:.4f}, Accuracy: {avg_accuracy:.2f}%")
print("Training finished!")
# You can now save the trained reward model.
reward_model.push_to_hub(classifier_id)
if __name__ == "__main__":
main()