This is the code repository for MobILE: Model-Based Imitation Learning from Observation Alone (NeurIPS 2021)

Link to pdf: https://arxiv.org/abs/2102.10769

Install openai gym by running cd gym && pip install -e .

Install mjrl by running cd mjrl && pip install -e .

Install mbil by running cd mbil && pip install -e .

Additional dependencies are listed in requirements.txt. The experiments are run using MuJoCo physics, which requires a license to install. Please follow the instructions on MuJoCo Website

mjrl is our policy gradient library that we modified to inferface with our cost functions when doing model-based policy gradient. This modification can be seen in mjrl/mjrl/algos/batch_reinforce.py. We use TRPO/NPG by default, but in principle one could replace TRPO/NPG with other algorithms/repositories.

mbil (model based imitation learning) is where we have most of the components.

1. cost: directory where cost functions go
2. dynamics_model: directory with the dynamics model ensembles
3. dataset: utility/object for creating datasets
4. env: contains the model-based wrappers. Add to wrappers.py
5. utils: modify/add to arguments.py for argparse args

This repository supports 2 modified MuJoCo environments. They are

• Hopper (Hopper-v6, deterministic)
• Walker2d (Walker2d-v4, deterministic)

If you would like to add an environment, register the environment in /mbil/mbil/gym_env/__init__.py according to OpenAI Gym instructions.

In the data directory, place the expert dataset in the data/expert_data directory. Note to modify the dataset format please see mbil/utils/util.py. Generally we only expect a tuple of state and next state from the expert demonstrations.

We provide an example run script for Hopper, example/run_hopper.sh, that can be modified to be used with any other registered environment. To view all the possible arguments you can run please see the argparse in mbil/utils/arguments.py. Note you would need to approprietly set the dataset path.

To cite this work, please use the following citation. Note that this repository builds upon MJRL so please also cite any references noted in the README here.

@article{kidambi2021mobile,
      title={MobILE: Model-Based Imitation Learning from Observations Alone},
      author={Rahul Kidambi and Jonathan D. Chang and Wen Sun},
      year={2021},
      eprint={2102.10769},
      archivePrefix={arXiv},
      primaryClass={cs.LG}
}