Transformers are Sample Efficient World Models (IRIS)

Transformers are Sample Efficient World Models
Vincent Micheli*, Eloi Alonso*, François Fleuret
* Denotes equal contribution

IRIS agent after 100k environment steps, i.e. two hours of real-time experience

IRIS playing on Asterix, Boxing, Breakout, Demon Attack, Freeway, Gopher, Kung Fu Master, Pong

tl;dr

IRIS is a data-efficient agent trained over millions of imagined trajectories in a world model.
The world model is composed of a discrete autoencoder and an autoregressive Transformer.
Our approach casts dynamics learning as a sequence modeling problem, where the autoencoder builds a language of image tokens and the Transformer composes that language over time.

BibTeX

If you find this code or paper useful, please use the following reference:

@article{iris2022,
  title={Transformers are Sample Efficient World Models},
  author={Micheli, Vincent and Alonso, Eloi and Fleuret, François},
  journal={arXiv preprint arXiv:2209.00588},
  year={2022}
}

Setup

Install PyTorch (torch and torchvision). Code developed with torch==1.11.0 and torchvision==0.12.0.
Install other dependencies: pip install -r requirements.txt
Warning: Atari ROMs will be downloaded with the dependencies, which means that you acknowledge that you have the license to use them.

Launch a training run

python src/main.py env.train.id=BreakoutNoFrameskip-v4 common.device=cuda:0 wandb.mode=online

By default, the logs are synced to weights & biases, set wandb.mode=disabled to turn it off.

Configuration

All configuration files are located in config/, the main configuration file is config/trainer.yaml.
The simplest way to customize the configuration is to edit these files directly.
Please refer to Hydra for more details regarding configuration management.

Run folder

Each new run is located at outputs/YYYY-MM-DD/hh-mm-ss/. This folder is structured as:

outputs/YYYY-MM-DD/hh-mm-ss/
│
└─── checkpoints
│   │   last.pt
|   |   optimizer.pt
|   |   ...
│   │
│   └─── dataset
│       │   0.pt
│       │   1.pt
│       │   ...
│
└─── config
│   |   trainer.yaml
|
└─── media
│   │
│   └─── episodes
│   |   │   ...
│   │
│   └─── reconstructions
│   |   │   ...
│
└─── scripts
|   |   eval.py
│   │   play.sh
│   │   resume.sh
|   |   ...
|
└─── src
|   |   ...
|
└─── wandb
    |   ...

checkpoints: contains the last checkpoint of the model, its optimizer and the dataset.
media:
- episodes: contains train / test / imagination episodes for visualization purposes.
- reconstructions: contains original frames alongside their reconstructions with the autoencoder.
scripts: from the run folder, you can use the following three scripts.
- eval.py: Launch python ./scripts/eval.py to evaluate the run.
- resume.sh: Launch ./scripts/resume.sh to resume a training that crashed.
- play.sh: Tool to visualize some interesting aspects of the run.
  - Launch ./scripts/play.sh -a to watch the agent play live in the environment. The left panel displays the original environment, and the right panel shows what the agent actually sees through its discrete autoencoder.
  - Launch ./scripts/play.sh -w to unroll live trajectories with your keyboard inputs (i.e. to play in the world model). Note that for faster interaction, the memory of the Transformer is flushed every 20 frames.
  - Launch ./scripts/play.sh to visualize the episodes contained in media/episodes.

Results notebook

The folder results/data/ contains raw scores (for each game, and for each training run) for IRIS and the baselines.

Use the notebook results/results_iris.ipynb to reproduce the figures from the paper.

eloialonso / iris