Description

[](https://badge.fury.io/py/gymnasium) [](https://badge.fury.io/py/gymnasium) [](https://arxiv.org/abs/2407.17032) [](https://pre-commit.com/) [](https://github.com/Farama-Foundation/Gymnasium/blob/main/LICENSE) [](https://github.com/psf/black) <p align="center"> <a href="https://gymnasium.farama.org/" target = "_blank"> <img src="https://raw.githubusercontent.com/Farama-Foundation/Gymnasium/main/gymnasium-text.png" width="500px" /> </a> </p> Gymnasium is an open source Python library for developing and comparing reinforcement learning algorithms by providing a standard API to communicate between learning algorithms and environments, as well as a standard set of environments compliant with that API. This is a fork of OpenAI's [Gym](https://github.com/openai/gym) library by its maintainers (OpenAI handed over maintenance a few years ago to an outside team), and is where future maintenance will occur going forward. The documentation website is at [gymnasium.farama.org](https://gymnasium.farama.org), and we have a public discord server (which we also use to coordinate development work) that you can join here: https://discord.gg/bnJ6kubTg6 ## Environments Gymnasium includes the following families of environments along with a wide variety of third-party environments * [Classic Control](https://gymnasium.farama.org/environments/classic_control/) - These are classic reinforcement learning based on real-world problems and physics. * [Box2D](https://gymnasium.farama.org/environments/box2d/) - These environments all involve toy games based around physics control, using box2d based physics and PyGame-based rendering * [Toy Text](https://gymnasium.farama.org/environments/toy_text/) - These environments are designed to be extremely simple, with small discrete state and action spaces, and hence easy to learn. As a result, they are suitable for debugging implementations of reinforcement learning algorithms. * [MuJoCo](https://gymnasium.farama.org/environments/mujoco/) - A physics engine based environments with multi-joint control which are more complex than the Box2D environments. * [Atari](https://ale.farama.org/) - Emulator of Atari 2600 ROMs simulated that have a high range of complexity for agents to learn. * [Third-party](https://gymnasium.farama.org/environments/third_party_environments/) - A number of environments have been created that are compatible with the Gymnasium API. Be aware of the version that the software was created for and use the `apply_env_compatibility` in `gymnasium.make` if necessary. ## Installation To install the base Gymnasium library, use `pip install gymnasium` This does not include dependencies for all families of environments (there's a massive number, and some can be problematic to install on certain systems). You can install these dependencies for one family like `pip install "gymnasium[atari]"` or use `pip install "gymnasium[all]"` to install all dependencies. We support and test for Python 3.10, 3.11, 3.12 and 3.13 on Linux and macOS. We will accept PRs related to Windows, but do not officially support it. ## API The Gymnasium API models environments as simple Python `env` classes. Creating environment instances and interacting with them is very simple- here's an example using the "CartPole-v1" environment: ```python import gymnasium as gym env = gym.make("CartPole-v1") observation, info = env.reset(seed=42) for _ in range(1000): action = env.action_space.sample() observation, reward, terminated, truncated, info = env.step(action) if terminated or truncated: observation, info = env.reset() env.close() ``` ## Notable Related Libraries Please note that this is an incomplete list, and just includes libraries that the maintainers most commonly point newcomers to when asked for recommendations. * [CleanRL](https://github.com/vwxyzjn/cleanrl) is a learning library based on the Gymnasium API. It is designed to cater to newer people in the field and provides very good reference implementations. * [PettingZoo](https://github.com/Farama-Foundation/PettingZoo) is a multi-agent version of Gymnasium with a number of implemented environments, i.e. multi-agent Atari environments. * The Farama Foundation also has a collection of many other [environments](https://farama.org/projects) that are maintained by the same team as Gymnasium and use the Gymnasium API. ## Environment Versioning Gymnasium keeps strict versioning for reproducibility reasons. All environments end in a suffix like "-v0". When changes are made to environm