[Question] Do I need to have gym installed in addition to gymnasium in order to run the lunar lander example?

[jim-rothrock]

❓ Question

I am running Ubuntu 22.04.5 LTS, and have used pip to install the following packages:

• gymnasium
• gymnasium[box2d]
• stable-baselines3[extra]
• rl_zoo3

When I run the following

python3 enjoy.py --algo ppo --env CartPole-v1

it works as expected. However, when I run

python3 enjoy.py --algo ppo --env LunarLander-v2

I get the following:

Loading latest experiment, id=1 Loading rl-trained-agents/ppo/LunarLander-v2_1/LunarLander-v2.zip Traceback (most recent call last): File "/home/jimr/.local/lib/python3.10/site-packages/rl_zoo3/enjoy.py", line 276, in enjoy() File "/home/jimr/.local/lib/python3.10/site-packages/rl_zoo3/enjoy.py", line 192, in enjoy model = ALGOS[algo].load(model_path, custom_objects=custom_objects, device=args.device, **kwargs) File "/home/jimr/.local/lib/python3.10/site-packages/stable_baselines3/common/base_class.py", line 680, in load data, params, pytorch_variables = load_from_zip_file( File "/home/jimr/.local/lib/python3.10/site-packages/stable_baselines3/common/save_util.py", line 434, in load_from_zip_file data = json_to_data(json_data, custom_objects=custom_objects) File "/home/jimr/.local/lib/python3.10/site-packages/stable_baselines3/common/save_util.py", line 165, in json_to_data deserialized_object = cloudpickle.loads(base64_object) ModuleNotFoundError: No module named 'gym'

Do I need to install gym in addition to gymnasium? I am concerned that installing both will lead to incompatibilities.

Checklist

• [X] I have checked that there is no similar issue in the repo
• [X] I have read the SB3 documentation
• [X] I have read the RL Zoo documentation
• [X] If code there is, it is minimal and working
• [X] If code there is, it is formatted using the markdown code blocks for both code and stack traces.

[araffin]

Hello, For running some pretrained agents, you might need gym indeed (0.21), but it should not be needed for using the rest of RL zoo. However, if you retrain a lunar lander model, only Gymnasium is enough.