Randomize LunarLander wind generation at reset to gain statistical independence between episodes

[TobiasKallehauge]

Description

This request changes the way gymnasium/envs/box2d/lunar_lander.py randomly draws a new wind_idx and torque_idx so new indexes are drawn randomly whenever the environment is reset rather than only at initialization. This ensures that the environment is statistically independent between episodes, which it is currently not. Changed the version from v2 to v3 and added a unit test to check that the seed is correctly working in the new version.

Fixes #954

Type of change

• New feature (non-breaking change which adds functionality)

Checklist:

• I have run the pre-commit checks with pre-commit run --all-files (see CONTRIBUTING.md instructions to set it up)
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[Kallinteris-Andreas]

We will also need Unit Testing to validate the changes.

[pseudo-rnd-thoughts]

@TobiasKallehauge this seems to pass all of our internal testing.
As this effects an agent's performance, we should update the environment's version number and add a note to the environment's docstring in version control about the reason for the change.

Then I think we should be go to merge

[TobiasKallehauge]

I committed the version change to the documentation and updated the default version used for tests. Let me know if something else should be changed.

[Kallinteris-Andreas]

I want to see a unit test validating the change.

also Bump the version in registration

[pseudo-rnd-thoughts]

@Kallinteris-Andreas What do you mean?

@TobiasKallehauge Could you add a new test in tests/envs/test_env_implementations.py that using different reset(seed) will cause wind_idx and torque_idx to change. (Probably use known seeds to avoid future randomness issues)

You need to change gymnasium/envs/__init__.py on the lunarlander registration to be v3 not v2

[TobiasKallehauge]

I added the unit test now, and the seed works as expected - I hope the test complies with your standards.

There was still an error in the previous commit for the version due to changing the version number but maybe the new one will pass after changing the tests

[TobiasKallehauge]

There seems to be a few more places where the version number is referenced:

• gymnasium/wrappers/rendering.py
• docs/tutorials/gymnasium_basics/vector_envs_tutorial.py

Right now gymnasium/wrappers/rendering.py is throwing an error. There are also some markdown files where it is references:

• docs/index.md
• docs/introduction/migration_guide.md
• docs/introduction/basic_usage.md

I will update the version in all these places (including in the markdown files) - let me know if this is wrong

[Kallinteris-Andreas]

Overall this looks good to me.

[pseudo-rnd-thoughts]

Thanks for the PR @TobiasKallehauge and your rapid responses

[TobiasKallehauge]

Thanks to you as well! I am happy to contribute