Function check_env

stable_baselines3/common/env_checker.py:467–547

Check that an environment follows Gym API. This is particularly useful when using a custom environment. Please take a look at https://gymnasium.farama.org/api/env/ for more information about the API. It also optionally check that the environment is compatible with Stable-Baseli

(env: gym.Env, warn: bool = True, skip_render_check: bool = True)

def check_env(env: gym.Env, warn: bool = True, skip_render_check: bool = True) -> None:
    """
    Check that an environment follows Gym API.
    This is particularly useful when using a custom environment.
    Please take a look at https://gymnasium.farama.org/api/env/
    for more information about the API.

    It also optionally check that the environment is compatible with Stable-Baselines.

    :param env: The Gym environment that will be checked
    :param warn: Whether to output additional warnings
        mainly related to the interaction with Stable Baselines
    :param skip_render_check: Whether to skip the checks for the render method.
        True by default (useful for the CI)
    """
    assert isinstance(
        env, gym.Env
    ), "Your environment must inherit from the gymnasium.Env class cf. https://gymnasium.farama.org/api/env/"

    # ============= Check the spaces (observation and action) ================
    _check_spaces(env)

    # Define aliases for convenience
    observation_space = env.observation_space
    action_space = env.action_space

    try:
        env.reset(seed=0)
    except TypeError as e:
        raise TypeError("The reset() method must accept a `seed` parameter") from e

    # Warn the user if needed.
    # A warning means that the environment may run but not work properly with Stable Baselines algorithms
    should_skip = False
    if warn:
        should_skip = _check_unsupported_spaces(env, observation_space, action_space)

        obs_spaces = observation_space.spaces if isinstance(observation_space, spaces.Dict) else {"": observation_space}
        for key, space in obs_spaces.items():
            if isinstance(space, spaces.Box):
                _check_box_obs(space, key)

        # Check for the action space, it may lead to hard-to-debug issues
        if isinstance(action_space, spaces.Box) and (
            np.any(np.abs(action_space.low) != np.abs(action_space.high))
            or np.any(action_space.low != -1)
            or np.any(action_space.high != 1)
        ):
            warnings.warn(
                "We recommend you to use a symmetric and normalized Box action space (range=[-1, 1]) "
                "cf. https://stable-baselines3.readthedocs.io/en/master/guide/rl_tips.html"
            )

        if isinstance(action_space, spaces.Box):
            assert np.all(
                np.isfinite(np.array([action_space.low, action_space.high]))
            ), "Continuous action space must have a finite lower and upper bound"