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* Add test for channel-first environments * Add support for channel-first envs, including more tests * Update changelog * Run black * Run black, again * Improve NatureCNN error message * Update image checks and FrameStack wrapper * Update tests * Update docs * Run isort * Reformat * Fixes: avoid breaking changes for non-image env * Add additional checks * Update docstring Co-authored-by: Antonin RAFFIN <antonin.raffin@ensta.org>
83 lines
2.8 KiB
ReStructuredText
83 lines
2.8 KiB
ReStructuredText
.. _custom_env:
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Using Custom Environments
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==========================
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To use the rl baselines with custom environments, they just need to follow the *gym* interface.
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That is to say, your environment must implement the following methods (and inherits from OpenAI Gym Class):
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.. note::
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If you are using images as input, the input values must be in [0, 255] and np.uint8 as the observation
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is normalized (dividing by 255 to have values in [0, 1]) when using CNN policies. Images can be either
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channel-first or channel-last.
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.. code-block:: python
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import gym
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from gym import spaces
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class CustomEnv(gym.Env):
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"""Custom Environment that follows gym interface"""
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metadata = {'render.modes': ['human']}
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def __init__(self, arg1, arg2, ...):
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super(CustomEnv, self).__init__()
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# Define action and observation space
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# They must be gym.spaces objects
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# Example when using discrete actions:
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self.action_space = spaces.Discrete(N_DISCRETE_ACTIONS)
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# Example for using image as input (can be channel-first or channel-last):
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self.observation_space = spaces.Box(low=0, high=255,
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shape=(HEIGHT, WIDTH, N_CHANNELS), dtype=np.uint8)
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def step(self, action):
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...
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return observation, reward, done, info
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def reset(self):
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...
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return observation # reward, done, info can't be included
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def render(self, mode='human'):
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...
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def close (self):
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...
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Then you can define and train a RL agent with:
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.. code-block:: python
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# Instantiate the env
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env = CustomEnv(arg1, ...)
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# Define and Train the agent
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model = A2C('CnnPolicy', env).learn(total_timesteps=1000)
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To check that your environment follows the gym interface, please use:
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.. code-block:: python
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from stable_baselines3.common.env_checker import check_env
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env = CustomEnv(arg1, ...)
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# It will check your custom environment and output additional warnings if needed
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check_env(env)
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We have created a `colab notebook <https://colab.research.google.com/github/araffin/rl-tutorial-jnrr19/blob/master/5_custom_gym_env.ipynb>`_ for
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a concrete example of creating a custom environment.
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You can also find a `complete guide online <https://github.com/openai/gym/blob/master/docs/creating-environments.md>`_
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on creating a custom Gym environment.
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Optionally, you can also register the environment with gym,
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that will allow you to create the RL agent in one line (and use ``gym.make()`` to instantiate the env).
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In the project, for testing purposes, we use a custom environment named ``IdentityEnv``
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defined `in this file <https://github.com/hill-a/stable-baselines/blob/master/stable_baselines/common/identity_env.py>`_.
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An example of how to use it can be found `here <https://github.com/hill-a/stable-baselines/blob/master/tests/test_identity.py>`_.
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