63 lines
2.0 KiB
Python
63 lines
2.0 KiB
Python
"""``StickyAction`` wrapper - There is a probability that the action is taken again."""
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from __future__ import annotations
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from typing import Any
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import gymnasium as gym
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from gymnasium.core import ActType, ObsType
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from gymnasium.error import InvalidProbability
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__all__ = ["StickyActionV0"]
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class StickyActionV0(
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gym.ActionWrapper[ObsType, ActType, ActType], gym.utils.RecordConstructorArgs
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):
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"""Wrapper which adds a probability of repeating the previous action.
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This wrapper follows the implementation proposed by `Machado et al., 2018 <https://arxiv.org/pdf/1709.06009.pdf>`_
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in Section 5.2 on page 12.
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"""
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def __init__(
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self, env: gym.Env[ObsType, ActType], repeat_action_probability: float
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):
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"""Initialize StickyAction wrapper.
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Args:
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env (Env): the wrapped environment
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repeat_action_probability (int | float): a probability of repeating the old action.
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"""
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if not 0 <= repeat_action_probability < 1:
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raise InvalidProbability(
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f"repeat_action_probability should be in the interval [0,1). Received {repeat_action_probability}"
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)
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gym.utils.RecordConstructorArgs.__init__(
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self, repeat_action_probability=repeat_action_probability
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)
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gym.ActionWrapper.__init__(self, env)
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self.repeat_action_probability = repeat_action_probability
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self.last_action: ActType | None = None
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def reset(
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self, *, seed: int | None = None, options: dict[str, Any] | None = None
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) -> tuple[ObsType, dict[str, Any]]:
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"""Reset the environment."""
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self.last_action = None
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return super().reset(seed=seed, options=options)
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def action(self, action: ActType) -> ActType:
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"""Execute the action."""
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if (
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self.last_action is not None
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and self.np_random.uniform() < self.repeat_action_probability
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):
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action = self.last_action
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self.last_action = action
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return action
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