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77 行
3.0 KiB
77 行
3.0 KiB
# # Unity ML-Agents Toolkit
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import logging
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from typing import Dict
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from collections import defaultdict
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from mlagents.trainers.tf_policy import TFPolicy
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from mlagents.trainers.buffer import AgentBuffer
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from mlagents.trainers.trainer import Trainer, UnityTrainerException
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from mlagents.trainers.components.reward_signals import RewardSignalResult
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LOGGER = logging.getLogger("mlagents.trainers")
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RewardSignalResults = Dict[str, RewardSignalResult]
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class RLTrainer(Trainer): # pylint: disable=abstract-method
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"""
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This class is the base class for trainers that use Reward Signals.
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"""
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def __init__(self, *args, **kwargs):
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super(RLTrainer, self).__init__(*args, **kwargs)
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# Make sure we have at least one reward_signal
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if not self.trainer_parameters["reward_signals"]:
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raise UnityTrainerException(
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"No reward signals were defined. At least one must be used with {}.".format(
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self.__class__.__name__
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)
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)
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# collected_rewards is a dictionary from name of reward signal to a dictionary of agent_id to cumulative reward
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# used for reporting only. We always want to report the environment reward to Tensorboard, regardless
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# of what reward signals are actually present.
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self.collected_rewards: Dict[str, Dict[str, int]] = {
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"environment": defaultdict(lambda: 0)
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}
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self.update_buffer: AgentBuffer = AgentBuffer()
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self.episode_steps: Dict[str, int] = defaultdict(lambda: 0)
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def end_episode(self) -> None:
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"""
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A signal that the Episode has ended. The buffer must be reset.
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Get only called when the academy resets.
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"""
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for agent_id in self.episode_steps:
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self.episode_steps[agent_id] = 0
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for rewards in self.collected_rewards.values():
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for agent_id in rewards:
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rewards[agent_id] = 0
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def _update_end_episode_stats(self, agent_id: str, policy: TFPolicy) -> None:
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self.episode_steps[agent_id] = 0
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for name, rewards in self.collected_rewards.items():
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if name == "environment":
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self.cumulative_returns_since_policy_update.append(
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rewards.get(agent_id, 0)
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)
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self.reward_buffer.appendleft(rewards.get(agent_id, 0))
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rewards[agent_id] = 0
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else:
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self.stats_reporter.add_stat(
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policy.reward_signals[name].stat_name, rewards.get(agent_id, 0)
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)
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rewards[agent_id] = 0
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def clear_update_buffer(self) -> None:
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"""
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Clear the buffers that have been built up during inference.
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"""
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self.update_buffer.reset_agent()
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def advance(self) -> None:
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"""
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Steps the trainer, taking in trajectories and updates if ready
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"""
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super().advance()
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if not self.is_training:
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self.clear_update_buffer()
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