Unity 机器学习代理工具包 (ML-Agents) 是一个开源项目,它使游戏和模拟能够作为训练智能代理的环境。
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import sys
from typing import List, Dict, Deque, TypeVar, Generic
from collections import defaultdict, Counter, deque
from mlagents.trainers.trajectory import Trajectory, AgentExperience
from mlagents.trainers.brain import BrainInfo
from mlagents.trainers.tf_policy import TFPolicy
from mlagents.trainers.policy import Policy
from mlagents.trainers.action_info import ActionInfoOutputs
from mlagents.trainers.stats import StatsReporter
T = TypeVar("T")
class AgentProcessor:
"""
AgentProcessor contains a dictionary per-agent trajectory buffers. The buffers are indexed by agent_id.
Buffer also contains an update_buffer that corresponds to the buffer used when updating the model.
One AgentProcessor should be created per agent group.
"""
def __init__(
self,
policy: TFPolicy,
behavior_id: str,
stats_reporter: StatsReporter,
max_trajectory_length: int = sys.maxsize,
):
"""
Create an AgentProcessor.
:param trainer: Trainer instance connected to this AgentProcessor. Trainer is given trajectory
when it is finished.
:param policy: Policy instance associated with this AgentProcessor.
:param max_trajectory_length: Maximum length of a trajectory before it is added to the trainer.
:param stats_category: The category under which to write the stats. Usually, this comes from the Trainer.
"""
self.experience_buffers: Dict[str, List[AgentExperience]] = defaultdict(list)
self.last_brain_info: Dict[str, BrainInfo] = {}
self.last_take_action_outputs: Dict[str, ActionInfoOutputs] = {}
# Note: this is needed until we switch to AgentExperiences as the data input type.
# We still need some info from the policy (memories, previous actions)
# that really should be gathered by the env-manager.
self.policy = policy
self.episode_steps: Counter = Counter()
self.episode_rewards: Dict[str, float] = defaultdict(float)
self.stats_reporter = stats_reporter
self.max_trajectory_length = max_trajectory_length
self.trajectory_queues: List[AgentManagerQueue[Trajectory]] = []
self.behavior_id = behavior_id
def add_experiences(
self,
curr_info: BrainInfo,
next_info: BrainInfo,
take_action_outputs: ActionInfoOutputs,
) -> None:
"""
Adds experiences to each agent's experience history.
:param curr_info: current BrainInfo.
:param next_info: next BrainInfo.
:param take_action_outputs: The outputs of the Policy's get_action method.
"""
if take_action_outputs:
self.stats_reporter.add_stat(
"Policy/Entropy", take_action_outputs["entropy"].mean()
)
self.stats_reporter.add_stat(
"Policy/Learning Rate", take_action_outputs["learning_rate"]
)
for agent_id in curr_info.agents:
self.last_brain_info[agent_id] = curr_info
self.last_take_action_outputs[agent_id] = take_action_outputs
# Store the environment reward
tmp_environment_reward = next_info.rewards
for next_idx, agent_id in enumerate(next_info.agents):
stored_info = self.last_brain_info.get(agent_id, None)
if stored_info is not None:
stored_take_action_outputs = self.last_take_action_outputs[agent_id]
idx = stored_info.agents.index(agent_id)
obs = []
if not stored_info.local_done[idx]:
for i, _ in enumerate(stored_info.visual_observations):
obs.append(stored_info.visual_observations[i][idx])
if self.policy.use_vec_obs:
obs.append(stored_info.vector_observations[idx])
if self.policy.use_recurrent:
memory = self.policy.retrieve_memories([agent_id])[0, :]
else:
memory = None
done = next_info.local_done[next_idx]
max_step = next_info.max_reached[next_idx]
# Add the outputs of the last eval
action = stored_take_action_outputs["action"][idx]
if self.policy.use_continuous_act:
action_pre = stored_take_action_outputs["pre_action"][idx]
else:
action_pre = None
action_probs = stored_take_action_outputs["log_probs"][idx]
action_masks = stored_info.action_masks[idx]
prev_action = self.policy.retrieve_previous_action([agent_id])[0, :]
experience = AgentExperience(
obs=obs,
reward=tmp_environment_reward[next_idx],
done=done,
action=action,
action_probs=action_probs,
action_pre=action_pre,
action_mask=action_masks,
prev_action=prev_action,
max_step=max_step,
memory=memory,
)
# Add the value outputs if needed
self.experience_buffers[agent_id].append(experience)
self.episode_rewards[agent_id] += tmp_environment_reward[next_idx]
if (
next_info.local_done[next_idx]
or (
len(self.experience_buffers[agent_id])
>= self.max_trajectory_length
)
) and len(self.experience_buffers[agent_id]) > 0:
# Make next AgentExperience
next_obs = []
for i, _ in enumerate(next_info.visual_observations):
next_obs.append(next_info.visual_observations[i][next_idx])
if self.policy.use_vec_obs:
next_obs.append(next_info.vector_observations[next_idx])
trajectory = Trajectory(
steps=self.experience_buffers[agent_id],
agent_id=agent_id,
next_obs=next_obs,
behavior_id=self.behavior_id,
)
for traj_queue in self.trajectory_queues:
traj_queue.put(trajectory)
self.experience_buffers[agent_id] = []
if next_info.local_done[next_idx]:
self.stats_reporter.add_stat(
"Environment/Cumulative Reward",
self.episode_rewards.get(agent_id, 0),
)
self.stats_reporter.add_stat(
"Environment/Episode Length",
self.episode_steps.get(agent_id, 0),
)
del self.episode_steps[agent_id]
del self.episode_rewards[agent_id]
elif not next_info.local_done[next_idx]:
self.episode_steps[agent_id] += 1
self.policy.save_previous_action(
curr_info.agents, take_action_outputs["action"]
)
def publish_trajectory_queue(
self, trajectory_queue: "AgentManagerQueue[Trajectory]"
) -> None:
"""
Adds a trajectory queue to the list of queues to publish to when this AgentProcessor
assembles a Trajectory
:param trajectory_queue: Trajectory queue to publish to.
"""
self.trajectory_queues.append(trajectory_queue)
class AgentManagerQueue(Generic[T]):
"""
Queue used by the AgentManager. Note that we make our own class here because in most implementations
deque is sufficient and faster. However, if we want to switch to multiprocessing, we'll need to change
out this implementation.
"""
class Empty(Exception):
"""
Exception for when the queue is empty.
"""
pass
def __init__(self, behavior_id: str):
"""
Initializes an AgentManagerQueue. Note that we can give it a behavior_id so that it can be identified
separately from an AgentManager.
"""
self.queue: Deque[T] = deque()
self.behavior_id = behavior_id
def empty(self) -> bool:
return len(self.queue) == 0
def get_nowait(self) -> T:
try:
return self.queue.popleft()
except IndexError:
raise self.Empty("The AgentManagerQueue is empty.")
def put(self, item: T) -> None:
self.queue.append(item)
class AgentManager(AgentProcessor):
"""
An AgentManager is an AgentProcessor that also holds a single trajectory and policy queue.
Note: this leaves room for adding AgentProcessors that publish multiple trajectory queues.
"""
def __init__(
self,
policy: TFPolicy,
behavior_id: str,
stats_reporter: StatsReporter,
max_trajectory_length: int = sys.maxsize,
):
super().__init__(policy, behavior_id, stats_reporter, max_trajectory_length)
self.trajectory_queue: AgentManagerQueue[Trajectory] = AgentManagerQueue(
self.behavior_id
)
self.policy_queue: AgentManagerQueue[Policy] = AgentManagerQueue(
self.behavior_id
)
self.publish_trajectory_queue(self.trajectory_queue)