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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# # Unity ML-Agents Toolkit
import logging
from typing import Dict, List, Deque, Any
import time
import abc
from mlagents.tf_utils import tf
from mlagents import tf_utils
from collections import deque
from mlagents_envs.timers import set_gauge
from mlagents.trainers.tf_policy import TFPolicy
from mlagents.trainers.stats import StatsReporter
from mlagents.trainers.trajectory import Trajectory
from mlagents.trainers.agent_processor import AgentManagerQueue
from mlagents.trainers.brain import BrainParameters
from mlagents.trainers.policy import Policy
from mlagents.trainers.exception import UnityTrainerException
from mlagents_envs.timers import hierarchical_timer
LOGGER = logging.getLogger("mlagents.trainers")
class Trainer(abc.ABC):
"""This class is the base class for the mlagents_envs.trainers"""
def __init__(
self,
brain_name: str,
trainer_parameters: dict,
training: bool,
run_id: str,
reward_buff_cap: int = 1,
):
"""
Responsible for collecting experiences and training a neural network model.
:BrainParameters brain: Brain to be trained.
:dict trainer_parameters: The parameters for the trainer (dictionary).
:bool training: Whether the trainer is set for training.
:str run_id: The identifier of the current run
:int reward_buff_cap:
"""
self.param_keys: List[str] = []
self.brain_name = brain_name
self.run_id = run_id
self.trainer_parameters = trainer_parameters
self.summary_path = trainer_parameters["summary_path"]
self.stats_reporter = StatsReporter(self.summary_path)
self.cumulative_returns_since_policy_update: List[float] = []
self.is_training = training
self._reward_buffer: Deque[float] = deque(maxlen=reward_buff_cap)
self.policy_queues: List[AgentManagerQueue[Policy]] = []
self.trajectory_queues: List[AgentManagerQueue[Trajectory]] = []
self.step: int = 0
self.training_start_time = time.time()
self.summary_freq = self.trainer_parameters["summary_freq"]
self.next_summary_step = self.summary_freq
def _check_param_keys(self):
for k in self.param_keys:
if k not in self.trainer_parameters:
raise UnityTrainerException(
"The hyper-parameter {0} could not be found for the {1} trainer of "
"brain {2}.".format(k, self.__class__, self.brain_name)
)
def write_tensorboard_text(self, key: str, input_dict: Dict[str, Any]) -> None:
"""
Saves text to Tensorboard.
Note: Only works on tensorflow r1.2 or above.
:param key: The name of the text.
:param input_dict: A dictionary that will be displayed in a table on Tensorboard.
"""
try:
with tf.Session(config=tf_utils.generate_session_config()) as sess:
s_op = tf.summary.text(
key,
tf.convert_to_tensor(
([[str(x), str(input_dict[x])] for x in input_dict])
),
)
s = sess.run(s_op)
self.stats_reporter.write_text(s, self.get_step)
except Exception:
LOGGER.info("Could not write text summary for Tensorboard.")
pass
def _dict_to_str(self, param_dict: Dict[str, Any], num_tabs: int) -> str:
"""
Takes a parameter dictionary and converts it to a human-readable string.
Recurses if there are multiple levels of dict. Used to print out hyperaparameters.
param: param_dict: A Dictionary of key, value parameters.
return: A string version of this dictionary.
"""
if not isinstance(param_dict, dict):
return str(param_dict)
else:
append_newline = "\n" if num_tabs > 0 else ""
return append_newline + "\n".join(
[
"\t"
+ " " * num_tabs
+ "{0}:\t{1}".format(
x, self._dict_to_str(param_dict[x], num_tabs + 1)
)
for x in param_dict
]
)
def __str__(self) -> str:
return """Hyperparameters for the {0} of brain {1}: \n{2}""".format(
self.__class__.__name__,
self.brain_name,
self._dict_to_str(self.trainer_parameters, 0),
)
@property
def parameters(self) -> Dict[str, Any]:
"""
Returns the trainer parameters of the trainer.
"""
return self.trainer_parameters
@property
def get_max_steps(self) -> int:
"""
Returns the maximum number of steps. Is used to know when the trainer should be stopped.
:return: The maximum number of steps of the trainer
"""
return int(float(self.trainer_parameters["max_steps"]))
@property
def get_step(self) -> int:
"""
Returns the number of steps the trainer has performed
:return: the step count of the trainer
"""
return self.step
@property
def should_still_train(self) -> bool:
"""
Returns whether or not the trainer should train. A Trainer could
stop training if it wasn't training to begin with, or if max_steps
is reached.
"""
return self.is_training and self.get_step <= self.get_max_steps
@property
def reward_buffer(self) -> Deque[float]:
"""
Returns the reward buffer. The reward buffer contains the cumulative
rewards of the most recent episodes completed by agents using this
trainer.
:return: the reward buffer.
"""
return self._reward_buffer
def _increment_step(self, n_steps: int, name_behavior_id: str) -> None:
"""
Increment the step count of the trainer
:param n_steps: number of steps to increment the step count by
"""
self.step += n_steps
self.next_summary_step = self._get_next_summary_step()
p = self.get_policy(name_behavior_id)
if p:
p.increment_step(n_steps)
def _get_next_summary_step(self) -> int:
"""
Get the next step count that should result in a summary write.
"""
return self.step + (self.summary_freq - self.step % self.summary_freq)
def save_model(self, name_behavior_id: str) -> None:
"""
Saves the model
"""
self.get_policy(name_behavior_id).save_model(self.get_step)
def export_model(self, name_behavior_id: str) -> None:
"""
Exports the model
"""
self.get_policy(name_behavior_id).export_model()
def _write_summary(self, step: int) -> None:
"""
Saves training statistics to Tensorboard.
"""
is_training = "Training." if self.should_still_train else "Not Training."
stats_summary = self.stats_reporter.get_stats_summaries(
"Environment/Cumulative Reward"
)
if stats_summary.num > 0:
LOGGER.info(
" {}: {}: Step: {}. "
"Time Elapsed: {:0.3f} s "
"Mean "
"Reward: {:0.3f}"
". Std of Reward: {:0.3f}. {}".format(
self.run_id,
self.brain_name,
step,
time.time() - self.training_start_time,
stats_summary.mean,
stats_summary.std,
is_training,
)
)
set_gauge(f"{self.brain_name}.mean_reward", stats_summary.mean)
else:
LOGGER.info(
" {}: {}: Step: {}. No episode was completed since last summary. {}".format(
self.run_id, self.brain_name, step, is_training
)
)
self.stats_reporter.write_stats(int(step))
@abc.abstractmethod
def _process_trajectory(self, trajectory: Trajectory) -> None:
"""
Takes a trajectory and processes it, putting it into the update buffer.
:param trajectory: The Trajectory tuple containing the steps to be processed.
"""
self._maybe_write_summary(self.get_step + len(trajectory.steps))
self._increment_step(len(trajectory.steps), trajectory.behavior_id)
def _maybe_write_summary(self, step_after_process: int) -> None:
"""
If processing the trajectory will make the step exceed the next summary write,
write the summary. This logic ensures summaries are written on the update step and not in between.
:param step_after_process: the step count after processing the next trajectory.
"""
if step_after_process >= self.next_summary_step and self.get_step != 0:
self._write_summary(self.next_summary_step)
@abc.abstractmethod
def end_episode(self):
"""
A signal that the Episode has ended. The buffer must be reset.
Get only called when the academy resets.
"""
pass
@abc.abstractmethod
def create_policy(self, brain_parameters: BrainParameters) -> TFPolicy:
"""
Creates policy
"""
pass
@abc.abstractmethod
def add_policy(self, name_behavior_id: str, policy: TFPolicy) -> None:
"""
Adds policy to trainer
"""
pass
@abc.abstractmethod
def get_policy(self, name_behavior_id: str) -> TFPolicy:
"""
Gets policy from trainer
"""
pass
@abc.abstractmethod
def _is_ready_update(self):
"""
Returns whether or not the trainer has enough elements to run update model
:return: A boolean corresponding to wether or not update_model() can be run
"""
return False
@abc.abstractmethod
def _update_policy(self):
"""
Uses demonstration_buffer to update model.
"""
pass
def advance(self) -> None:
"""
Steps the trainer, taking in trajectories and updates if ready.
"""
with hierarchical_timer("process_trajectory"):
for traj_queue in self.trajectory_queues:
# We grab at most the maximum length of the queue.
# This ensures that even if the queue is being filled faster than it is
# being emptied, the trajectories in the queue are on-policy.
for _ in range(traj_queue.maxlen):
try:
t = traj_queue.get_nowait()
self._process_trajectory(t)
except AgentManagerQueue.Empty:
break
if self.should_still_train:
if self._is_ready_update():
with hierarchical_timer("_update_policy"):
self._update_policy()
for q in self.policy_queues:
# Get policies that correspond to the policy queue in question
q.put(self.get_policy(q.behavior_id))
def publish_policy_queue(self, policy_queue: AgentManagerQueue[Policy]) -> None:
"""
Adds a policy queue to the list of queues to publish to when this Trainer
makes a policy update
:param queue: Policy queue to publish to.
"""
self.policy_queues.append(policy_queue)
def subscribe_trajectory_queue(
self, trajectory_queue: AgentManagerQueue[Trajectory]
) -> None:
"""
Adds a trajectory queue to the list of queues for the trainer to ingest Trajectories from.
:param queue: Trajectory queue to publish to.
"""
self.trajectory_queues.append(trajectory_queue)