class ExperienceReplay(object):
def __init__(self, agent, enviroment, batch_size):
self._replay_buffer = TFUniformReplayBuffer(
data_spec=agent.collect_data_spec,
batch_size=enviroment.batch_size,
max_length=100000)
self._random_policy = RandomTFPolicy(enviroment.time_step_spec(),
enviroment.action_spec())
self._fill_buffer(enviroment, self._random_policy, steps=100)
self.dataset = self._replay_buffer.as_dataset(
num_parallel_calls=3,
sample_batch_size=batch_size,
num_steps=2,
single_deterministic_pass=False).prefetch(3)
self.iterator = iter(self.dataset)
def _fill_buffer(self, enviroment, policy, steps):
for _ in range(steps):
self.timestamp_data(enviroment, policy)
def timestamp_data(self, environment, policy):
time_step = environment.current_time_step()
action_step = policy.action(time_step)
next_time_step = environment.step(action_step.action)
timestamp_trajectory = trajectory.from_transition(
time_step, action_step, next_time_step)
self._replay_buffer.add_batch(timestamp_trajectory)
def test_reinforce_agent_learning(env_name):
"""
Extension of the test for an agent playing in the environment to include training.
Note: This does not test that training improves the policy. It simply tests that the training
loop runs effectively.
"""
# Set up environment using default parameters.
# Environment parameters do not affect the test result here.
tf_env, _ = rl_env_from_snc_env(load_scenario(
env_name,
job_gen_seed=10,
override_env_params={'max_episode_length': 25})[1],
discount_factor=0.99)
# Set up a training step counter.
global_step = tf.compat.v1.train.get_or_create_global_step()
# Instantiate a REINFORCE agent
reinforce_agent = create_reinforce_agent(tf_env,
training_step_counter=global_step)
# Instantiate a replay buffer.
replay_buffer = TFUniformReplayBuffer(
data_spec=reinforce_agent.collect_data_spec,
batch_size=tf_env.batch_size,
max_length=1000)
# Initialise the action network weights etc.
reinforce_agent.initialize()
# Use a driver to handle data collection for the agent. This handles a lot of the backend
# TensorFlow set up and solves previous errors with episodes of differing lengths.
collect_driver = DynamicEpisodeDriver(tf_env,
reinforce_agent.collect_policy,
observers=[replay_buffer.add_batch],
num_episodes=2)
# Get the initial states of the agent and environment before training.
time_step = tf_env.reset()
policy_state = reinforce_agent.collect_policy.get_initial_state(
tf_env.batch_size)
# Take a copy of the variables in order to ensure that training does lead to parameter changes.
initial_vars = deepcopy(reinforce_agent.trainable_variables)
assert len(initial_vars) > 0, "Agent has no trainable variables."
# Set up a minimal training loop to simply test training mechanics work.
for _ in range(5):
# Collect experience.
time_step, policy_state = collect_driver.run(time_step=time_step,
policy_state=policy_state)
# Now the replay buffer should have data in it so we can collect the data and train the
# agent.
experience = replay_buffer.gather_all()
reinforce_agent.train(experience)
# Clear the replay buffer and return to play.
replay_buffer.clear()
# Check that training has had some effect
for v1, v2 in zip(initial_vars, reinforce_agent.trainable_variables):
assert not np.allclose(v1.numpy(), v2.numpy())
def __init__(self, experience_spec, batch_size):
# TFUniformReplayBuffer does not support list in spec, we have to do
# some conversion.
self._experience_spec = experience_spec
self._exp_has_list = nest_utils.nest_contains_list(experience_spec)
tuple_experience_spec = nest_utils.nest_list_to_tuple(experience_spec)
self._buffer = TFUniformReplayBuffer(tuple_experience_spec, batch_size)
self._data_iter = None
def collect_step(self, env: tf_py_environment.TFPyEnvironment,
policy: tf_policy.Base,
replay_buffer: TFUniformReplayBuffer):
time_step = env.current_time_step()
action_step = policy.action(time_step)
next_time_step = env.step(action_step.action)
traj = trajectory.from_transition(time_step, action_step,
next_time_step)
replay_buffer.add_batch(traj)
def main():
env = suite_gym.load('Trajectory-v0', gym_kwargs={
'num_dimensions': 2,
'num_observables': 3,
'max_targets': 100,
'max_steps': 5000,
'max_steps_without_target': 5000,
'max_position': 100.0,
'max_acceleration': 10.2,
'max_velocity': 15.0,
'collision_epsilon': 10.0
})
tf_env = tf_py_environment.TFPyEnvironment(env)
agent = RandomAgent(tf_env.time_step_spec(), tf_env.action_spec())
uniform_replay_buffer = TFUniformReplayBuffer(agent.collect_data_spec, batch_size=1)
transitions = []
driver = DynamicStepDriver(
tf_env,
policy=agent.policy,
observers=[uniform_replay_buffer.add_batch],
transition_observers=[transitions.append],
num_steps=500
)
initial_time_step = tf_env.reset()
final_time_step, final_policy_state = driver.run(initial_time_step)
dataset = uniform_replay_buffer.as_dataset()
input_state = []
input_action = []
output_state = []
output_reward = []
for transition in transitions:
input_state.append(tf.concat(tf.nest.flatten(transition[0].observation), axis=-1))
input_action.append(tf.concat(tf.nest.flatten(transition[1].action), axis=-1))
output_state.append(tf.concat(tf.nest.flatten(transition[2].observation), axis=-1))
output_reward.append(tf.concat(tf.nest.flatten(transition[2].reward), axis=-1))
tf_input_state = tf.squeeze(tf.stack(input_state), axis=1)
tf_input_action = tf.squeeze(tf.stack(input_action), axis=1)
tf_output_state = tf.squeeze(tf.stack(output_state), axis=1)
tf_output_reward = tf.stack(output_reward)
# dataset = (features, labels)
# (time_step_before, policy_step_action, time_step_after) = transitions[0]
# observation = time_step_before.observation
# action = policy_step_action.action
# # (discount_, observation_, reward_, step_type_) = time_step_after
# observation_ = time_step_after.observation
pass
def main():
env = suite_gym.load('Trajectory-v0',
gym_kwargs={
'num_dimensions': 2,
'num_observables': 15,
'max_targets': 100,
'max_steps': 5000,
'max_steps_without_target': 5000,
'max_position': 100.0,
'max_acceleration': 10.2,
'max_velocity': 15.0,
'collision_epsilon': 10.0
})
tf_env = tf_py_environment.TFPyEnvironment(env)
agent = RandomAgent(time_step_spec=tf_env.time_step_spec(),
action_spec=tf_env.action_spec())
metric = AverageReturnMetric()
replay_buffer = []
# uniform_replay_buffer = PyUniformReplayBuffer(data_spec=agent.collect_data_spec, capacity=2000)
uniform_replay_buffer = TFUniformReplayBuffer(
data_spec=agent.collect_data_spec, batch_size=1)
# observers = [replay_buffer.append, metric]
# driver = PyDriver(
# env,
# policy=RandomPyPolicy(env.time_step_spec(), env.action_spec()),
# observers=[replay_buffer.append, metric],
# max_steps=2000
# )
# driver = TFDriver(
# tf_env,
# # policy=RandomTFPolicy(tf_env.time_step_spec(), tf_env.action_spec()),
# policy=agent.policy,
# observers=[uniform_replay_buffer],
# max_steps=2000
# )
driver = DynamicStepDriver(
tf_env,
policy=agent.policy,
observers=[uniform_replay_buffer.add_batch], #, metric],
# transition_observers=None,
num_steps=1000)
agent.initialize()
initial_time_step = tf_env.reset()
final_time_step, final_policy_state = driver.run(initial_time_step)
dataset = uniform_replay_buffer.as_dataset()
def collect_step(environment: TFEnvironment, policy: TFPyPolicy,
replay_buffer: TFUniformReplayBuffer):
"""
Coleta uma iteração com o ambiente e devolve o resultado m
:param environment:
:param policy:
:param replay_buffer:
:return:
"""
time_step = environment.current_time_step()
action_step = policy.action(time_step)
next_time_step = environment.step(action_step.action)
traj = trajectory.from_transition(time_step, action_step, next_time_step)
# Add trajectory to the replay buffer
replay_buffer.add_batch(traj)
def __init__(self, agent, enviroment):
self._replay_buffer = TFUniformReplayBuffer(
data_spec=agent.collect_data_spec,
batch_size=enviroment.batch_size,
max_length=50000)
self._random_policy = RandomTFPolicy(train_env.time_step_spec(),
enviroment.action_spec())
self._fill_buffer(train_env, self._random_policy, steps=100)
self.dataset = self._replay_buffer.as_dataset(
num_parallel_calls=3, sample_batch_size=BATCH_SIZE,
num_steps=2).prefetch(3)
self.iterator = iter(self.dataset)
def __init__(self, **kwargs):
self.batch_size = 1
self.tf_agent = kwargs["tf_agent"]
self.replay_buffer = TFUniformReplayBuffer(
self.tf_agent.collect_data_spec,
batch_size=self.batch_size,
max_length=kwargs[MAX_REPLAY_BUFFER_LENGTH])
def compile(self, X_train: np.ndarray, y_train: np.ndarray, lr: float, epsilon: float, gamma: float, imb_ratio: float,
replay_buffer_max_length: int, layers: dict) -> None:
"""
Create the Q-network, agent and policy
Args:
X_train: A np.ndarray for training samples.
y_train: A np.ndarray for the class labels of the training samples.
lr: learn rate for the optimizer (default Adam)
epsilon: Used for the default epsilon greedy policy for choosing a random action.
gamma: The discount factor for learning Q-values
imb_ratio: ratio of imbalance. Used to specifiy reward in the environment
replay_buffer_max_length: Maximum lenght of replay memory.
layers: A dict containing the layers of the Q-Network (eg, conv, dense, rnn, dropout).
"""
dense_layers = layers.get("dense")
conv_layers = layers.get("conv")
dropout_layers = layers.get("dropout")
self.train_env = TFPyEnvironment(ClassifyEnv(X_train, y_train, imb_ratio)) # create a custom environment
q_net = QNetwork(self.train_env.observation_spec(), self.train_env.action_spec(), conv_layer_params=conv_layers,
fc_layer_params=dense_layers, dropout_layer_params=dropout_layers)
optimizer = tf.compat.v1.train.AdamOptimizer(learning_rate=lr)
train_step_counter = tf.Variable(0)
self.agent = DqnAgent(
self.train_env.time_step_spec(),
self.train_env.action_spec(),
q_network=q_net,
optimizer=optimizer,
td_errors_loss_fn=common.element_wise_squared_loss,
train_step_counter=train_step_counter,
gamma=gamma,
epsilon_greedy=epsilon,
)
self.agent.initialize()
self.replay_buffer = TFUniformReplayBuffer(
data_spec=self.agent.collect_data_spec,
batch_size=self.train_env.batch_size,
max_length=replay_buffer_max_length)
def __init__(self, agent, enviroment, batch_size):
self._replay_buffer = TFUniformReplayBuffer(
data_spec=agent.collect_data_spec,
batch_size=enviroment.batch_size,
max_length=50000)
self._random_policy = RandomTFPolicy(enviroment.time_step_spec(),
enviroment.action_spec())
self._fill_buffer(enviroment, self._random_policy, steps=100)
self.dataset = self._replay_buffer.as_dataset(
num_parallel_calls=3,
sample_batch_size=batch_size,
num_steps=2,
single_deterministic_pass=False).prefetch(3)
self.iterator = iter(self.dataset)
def train(agent: DdqnAgent, train_env: TFEnvironment,
replay_buffer: TFUniformReplayBuffer, num_episodes: int,
replay_buffer_batch_size: int, save_path: str, ramdomize_step: int,
validate_step: int):
train_dataset = replay_buffer.as_dataset(
num_parallel_calls=tf.data.experimental.AUTOTUNE,
num_steps=REPLAY_BUFFER_NUM_STEPS,
sample_batch_size=replay_buffer_batch_size)
train_iterator = iter(train_dataset)
# Savers
checkpointer, saver = create_savers(save_path, agent, replay_buffer)
policy_path = os.path.join(save_path, "saved", "policy")
checkpointer.initialize_or_restore()
global_step = 0
episode = 0
tf.print("Aguardando conexão do cliente")
random_policy = create_random_policy(train_env)
collect_episode_data(train_env,
random_policy,
replay_buffer,
repeats=3,
phase="Random")
for episode in range(num_episodes):
tf.print(f"Episódio {episode} iniciado")
# Colect random data
episode_info = collect_episode_data(train_env,
agent.collect_policy,
replay_buffer,
repeats=1)
experience, unused_info = next(train_iterator)
train_loss = agent.train(experience).loss
global_step = agent.train_step_counter.numpy()
tf.print(
f"Episódio {episode} finalizado, com custo {train_loss} e recompensa {episode_info['reward']}"
)
collect_episode_data(train_env,
agent.policy,
replay_buffer,
phase="Inference")
#TODO: Salvar métricas no tensorboard ou outro cara
# Salvar política e agente
checkpointer.save(global_step=global_step)
saver.save(policy_path)
tf.print(
f"Treinamento finalizado no eposiódio {episode} passo {global_step}")
def create_real_replay_buffer(self) -> ReplayBuffer:
"""
Create the replay buffer for storing data from the real environment.
"""
return TFUniformReplayBuffer(
self._agent.collect_policy.trajectory_spec,
batch_size=1,
max_length=self._real_replay_buffer_capacity,
)
def _init_replay_buffer(self, batch_size, data_spec):
self._batch_size = batch_size
buffer_config = {
"batch_size": self._batch_size,
"data_spec": data_spec,
"max_length": 1
}
tf.compat.v2.summary.scalar(name="replay_buffer_size",
data=self._batch_size)
self._replay_buffer = TFReplayBuffer(**buffer_config)
class TFUniformReplayBuffer(TFReplayBufferAbstract):
def _init_replay_buffer(self, batch_size, data_spec):
self._batch_size = batch_size
buffer_config = {
"batch_size": self._batch_size,
"data_spec": data_spec,
"max_length": 1
}
tf.compat.v2.summary.scalar(name="replay_buffer_size",
data=self._batch_size)
self._replay_buffer = TFReplayBuffer(**buffer_config)
def add_batch(self, traj_dict):
"""
add a trajectory to the replay buffer
Params
traj (dict[dim]:numpy): a dict of tensors representing the trajectory to be added it to the replay buffer
"""
collect_spec_dict = self.collect_data_spec._asdict()
traj_tf, traj_spec = build_tf_trajectory(traj_dict, collect_spec_dict)
if not self._replay_buffer:
batch_size = len(traj_dict["observation"])
self._init_replay_buffer(batch_size, traj_spec)
self._replay_buffer.add_batch(traj_tf)
def get_batch(self, batch_size):
if batch_size is None:
batch_size = self._batch_size
# TODO: convert the replay buffer to a dataset and iterate over it
traj, metadata = self._replay_buffer.get_next(
sample_batch_size=batch_size)
return traj, metadata
def replay_actions_across_batch_transition_models(env_model,
actions) -> Trajectory:
"""
Use an open loop policy to apply a sequence of actions to the environment model. This returns
at least one episode per environment batch (the same action sequence is applied to each batch).
"""
open_loop_policy = TFOpenLoopPolicy(env_model.time_step_spec(),
env_model.action_spec(), actions)
buffer = TFUniformReplayBuffer(open_loop_policy.trajectory_spec,
batch_size=env_model.batch_size,
max_length=1000)
driver = TFDriver(
env_model,
open_loop_policy,
observers=[buffer.add_batch],
max_steps=env_model.batch_size * actions.shape[0],
disable_tf_function=True,
)
driver.run(env_model.reset())
trajectories = buffer.gather_all()
return trajectories
def get_replay_buffer(
env: TFPyEnvironment, agent: Union[ReinforceAgent, PPOAgent], max_length: int = 100000
) -> TFUniformReplayBuffer:
"""
Sets up a replay buffer object for use in training the agent.
:param env: TensorFlow environment which provides specifications for use in setting up a replay
buffer.
:param agent: The agent which provides specifications for use in setting up a replay buffer.
:param max_length: The maximum length/capacity of the replay buffer.
:return: A replay buffer (TFUniformReplayBuffer)
"""
replay_buffer = TFUniformReplayBuffer(
data_spec=agent.collect_data_spec,
batch_size=env.batch_size,
max_length=max_length
)
return replay_buffer
class SyncUniformExperienceReplayer(ExperienceReplayer):
"""
For synchronous off-policy training.
Example algorithms: DDPG, SAC
"""
def __init__(self, experience_spec, batch_size):
self._buffer = TFUniformReplayBuffer(experience_spec, batch_size)
self._data_iter = None
def observe(self, exp, env_ids=None):
"""
For the sync driver, `exp` has the shape (`env_batch_size`, ...)
with `num_envs`==1 and `unroll_length`==1. This function always ignores
`env_ids`.
"""
self._buffer.add_batch(exp)
def replay(self, sample_batch_size, mini_batch_length):
if self._data_iter is None:
dataset = self._buffer.as_dataset(
num_parallel_calls=3,
sample_batch_size=sample_batch_size,
num_steps=mini_batch_length).prefetch(3)
self._data_iter = iter(dataset)
return next(self._data_iter)
def replay_all(self):
return self._buffer.gather_all()
def clear(self):
self._buffer.clear()
@property
def batch_size(self):
return self._buffer._batch_size
optimizer,
actor_net,
value_net,
num_epochs=num_epochs,
train_step_counter=global_step,
discount_factor=0.995,
gradient_clipping=0.5,
entropy_regularization=1e-2,
importance_ratio_clipping=0.2,
use_gae=True,
use_td_lambda_return=True)
agent.initialize()
replay_buffer = TFUniformReplayBuffer(data_spec=agent.collect_data_spec,
batch_size=env.batch_size,
max_length=100000)
def compute_avg_return(environment, policy, num_episodes=10):
total_return = 0.0
for _ in range(num_episodes):
time_step = environment.reset()
episode_return = 0.0
while not time_step.is_last():
action_step = policy.action(time_step)
time_step = environment.step(action_step.action)
episode_return += time_step.reward
total_return += episode_return
def _dyke_replay_buffer(env: TFPyEnvironment, agent: DqnAgent,
steps_per_episode: int) -> TFUniformReplayBuffer:
return TFUniformReplayBuffer(data_spec=agent.collect_data_spec,
batch_size=env.batch_size,
max_length=steps_per_episode)
target_categorical_q_network=target_q_net,
target_update_tau=tau,
target_update_period=1,
td_errors_loss_fn=loss,
gamma=gamma,
train_step_counter=train_step
)
agent.initialize()
# 4. Constructing the Replay Memory.
memory_size = 20000
batch_size = 64
replay_buffer = TFUniformReplayBuffer(
data_spec=agent.collect_data_spec,
batch_size=train_env.batch_size,
max_length=memory_size
)
# Initializing Observer of replay buffer to store experiences (trajectories) to memory.
replay_buffer_observer = replay_buffer.add_batch
# Defining Metrics for measuring training progress.
train_metrics = [ AverageReturnMetric(), AverageEpisodeLengthMetric() ]
# 5. Defining initial policy as random to collect enough examples to fill the memory buffer (Training delay).
initial_collect_policy = random_tf_policy.RandomTFPolicy( train_env.time_step_spec(), train_env.action_spec() )
initial_collect_steps = 2000
class ShowProgress:
def build_replay_buffer(self):
"""Build replay buffer."""
return TFUniformReplayBuffer(
data_spec=self.agent.collect_data_spec,
batch_size=1,
max_length=self.replay_buffer_max_length)
class DQNAgent:
def __init__(self) -> None:
"""
A class for training a TF-agent
based on https://www.tensorflow.org/agents/tutorials/1_dqn_tutorial
"""
self.train_env = None # Training environment
self.agent = None # The algorithm used to solve an RL problem is represented by a TF-Agent
self.replay_buffer = None # The replay buffer keeps track of data collected from the environment
self.dataset = None # The agent needs access to the replay buffer via an iterable tf.data.Dataset
self.iterator = None # The iterator of self.dataset
def compile(self, X_train: np.ndarray, y_train: np.ndarray, lr: float, epsilon: float, gamma: float, imb_ratio: float,
replay_buffer_max_length: int, layers: dict) -> None:
"""
Create the Q-network, agent and policy
Args:
X_train: A np.ndarray for training samples.
y_train: A np.ndarray for the class labels of the training samples.
lr: learn rate for the optimizer (default Adam)
epsilon: Used for the default epsilon greedy policy for choosing a random action.
gamma: The discount factor for learning Q-values
imb_ratio: ratio of imbalance. Used to specifiy reward in the environment
replay_buffer_max_length: Maximum lenght of replay memory.
layers: A dict containing the layers of the Q-Network (eg, conv, dense, rnn, dropout).
"""
dense_layers = layers.get("dense")
conv_layers = layers.get("conv")
dropout_layers = layers.get("dropout")
self.train_env = TFPyEnvironment(ClassifyEnv(X_train, y_train, imb_ratio)) # create a custom environment
q_net = QNetwork(self.train_env.observation_spec(), self.train_env.action_spec(), conv_layer_params=conv_layers,
fc_layer_params=dense_layers, dropout_layer_params=dropout_layers)
optimizer = tf.compat.v1.train.AdamOptimizer(learning_rate=lr)
train_step_counter = tf.Variable(0)
self.agent = DqnAgent(
self.train_env.time_step_spec(),
self.train_env.action_spec(),
q_network=q_net,
optimizer=optimizer,
td_errors_loss_fn=common.element_wise_squared_loss,
train_step_counter=train_step_counter,
gamma=gamma,
epsilon_greedy=epsilon,
)
self.agent.initialize()
self.replay_buffer = TFUniformReplayBuffer(
data_spec=self.agent.collect_data_spec,
batch_size=self.train_env.batch_size,
max_length=replay_buffer_max_length)
def fit(self, X_train: np.ndarray, y_train: np.ndarray, epochs: int, batch_size: int, eval_step: int, log_step: int,
collect_steps_per_episode: int) -> None:
"""
Starts the training of the Agent.
Args:
X_train: A np.ndarray for training samples.
y_train: A np.ndarray for the class labels of the training samples.
epochs: Number of epochs to train Agent
batch_size: The Batch Size
eval_step: Evaluate Model each 'eval_step'
log_step: Monitor results of model each 'log_step'
collect_steps_per_episode: Collect a few steps using collect_policy and save to the replay buffer.
"""
self.dataset = self.replay_buffer.as_dataset(
num_parallel_calls=3,
sample_batch_size=batch_size,
num_steps=2).prefetch(3)
self.iterator = iter(self.dataset)
def collect_step(environment, policy, buffer):
time_step = environment.current_time_step()
action_step = policy.action(time_step)
next_time_step = environment.step(action_step.action)
traj = trajectory.from_transition(time_step, action_step, next_time_step)
# Add trajectory to the replay buffer
buffer.add_batch(traj)
def collect_data(env, policy, buffer, steps):
for _ in range(steps):
collect_step(env, policy, buffer)
# (Optional) Optimize by wrapping some of the code in a graph using TF function.
self.agent.train = common.function(self.agent.train)
# Reset the train step
self.agent.train_step_counter.assign(0)
for _ in range(epochs):
#print("epoch: ", _)
# Collect a few steps using collect_policy and save to the replay buffer.
collect_data(self.train_env, self.agent.collect_policy, self.replay_buffer, collect_steps_per_episode)
# Sample a batch of data from the buffer and update the agent's network.
experience, _ = next(self.iterator)
train_loss = self.agent.train(experience).loss
step = self.agent.train_step_counter.numpy()
if step % log_step == 0:
print('step = {0}: loss = {1}'.format(step, train_loss))
if step % eval_step == 0:
metrics = self.compute_metrics(X_train, y_train)
print(metrics)
def compute_metrics(self, X: np.ndarray, y_true: list) -> dict:
"""Compute Metrics for Evaluation"""
# TODO: apply softmax layer for q logits?
q, _ = self.agent._target_q_network (X, training=False)
# y_scores = np.max(q.numpy(), axis=1) # predicted scores (Q-Values)
y_pred = np.argmax(q.numpy(), axis=1) # predicted class label
metrics = custom_metrics(y_true, y_pred)
return metrics
def evaluate(self, X: np.ndarray, y: list, X_train=None, y_train=None) -> dict:
"""
Evaluation of trained Q-network
"""
metrics = self.compute_metrics(X, y)
print("evaluation: ", metrics)
return metrics
def train_agent(
env: TFPyEnvironment,
agent: Union[ReinforceAgent, PPOAgent],
data_collection_driver: DynamicEpisodeDriver,
replay_buffer: TFUniformReplayBuffer,
num_iters: int,
global_step=None,
metrics: Optional[Sequence[tf_metric.TFStepMetric]] = None,
policy_metrics: Optional[Sequence[tf_metric.TFStepMetric]] = None,
policy_summary_writers: Optional[Sequence[tf.summary.SummaryWriter]] = None,
eval_env: Optional[TFPyEnvironment] = None,
eval_summary_writer: Optional[tf.summary.SummaryWriter] = None,
num_eval_episodes: int = 1,
eval_metrics: Optional[List[tf_metric.TFStepMetric]] = None,
per_step_eval_metrics: Optional[List[Any]] = None,
eval_freq: int = 10,
log_freq: int = 5,
save_freq: int = 5,
model_save_path: Optional[str] = None,
tf_log_stream_path: Optional[str] = None) -> None:
"""
Function for putting the pieces together to train and evaluate an agent.
:param env: The environment for which the agent will be trained.
:param agent: The agent to train.
:param data_collection_driver: The driver used for data collection and metric tracking.
:param replay_buffer: Replay buffer in which to store experience.
:param num_iters: The number of training iterations to perform.
:param global_step: A counter of the number of training iterations.
:param metrics: A list of the metrics to track during training.
:param policy_metrics: A list of metrics related to the policy distribution to track during
training.
:param policy_summary_writers: A list of summary writers to facilitate overlaying plots of
policy metrics in TensorBoard.
:param eval_env: The environment in which to play out evaluations of the policy.
:param eval_summary_writer: The summary writer used for evaluation metrics.
:param num_eval_episodes: The number of evaluation episodes to run at each evaluation point.
:param eval_metrics: The metrics to track when evaluating the policy (with episodic resolution).
:param per_step_eval_metrics: The metrics to track when evaluating the policy (with time step
resolution).
:param eval_freq: The number of training iterations between runs of policy evaluation logging.
:param log_freq: The frequency with which to log values to TensorBoard.
:param save_freq: The number of training iterations between model saves.
:param model_save_path: Directory in which to save model checkpoints (weights etc). If None
model will not be saved.
:param tf_log_stream_path:
"""
# Get the initial states of the agent and environment before training.
time_step = env.reset()
policy_state = agent.collect_policy.get_initial_state(env.batch_size)
# Set up the model saving infrastructure if a path to save to is provided.
save_model = bool(model_save_path)
if save_model:
# Ensure that we save all trackable values (i.e. variables) from the TensorFlow Agent.
checkpoint = tf.train.Checkpoint(agent=agent)
# The checkpoint manager enables us to save multiple versions of the check point at
# different training steps. We save the 20 most recent saves to span a wide section of
# training.
checkpoint_manager = tf.train.CheckpointManager(checkpoint, model_save_path, max_to_keep=20)
else:
# Warn the user that training will continue but models will not be saved.
warn("No save directory provided. Model will not be saved.")
if metrics is None:
metrics = []
if per_step_eval_metrics is None:
per_step_eval_metrics = []
# Set up a minimal training loop to simply test training mechanics work.
for i in range(num_iters):
with tf.summary.record_if(lambda: tf.math.equal(global_step % log_freq, 0)):
# Collect experience.
time_step, policy_state = data_collection_driver.run(
time_step=time_step,
policy_state=policy_state
)
# Now the replay buffer should have data in it so we can collect the data and train the
# agent.
experience = replay_buffer.gather_all()
agent.train(experience)
# Clear the replay buffer and return to play.
replay_buffer.clear()
for metric in metrics:
metric.tf_summaries(
train_step=global_step,
step_metrics=metrics[:2]
)
# Run the policy tracking metrics one at a time each on their own summary writer to
# enable shared axes on TensorBoard.
for metric, summary_writer in zip(policy_metrics, policy_summary_writers):
with summary_writer.as_default():
tf.summary.scalar(name=metric.name, data=metric.result(), step=global_step)
if eval_summary_writer and eval_metrics and eval_env:
if i > 0 and global_step % eval_freq == 0:
evaluate_policy(
eval_metrics,
eval_env,
agent.policy,
per_step_metrics=per_step_eval_metrics,
num_episodes=num_eval_episodes,
train_step=global_step,
summary_writer=eval_summary_writer,
summary_prefix="Metrics",
logging=True,
tf_log_stream_path=tf_log_stream_path
)
# Periodically save the model provided that we have the infrastructure in place.
if save_model and i > 0 and (i + 1) % save_freq == 0:
checkpoint_manager.save(i + 1)
if i % (num_iters // 100) == 0:
print(f"\tCompleted: {i / num_iters * 100} %")
checkpoint_manager.save(num_iters)
class SyncUniformExperienceReplayer(ExperienceReplayer):
"""
For synchronous off-policy training.
Example algorithms: DDPG, SAC
"""
def __init__(self, experience_spec, batch_size):
# TFUniformReplayBuffer does not support list in spec, we have to do
# some conversion.
self._experience_spec = experience_spec
self._exp_has_list = nest_utils.nest_contains_list(experience_spec)
tuple_experience_spec = nest_utils.nest_list_to_tuple(experience_spec)
self._buffer = TFUniformReplayBuffer(tuple_experience_spec, batch_size)
self._data_iter = None
def _list_to_tuple(self, exp):
if self._exp_has_list:
return nest_utils.nest_list_to_tuple(exp)
else:
return exp
def _tuple_to_list(self, exp):
if self._exp_has_list:
return nest_utils.nest_tuple_to_list(exp, self._experience_spec)
else:
return exp
def observe(self, exp, env_ids=None):
"""
For the sync driver, `exp` has the shape (`env_batch_size`, ...)
with `num_envs`==1 and `unroll_length`==1. This function always ignores
`env_ids`.
"""
self._buffer.add_batch(self._list_to_tuple(exp))
def replay(self, sample_batch_size, mini_batch_length):
"""Get a random batch.
Args:
sample_batch_size (int): number of sequences
mini_batch_length (int): the length of each sequence
Returns:
Experience: experience batch in batch major (B, T, ...)
tf_uniform_replay_buffer.BufferInfo: information about the batch
"""
if self._data_iter is None:
dataset = self._buffer.as_dataset(
num_parallel_calls=3,
sample_batch_size=sample_batch_size,
num_steps=mini_batch_length).prefetch(3)
self._data_iter = iter(dataset)
exp, info = next(self._data_iter)
return self._tuple_to_list(exp), info
def replay_all(self):
return self._tuple_to_list(self._buffer.gather_all())
def clear(self):
self._buffer.clear()
@property
def batch_size(self):
return self._buffer._batch_size
]
output_layer = Dense(num_actions, activation=None)
cloning_net = Sequential(dense_layers + [output_layer])
optimizer = Adam(learning_rate=learning_rate)
train_step_counter = train_utils.create_train_step()
agent = BehavioralCloningAgent(env.time_step_spec(),
env.action_spec(),
cloning_network=cloning_net,
optimizer=optimizer)
policy = agent.policy
replay_buffer = TFUniformReplayBuffer(data_spec=agent.collect_data_spec,
batch_size=env.batch_size,
max_length=replay_buffer_capacity)
agent.train_step_counter.assign(0)
replay_observer = [replay_buffer.add_batch]
with strategy.scope():
driver = TFDriver(env,
collect_policy,
replay_observer,
max_episodes=100)
average = AverageReturnMetric()
metrics_observer = [average]
metrics_driver = TFRenderDriver(env,
policy,
# Initialize agent
agent.initialize()
# Wrap the training function in a TF graph
agent.train = common.function(agent.train)
# Create game environments: training and evaluation
train_env = TFPyEnvironment(NineMensMorris(agent.policy, discount=DISCOUNT))
eval_env = TFPyEnvironment(NineMensMorris(agent.policy, discount=DISCOUNT))
# Random policy for data collection
random_policy = RandomTFPolicy(time_step_spec=train_env.time_step_spec(),
action_spec=train_env.action_spec())
# Create replay buffer for data collection
replay_buffer = TFUniformReplayBuffer(data_spec=agent.collect_data_spec,
batch_size=train_env.batch_size,
max_length=BUFFER_LENGTH)
# Create driver for the agent
driver = DynamicStepDriver(env=train_env,
policy=agent.collect_policy,
observers=[replay_buffer.add_batch],
num_steps=STEPS_PER_ITER)
# Wrap the run function in a TF graph
driver.run = common.function(driver.run)
# Create driver for the random policy
random_driver = DynamicStepDriver(env=train_env,
policy=random_policy,
observers=[replay_buffer.add_batch],
num_steps=STEPS_PER_ITER)
# Wrap the run function in a TF graph
total_return = 0
for _ in range(num_episodes):
time_step = environment.reset()
episode_return = 0
while not time_step.is_last():
action_step = policy.action(time_step)
time_step = environment.step(action_step.action)
episode_return += time_step.reward
total_return += episode_return
return total_return / num_episodes
# Replay buffer
replay_buffer = TFUniformReplayBuffer(
data_spec=agent.collect_data_spec,
batch_size=train_env.batch_size,
max_length=REPLAY_BUFFER_MAX
)
driver = DynamicStepDriver(
train_env,
agent.collect_policy,
observers=[replay_buffer.add_batch],
num_steps=1
)
dataset = replay_buffer.as_dataset(
num_parallel_calls=3,
sample_batch_size=BATCH_SIZE,
num_steps=2).prefetch(3)
iterator = iter(dataset)
def __init__(self, experience_spec, batch_size):
self._buffer = TFUniformReplayBuffer(experience_spec, batch_size)
self._data_iter = None
def create_replay_buffer(agent: DdqnAgent, environment: TFEnvironment,
max_lenght: int) -> TFUniformReplayBuffer:
return TFUniformReplayBuffer(agent.collect_data_spec,
environment.batch_size,
max_length=max_lenght)
