def train_eval(
root_dir,
env_name='HalfCheetah-v2',
# Training params
num_iterations=1600,
actor_fc_layers=(64, 64),
value_fc_layers=(64, 64),
learning_rate=3e-4,
collect_sequence_length=2048,
minibatch_size=64,
num_epochs=10,
# Agent params
importance_ratio_clipping=0.2,
lambda_value=0.95,
discount_factor=0.99,
entropy_regularization=0.,
value_pred_loss_coef=0.5,
use_gae=True,
use_td_lambda_return=True,
gradient_clipping=0.5,
value_clipping=None,
# Replay params
reverb_port=None,
replay_capacity=10000,
# Others
policy_save_interval=5000,
summary_interval=1000,
eval_interval=10000,
eval_episodes=100,
debug_summaries=False,
summarize_grads_and_vars=False):
"""Trains and evaluates PPO (Importance Ratio Clipping).
Args:
root_dir: Main directory path where checkpoints, saved_models, and summaries
will be written to.
env_name: Name for the Mujoco environment to load.
num_iterations: The number of iterations to perform collection and training.
actor_fc_layers: List of fully_connected parameters for the actor network,
where each item is the number of units in the layer.
value_fc_layers: : List of fully_connected parameters for the value network,
where each item is the number of units in the layer.
learning_rate: Learning rate used on the Adam optimizer.
collect_sequence_length: Number of steps to take in each collect run.
minibatch_size: Number of elements in each mini batch. If `None`, the entire
collected sequence will be treated as one batch.
num_epochs: Number of iterations to repeat over all collected data per data
collection step. (Schulman,2017) sets this to 10 for Mujoco, 15 for
Roboschool and 3 for Atari.
importance_ratio_clipping: Epsilon in clipped, surrogate PPO objective. For
more detail, see explanation at the top of the doc.
lambda_value: Lambda parameter for TD-lambda computation.
discount_factor: Discount factor for return computation. Default to `0.99`
which is the value used for all environments from (Schulman, 2017).
entropy_regularization: Coefficient for entropy regularization loss term.
Default to `0.0` because no entropy bonus was used in (Schulman, 2017).
value_pred_loss_coef: Multiplier for value prediction loss to balance with
policy gradient loss. Default to `0.5`, which was used for all
environments in the OpenAI baseline implementation. This parameters is
irrelevant unless you are sharing part of actor_net and value_net. In that
case, you would want to tune this coeeficient, whose value depends on the
network architecture of your choice.
use_gae: If True (default False), uses generalized advantage estimation for
computing per-timestep advantage. Else, just subtracts value predictions
from empirical return.
use_td_lambda_return: If True (default False), uses td_lambda_return for
training value function; here: `td_lambda_return = gae_advantage +
value_predictions`. `use_gae` must be set to `True` as well to enable TD
-lambda returns. If `use_td_lambda_return` is set to True while
`use_gae` is False, the empirical return will be used and a warning will
be logged.
gradient_clipping: Norm length to clip gradients.
value_clipping: Difference between new and old value predictions are clipped
to this threshold. Value clipping could be helpful when training
very deep networks. Default: no clipping.
reverb_port: Port for reverb server, if None, use a randomly chosen unused
port.
replay_capacity: The maximum number of elements for the replay buffer. Items
will be wasted if this is smalled than collect_sequence_length.
policy_save_interval: How often, in train_steps, the policy will be saved.
summary_interval: How often to write data into Tensorboard.
eval_interval: How often to run evaluation, in train_steps.
eval_episodes: Number of episodes to evaluate over.
debug_summaries: Boolean for whether to gather debug summaries.
summarize_grads_and_vars: If true, gradient summaries will be written.
"""
collect_env = suite_mujoco.load(env_name)
eval_env = suite_mujoco.load(env_name)
num_environments = 1
observation_tensor_spec, action_tensor_spec, time_step_tensor_spec = (
spec_utils.get_tensor_specs(collect_env))
# TODO(b/172267869): Remove this conversion once TensorNormalizer stops
# converting float64 inputs to float32.
observation_tensor_spec = tf.TensorSpec(
dtype=tf.float32, shape=observation_tensor_spec.shape)
train_step = train_utils.create_train_step()
actor_net_builder = ppo_actor_network.PPOActorNetwork()
actor_net = actor_net_builder.create_sequential_actor_net(
actor_fc_layers, action_tensor_spec)
value_net = value_network.ValueNetwork(
observation_tensor_spec,
fc_layer_params=value_fc_layers,
kernel_initializer=tf.keras.initializers.Orthogonal())
current_iteration = tf.Variable(0, dtype=tf.int64)
def learning_rate_fn():
# Linearly decay the learning rate.
return learning_rate * (1 - current_iteration / num_iterations)
agent = ppo_clip_agent.PPOClipAgent(
time_step_tensor_spec,
action_tensor_spec,
optimizer=tf.keras.optimizers.Adam(
learning_rate=learning_rate_fn, epsilon=1e-5),
actor_net=actor_net,
value_net=value_net,
importance_ratio_clipping=importance_ratio_clipping,
lambda_value=lambda_value,
discount_factor=discount_factor,
entropy_regularization=entropy_regularization,
value_pred_loss_coef=value_pred_loss_coef,
# This is a legacy argument for the number of times we repeat the data
# inside of the train function, incompatible with mini batch learning.
# We set the epoch number from the replay buffer and tf.Data instead.
num_epochs=1,
use_gae=use_gae,
use_td_lambda_return=use_td_lambda_return,
gradient_clipping=gradient_clipping,
value_clipping=value_clipping,
# TODO(b/150244758): Default compute_value_and_advantage_in_train to False
# after Reverb open source.
compute_value_and_advantage_in_train=False,
# Skips updating normalizers in the agent, as it's handled in the learner.
update_normalizers_in_train=False,
debug_summaries=debug_summaries,
summarize_grads_and_vars=summarize_grads_and_vars,
train_step_counter=train_step)
agent.initialize()
reverb_server = reverb.Server(
[
reverb.Table( # Replay buffer storing experience for training.
name='training_table',
sampler=reverb.selectors.Fifo(),
remover=reverb.selectors.Fifo(),
rate_limiter=reverb.rate_limiters.MinSize(1),
max_size=replay_capacity,
max_times_sampled=1,
),
reverb.Table( # Replay buffer storing experience for normalization.
name='normalization_table',
sampler=reverb.selectors.Fifo(),
remover=reverb.selectors.Fifo(),
rate_limiter=reverb.rate_limiters.MinSize(1),
max_size=replay_capacity,
max_times_sampled=1,
)
],
port=reverb_port)
# Create the replay buffer.
reverb_replay_train = reverb_replay_buffer.ReverbReplayBuffer(
agent.collect_data_spec,
sequence_length=collect_sequence_length,
table_name='training_table',
server_address='localhost:{}'.format(reverb_server.port),
# The only collected sequence is used to populate the batches.
max_cycle_length=1,
rate_limiter_timeout_ms=1000)
reverb_replay_normalization = reverb_replay_buffer.ReverbReplayBuffer(
agent.collect_data_spec,
sequence_length=collect_sequence_length,
table_name='normalization_table',
server_address='localhost:{}'.format(reverb_server.port),
# The only collected sequence is used to populate the batches.
max_cycle_length=1,
rate_limiter_timeout_ms=1000)
rb_observer = reverb_utils.ReverbTrajectorySequenceObserver(
reverb_replay_train.py_client, ['training_table', 'normalization_table'],
sequence_length=collect_sequence_length,
stride_length=collect_sequence_length)
saved_model_dir = os.path.join(root_dir, learner.POLICY_SAVED_MODEL_DIR)
collect_env_step_metric = py_metrics.EnvironmentSteps()
learning_triggers = [
triggers.PolicySavedModelTrigger(
saved_model_dir,
agent,
train_step,
interval=policy_save_interval,
metadata_metrics={
triggers.ENV_STEP_METADATA_KEY: collect_env_step_metric
}),
triggers.StepPerSecondLogTrigger(train_step, interval=summary_interval),
]
def training_dataset_fn():
return reverb_replay_train.as_dataset(
sample_batch_size=num_environments,
sequence_preprocess_fn=agent.preprocess_sequence)
def normalization_dataset_fn():
return reverb_replay_normalization.as_dataset(
sample_batch_size=num_environments,
sequence_preprocess_fn=agent.preprocess_sequence)
agent_learner = ppo_learner.PPOLearner(
root_dir,
train_step,
agent,
experience_dataset_fn=training_dataset_fn,
normalization_dataset_fn=normalization_dataset_fn,
num_samples=1,
num_epochs=num_epochs,
minibatch_size=minibatch_size,
shuffle_buffer_size=collect_sequence_length,
triggers=learning_triggers)
tf_collect_policy = agent.collect_policy
collect_policy = py_tf_eager_policy.PyTFEagerPolicy(
tf_collect_policy, use_tf_function=True)
collect_actor = actor.Actor(
collect_env,
collect_policy,
train_step,
steps_per_run=collect_sequence_length,
observers=[rb_observer],
metrics=actor.collect_metrics(buffer_size=10) + [collect_env_step_metric],
reference_metrics=[collect_env_step_metric],
summary_dir=os.path.join(root_dir, learner.TRAIN_DIR),
summary_interval=summary_interval)
eval_greedy_policy = py_tf_eager_policy.PyTFEagerPolicy(
agent.policy, use_tf_function=True)
if eval_interval:
logging.info('Intial evaluation.')
eval_actor = actor.Actor(
eval_env,
eval_greedy_policy,
train_step,
metrics=actor.eval_metrics(eval_episodes),
reference_metrics=[collect_env_step_metric],
summary_dir=os.path.join(root_dir, 'eval'),
episodes_per_run=eval_episodes)
eval_actor.run_and_log()
logging.info('Training on %s', env_name)
last_eval_step = 0
for i in range(num_iterations):
collect_actor.run()
rb_observer.flush()
agent_learner.run()
reverb_replay_train.clear()
reverb_replay_normalization.clear()
current_iteration.assign_add(1)
# Eval only if `eval_interval` has been set. Then, eval if the current train
# step is equal or greater than the `last_eval_step` + `eval_interval` or if
# this is the last iteration. This logic exists because agent_learner.run()
# does not return after every train step.
if (eval_interval and
(agent_learner.train_step_numpy >= eval_interval + last_eval_step
or i == num_iterations - 1)):
logging.info('Evaluating.')
eval_actor.run_and_log()
last_eval_step = agent_learner.train_step_numpy
rb_observer.close()
reverb_server.stop()
def _create_and_yield(client):
yield reverb_utils.ReverbTrajectorySequenceObserver(
client, *args, **kwargs)
def train_eval(
root_dir,
env_name,
# Training params
train_sequence_length,
initial_collect_steps=1000,
collect_steps_per_iteration=1,
num_iterations=100000,
# RNN params.
q_network_fn=q_lstm_network, # defaults to q_lstm_network.
# Agent params
epsilon_greedy=0.1,
batch_size=64,
learning_rate=1e-3,
gamma=0.99,
target_update_tau=0.05,
target_update_period=5,
reward_scale_factor=1.0,
# Replay params
reverb_port=None,
replay_capacity=100000,
# Others
policy_save_interval=1000,
eval_interval=1000,
eval_episodes=10):
"""Trains and evaluates DQN."""
collect_env = suite_gym.load(env_name)
eval_env = suite_gym.load(env_name)
unused_observation_tensor_spec, action_tensor_spec, time_step_tensor_spec = (
spec_utils.get_tensor_specs(collect_env))
train_step = train_utils.create_train_step()
num_actions = action_tensor_spec.maximum - action_tensor_spec.minimum + 1
q_net = q_network_fn(num_actions=num_actions)
sequence_length = train_sequence_length + 1
agent = dqn_agent.DqnAgent(
time_step_tensor_spec,
action_tensor_spec,
q_network=q_net,
epsilon_greedy=epsilon_greedy,
# n-step updates aren't supported with RNNs yet.
n_step_update=1,
target_update_tau=target_update_tau,
target_update_period=target_update_period,
optimizer=tf.compat.v1.train.AdamOptimizer(
learning_rate=learning_rate),
td_errors_loss_fn=common.element_wise_squared_loss,
gamma=gamma,
reward_scale_factor=reward_scale_factor,
train_step_counter=train_step)
table_name = 'uniform_table'
table = reverb.Table(table_name,
max_size=replay_capacity,
sampler=reverb.selectors.Uniform(),
remover=reverb.selectors.Fifo(),
rate_limiter=reverb.rate_limiters.MinSize(1))
reverb_server = reverb.Server([table], port=reverb_port)
reverb_replay = reverb_replay_buffer.ReverbReplayBuffer(
agent.collect_data_spec,
sequence_length=sequence_length,
table_name=table_name,
local_server=reverb_server)
rb_observer = reverb_utils.ReverbTrajectorySequenceObserver(
reverb_replay.py_client,
table_name,
sequence_length=sequence_length,
stride_length=1)
dataset = reverb_replay.as_dataset(num_parallel_calls=3,
sample_batch_size=batch_size,
num_steps=sequence_length).prefetch(3)
experience_dataset_fn = lambda: dataset
saved_model_dir = os.path.join(root_dir, learner.POLICY_SAVED_MODEL_DIR)
env_step_metric = py_metrics.EnvironmentSteps()
learning_triggers = [
triggers.PolicySavedModelTrigger(
saved_model_dir,
agent,
train_step,
interval=policy_save_interval,
metadata_metrics={triggers.ENV_STEP_METADATA_KEY:
env_step_metric}),
triggers.StepPerSecondLogTrigger(train_step, interval=100),
]
dqn_learner = learner.Learner(root_dir,
train_step,
agent,
experience_dataset_fn,
triggers=learning_triggers)
# If we haven't trained yet make sure we collect some random samples first to
# fill up the Replay Buffer with some experience.
random_policy = random_py_policy.RandomPyPolicy(
collect_env.time_step_spec(), collect_env.action_spec())
initial_collect_actor = actor.Actor(collect_env,
random_policy,
train_step,
steps_per_run=initial_collect_steps,
observers=[rb_observer])
logging.info('Doing initial collect.')
initial_collect_actor.run()
tf_collect_policy = agent.collect_policy
collect_policy = py_tf_eager_policy.PyTFEagerPolicy(tf_collect_policy,
use_tf_function=True)
collect_actor = actor.Actor(
collect_env,
collect_policy,
train_step,
steps_per_run=collect_steps_per_iteration,
observers=[rb_observer, env_step_metric],
metrics=actor.collect_metrics(10),
summary_dir=os.path.join(root_dir, learner.TRAIN_DIR),
)
tf_greedy_policy = agent.policy
greedy_policy = py_tf_eager_policy.PyTFEagerPolicy(tf_greedy_policy,
use_tf_function=True)
eval_actor = actor.Actor(
eval_env,
greedy_policy,
train_step,
episodes_per_run=eval_episodes,
metrics=actor.eval_metrics(eval_episodes),
summary_dir=os.path.join(root_dir, 'eval'),
)
if eval_interval:
logging.info('Evaluating.')
eval_actor.run_and_log()
logging.info('Training.')
for _ in range(num_iterations):
collect_actor.run()
dqn_learner.run(iterations=1)
if eval_interval and dqn_learner.train_step_numpy % eval_interval == 0:
logging.info('Evaluating.')
eval_actor.run_and_log()
rb_observer.close()
reverb_server.stop()
