"""
Deep Q-Networks (DQN, Rainbow, Parametric DQN)
==============================================
This file defines the distributed Algorithm class for the Deep Q-Networks
algorithm. See `dqn_[tf|torch]_policy.py` for the definition of the policies.
Detailed documentation:
https://docs.ray.io/en/master/rllib-algorithms.html#deep-q-networks-dqn-rainbow-parametric-dqn
""" # noqa: E501
from collections import defaultdict
import logging
from typing import Any, Callable, Dict, List, Optional, Tuple, Type, Union
import numpy as np
from ray.rllib.algorithms.algorithm import Algorithm
from ray.rllib.algorithms.algorithm_config import AlgorithmConfig, NotProvided
from ray.rllib.algorithms.dqn.dqn_tf_policy import DQNTFPolicy
from ray.rllib.algorithms.dqn.dqn_torch_policy import DQNTorchPolicy
from ray.rllib.connectors.common.add_observations_from_episodes_to_batch import (
AddObservationsFromEpisodesToBatch,
)
from ray.rllib.connectors.learner.add_next_observations_from_episodes_to_train_batch import ( # noqa
AddNextObservationsFromEpisodesToTrainBatch,
)
from ray.rllib.core.learner import Learner
from ray.rllib.core.rl_module.rl_module import RLModuleSpec
from ray.rllib.execution.rollout_ops import (
synchronous_parallel_sample,
)
from ray.rllib.policy.sample_batch import MultiAgentBatch
from ray.rllib.execution.train_ops import (
train_one_step,
multi_gpu_train_one_step,
)
from ray.rllib.policy.policy import Policy
from ray.rllib.utils import deep_update
from ray.rllib.utils.annotations import override
from ray.rllib.utils.numpy import convert_to_numpy
from ray.rllib.utils.replay_buffers.utils import (
update_priorities_in_episode_replay_buffer,
update_priorities_in_replay_buffer,
validate_buffer_config,
)
from ray.rllib.utils.typing import ResultDict
from ray.rllib.utils.metrics import (
ALL_MODULES,
ENV_RUNNER_RESULTS,
ENV_RUNNER_SAMPLING_TIMER,
LAST_TARGET_UPDATE_TS,
LEARNER_RESULTS,
LEARNER_UPDATE_TIMER,
NUM_AGENT_STEPS_SAMPLED,
NUM_AGENT_STEPS_SAMPLED_LIFETIME,
NUM_ENV_STEPS_SAMPLED,
NUM_ENV_STEPS_SAMPLED_LIFETIME,
NUM_TARGET_UPDATES,
REPLAY_BUFFER_ADD_DATA_TIMER,
REPLAY_BUFFER_SAMPLE_TIMER,
REPLAY_BUFFER_UPDATE_PRIOS_TIMER,
SAMPLE_TIMER,
SYNCH_WORKER_WEIGHTS_TIMER,
TD_ERROR_KEY,
TIMERS,
)
from ray.rllib.utils.deprecation import DEPRECATED_VALUE
from ray.rllib.utils.replay_buffers.utils import sample_min_n_steps_from_buffer
from ray.rllib.utils.typing import (
LearningRateOrSchedule,
RLModuleSpecType,
SampleBatchType,
)
logger = logging.getLogger(__name__)
[docs]
class DQNConfig(AlgorithmConfig):
r"""Defines a configuration class from which a DQN Algorithm can be built.
.. testcode::
from ray.rllib.algorithms.dqn.dqn import DQNConfig
config = (
DQNConfig()
.environment("CartPole-v1")
.training(replay_buffer_config={
"type": "PrioritizedEpisodeReplayBuffer",
"capacity": 60000,
"alpha": 0.5,
"beta": 0.5,
})
.env_runners(num_env_runners=1)
)
algo = config.build()
algo.train()
algo.stop()
.. testcode::
from ray.rllib.algorithms.dqn.dqn import DQNConfig
from ray import air
from ray import tune
config = (
DQNConfig()
.environment("CartPole-v1")
.training(
num_atoms=tune.grid_search([1,])
)
)
tune.Tuner(
"DQN",
run_config=air.RunConfig(stop={"training_iteration":1}),
param_space=config,
).fit()
.. testoutput::
:hide:
...
"""
def __init__(self, algo_class=None):
"""Initializes a DQNConfig instance."""
self.exploration_config = {
"type": "EpsilonGreedy",
"initial_epsilon": 1.0,
"final_epsilon": 0.02,
"epsilon_timesteps": 10000,
}
super().__init__(algo_class=algo_class or DQN)
# Overrides of AlgorithmConfig defaults
# `env_runners()`
# Set to `self.n_step`, if 'auto'.
self.rollout_fragment_length: Union[int, str] = "auto"
# New stack uses `epsilon` as either a constant value or a scheduler
# defined like this.
# TODO (simon): Ensure that users can understand how to provide epsilon.
# (sven): Should we add this to `self.env_runners(epsilon=..)`?
self.epsilon = [(0, 1.0), (10000, 0.05)]
# `training()`
self.grad_clip = 40.0
# Note: Only when using enable_rl_module_and_learner=True can the clipping mode
# be configured by the user. On the old API stack, RLlib will always clip by
# global_norm, no matter the value of `grad_clip_by`.
self.grad_clip_by = "global_norm"
self.lr = 5e-4
self.train_batch_size = 32
# `evaluation()`
self.evaluation(evaluation_config=AlgorithmConfig.overrides(explore=False))
# `reporting()`
self.min_time_s_per_iteration = None
self.min_sample_timesteps_per_iteration = 1000
# DQN specific config settings.
# fmt: off
# __sphinx_doc_begin__
self.target_network_update_freq = 500
self.num_steps_sampled_before_learning_starts = 1000
self.store_buffer_in_checkpoints = False
self.adam_epsilon = 1e-8
self.tau = 1.0
self.num_atoms = 1
self.v_min = -10.0
self.v_max = 10.0
self.noisy = False
self.sigma0 = 0.5
self.dueling = True
self.hiddens = [256]
self.double_q = True
self.n_step = 1
self.before_learn_on_batch = None
self.training_intensity = None
self.td_error_loss_fn = "huber"
self.categorical_distribution_temperature = 1.0
# Replay buffer configuration.
self.replay_buffer_config = {
"type": "PrioritizedEpisodeReplayBuffer",
# Size of the replay buffer. Note that if async_updates is set,
# then each worker will have a replay buffer of this size.
"capacity": 50000,
"alpha": 0.6,
# Beta parameter for sampling from prioritized replay buffer.
"beta": 0.4,
}
# fmt: on
# __sphinx_doc_end__
self.lr_schedule = None # @OldAPIStack
# Deprecated
self.buffer_size = DEPRECATED_VALUE
self.prioritized_replay = DEPRECATED_VALUE
self.learning_starts = DEPRECATED_VALUE
self.replay_batch_size = DEPRECATED_VALUE
# Can not use DEPRECATED_VALUE here because -1 is a common config value
self.replay_sequence_length = None
self.prioritized_replay_alpha = DEPRECATED_VALUE
self.prioritized_replay_beta = DEPRECATED_VALUE
self.prioritized_replay_eps = DEPRECATED_VALUE
[docs]
@override(AlgorithmConfig)
def training(
self,
*,
target_network_update_freq: Optional[int] = NotProvided,
replay_buffer_config: Optional[dict] = NotProvided,
store_buffer_in_checkpoints: Optional[bool] = NotProvided,
lr_schedule: Optional[List[List[Union[int, float]]]] = NotProvided,
epsilon: Optional[LearningRateOrSchedule] = NotProvided,
adam_epsilon: Optional[float] = NotProvided,
grad_clip: Optional[int] = NotProvided,
num_steps_sampled_before_learning_starts: Optional[int] = NotProvided,
tau: Optional[float] = NotProvided,
num_atoms: Optional[int] = NotProvided,
v_min: Optional[float] = NotProvided,
v_max: Optional[float] = NotProvided,
noisy: Optional[bool] = NotProvided,
sigma0: Optional[float] = NotProvided,
dueling: Optional[bool] = NotProvided,
hiddens: Optional[int] = NotProvided,
double_q: Optional[bool] = NotProvided,
n_step: Optional[Union[int, Tuple[int, int]]] = NotProvided,
before_learn_on_batch: Callable[
[Type[MultiAgentBatch], List[Type[Policy]], Type[int]],
Type[MultiAgentBatch],
] = NotProvided,
training_intensity: Optional[float] = NotProvided,
td_error_loss_fn: Optional[str] = NotProvided,
categorical_distribution_temperature: Optional[float] = NotProvided,
**kwargs,
) -> "DQNConfig":
"""Sets the training related configuration.
Args:
target_network_update_freq: Update the target network every
`target_network_update_freq` sample steps.
replay_buffer_config: Replay buffer config.
Examples:
{
"_enable_replay_buffer_api": True,
"type": "MultiAgentReplayBuffer",
"capacity": 50000,
"replay_sequence_length": 1,
}
- OR -
{
"_enable_replay_buffer_api": True,
"type": "MultiAgentPrioritizedReplayBuffer",
"capacity": 50000,
"prioritized_replay_alpha": 0.6,
"prioritized_replay_beta": 0.4,
"prioritized_replay_eps": 1e-6,
"replay_sequence_length": 1,
}
- Where -
prioritized_replay_alpha: Alpha parameter controls the degree of
prioritization in the buffer. In other words, when a buffer sample has
a higher temporal-difference error, with how much more probability
should it drawn to use to update the parametrized Q-network. 0.0
corresponds to uniform probability. Setting much above 1.0 may quickly
result as the sampling distribution could become heavily “pointy” with
low entropy.
prioritized_replay_beta: Beta parameter controls the degree of
importance sampling which suppresses the influence of gradient updates
from samples that have higher probability of being sampled via alpha
parameter and the temporal-difference error.
prioritized_replay_eps: Epsilon parameter sets the baseline probability
for sampling so that when the temporal-difference error of a sample is
zero, there is still a chance of drawing the sample.
store_buffer_in_checkpoints: Set this to True, if you want the contents of
your buffer(s) to be stored in any saved checkpoints as well.
Warnings will be created if:
- This is True AND restoring from a checkpoint that contains no buffer
data.
- This is False AND restoring from a checkpoint that does contain
buffer data.
epsilon: Epsilon exploration schedule. In the format of [[timestep, value],
[timestep, value], ...]. A schedule must start from
timestep 0.
adam_epsilon: Adam optimizer's epsilon hyper parameter.
grad_clip: If not None, clip gradients during optimization at this value.
num_steps_sampled_before_learning_starts: Number of timesteps to collect
from rollout workers before we start sampling from replay buffers for
learning. Whether we count this in agent steps or environment steps
depends on config.multi_agent(count_steps_by=..).
tau: Update the target by \tau * policy + (1-\tau) * target_policy.
num_atoms: Number of atoms for representing the distribution of return.
When this is greater than 1, distributional Q-learning is used.
v_min: Minimum value estimation
v_max: Maximum value estimation
noisy: Whether to use noisy network to aid exploration. This adds parametric
noise to the model weights.
sigma0: Control the initial parameter noise for noisy nets.
dueling: Whether to use dueling DQN.
hiddens: Dense-layer setup for each the advantage branch and the value
branch
double_q: Whether to use double DQN.
n_step: N-step target updates. If >1, sars' tuples in trajectories will be
postprocessed to become sa[discounted sum of R][s t+n] tuples. An
integer will be interpreted as a fixed n-step value. If a tuple of 2
ints is provided here, the n-step value will be drawn for each sample(!)
in the train batch from a uniform distribution over the closed interval
defined by `[n_step[0], n_step[1]]`.
before_learn_on_batch: Callback to run before learning on a multi-agent
batch of experiences.
training_intensity: The intensity with which to update the model (vs
collecting samples from the env).
If None, uses "natural" values of:
`train_batch_size` / (`rollout_fragment_length` x `num_env_runners` x
`num_envs_per_env_runner`).
If not None, will make sure that the ratio between timesteps inserted
into and sampled from the buffer matches the given values.
Example:
training_intensity=1000.0
train_batch_size=250
rollout_fragment_length=1
num_env_runners=1 (or 0)
num_envs_per_env_runner=1
-> natural value = 250 / 1 = 250.0
-> will make sure that replay+train op will be executed 4x asoften as
rollout+insert op (4 * 250 = 1000).
See: rllib/algorithms/dqn/dqn.py::calculate_rr_weights for further
details.
td_error_loss_fn: "huber" or "mse". loss function for calculating TD error
when num_atoms is 1. Note that if num_atoms is > 1, this parameter
is simply ignored, and softmax cross entropy loss will be used.
categorical_distribution_temperature: Set the temperature parameter used
by Categorical action distribution. A valid temperature is in the range
of [0, 1]. Note that this mostly affects evaluation since TD error uses
argmax for return calculation.
Returns:
This updated AlgorithmConfig object.
"""
# Pass kwargs onto super's `training()` method.
super().training(**kwargs)
if target_network_update_freq is not NotProvided:
self.target_network_update_freq = target_network_update_freq
if replay_buffer_config is not NotProvided:
# Override entire `replay_buffer_config` if `type` key changes.
# Update, if `type` key remains the same or is not specified.
new_replay_buffer_config = deep_update(
{"replay_buffer_config": self.replay_buffer_config},
{"replay_buffer_config": replay_buffer_config},
False,
["replay_buffer_config"],
["replay_buffer_config"],
)
self.replay_buffer_config = new_replay_buffer_config["replay_buffer_config"]
if store_buffer_in_checkpoints is not NotProvided:
self.store_buffer_in_checkpoints = store_buffer_in_checkpoints
if lr_schedule is not NotProvided:
self.lr_schedule = lr_schedule
if epsilon is not NotProvided:
self.epsilon = epsilon
if adam_epsilon is not NotProvided:
self.adam_epsilon = adam_epsilon
if grad_clip is not NotProvided:
self.grad_clip = grad_clip
if num_steps_sampled_before_learning_starts is not NotProvided:
self.num_steps_sampled_before_learning_starts = (
num_steps_sampled_before_learning_starts
)
if tau is not NotProvided:
self.tau = tau
if num_atoms is not NotProvided:
self.num_atoms = num_atoms
if v_min is not NotProvided:
self.v_min = v_min
if v_max is not NotProvided:
self.v_max = v_max
if noisy is not NotProvided:
self.noisy = noisy
if sigma0 is not NotProvided:
self.sigma0 = sigma0
if dueling is not NotProvided:
self.dueling = dueling
if hiddens is not NotProvided:
self.hiddens = hiddens
if double_q is not NotProvided:
self.double_q = double_q
if n_step is not NotProvided:
self.n_step = n_step
if before_learn_on_batch is not NotProvided:
self.before_learn_on_batch = before_learn_on_batch
if training_intensity is not NotProvided:
self.training_intensity = training_intensity
if td_error_loss_fn is not NotProvided:
self.td_error_loss_fn = td_error_loss_fn
if categorical_distribution_temperature is not NotProvided:
self.categorical_distribution_temperature = (
categorical_distribution_temperature
)
return self
@override(AlgorithmConfig)
def validate(self) -> None:
# Call super's validation method.
super().validate()
# Warn about new API stack on by default.
if self.enable_rl_module_and_learner:
logger.warning(
f"You are running {self.algo_class.__name__} on the new API stack! "
"This is the new default behavior for this algorithm. If you don't "
"want to use the new API stack, set `config.api_stack("
"enable_rl_module_and_learner=False,"
"enable_env_runner_and_connector_v2=False)`. For a detailed migration "
"guide, see here: https://docs.ray.io/en/master/rllib/new-api-stack-migration-guide.html" # noqa
)
if (
not self.enable_rl_module_and_learner
and self.exploration_config["type"] == "ParameterNoise"
):
if self.batch_mode != "complete_episodes":
raise ValueError(
"ParameterNoise Exploration requires `batch_mode` to be "
"'complete_episodes'. Try setting `config.env_runners("
"batch_mode='complete_episodes')`."
)
if not self.enable_env_runner_and_connector_v2 and not self.in_evaluation:
validate_buffer_config(self)
if self.td_error_loss_fn not in ["huber", "mse"]:
raise ValueError("`td_error_loss_fn` must be 'huber' or 'mse'!")
# Check rollout_fragment_length to be compatible with n_step.
if (
not self.in_evaluation
and self.rollout_fragment_length != "auto"
and self.rollout_fragment_length < self.n_step
):
raise ValueError(
f"Your `rollout_fragment_length` ({self.rollout_fragment_length}) is "
f"smaller than `n_step` ({self.n_step})! "
"Try setting config.env_runners(rollout_fragment_length="
f"{self.n_step})."
)
# TODO (simon): Find a clean solution to deal with
# configuration configs when using the new API stack.
if (
not self.enable_rl_module_and_learner
and self.exploration_config["type"] == "ParameterNoise"
):
if self.batch_mode != "complete_episodes":
raise ValueError(
"ParameterNoise Exploration requires `batch_mode` to be "
"'complete_episodes'. Try setting `config.env_runners("
"batch_mode='complete_episodes')`."
)
if self.noisy:
raise ValueError(
"ParameterNoise Exploration and `noisy` network cannot be"
" used at the same time!"
)
# Validate that we use the corresponding `EpisodeReplayBuffer` when using
# episodes.
# TODO (sven, simon): Implement the multi-agent case for replay buffers.
from ray.rllib.utils.replay_buffers.episode_replay_buffer import (
EpisodeReplayBuffer,
)
if (
self.enable_env_runner_and_connector_v2
and not isinstance(self.replay_buffer_config["type"], str)
and not issubclass(self.replay_buffer_config["type"], EpisodeReplayBuffer)
):
raise ValueError(
"When using the new `EnvRunner API` the replay buffer must be of type "
"`EpisodeReplayBuffer`."
)
elif not self.enable_env_runner_and_connector_v2 and (
(
isinstance(self.replay_buffer_config["type"], str)
and "Episode" in self.replay_buffer_config["type"]
)
or issubclass(self.replay_buffer_config["type"], EpisodeReplayBuffer)
):
raise ValueError(
"When using the old API stack the replay buffer must not be of type "
"`EpisodeReplayBuffer`! We suggest you use the following config to run "
"DQN on the old API stack: `config.training(replay_buffer_config={"
"'type': 'MultiAgentPrioritizedReplayBuffer', "
"'prioritized_replay_alpha': [alpha], "
"'prioritized_replay_beta': [beta], "
"'prioritized_replay_eps': [eps], "
"})`."
)
@override(AlgorithmConfig)
def get_rollout_fragment_length(self, worker_index: int = 0) -> int:
if self.rollout_fragment_length == "auto":
return (
self.n_step[1]
if isinstance(self.n_step, (tuple, list))
else self.n_step
)
else:
return self.rollout_fragment_length
@override(AlgorithmConfig)
def get_default_rl_module_spec(self) -> RLModuleSpecType:
from ray.rllib.algorithms.dqn.dqn_rainbow_catalog import DQNRainbowCatalog
if self.framework_str == "torch":
from ray.rllib.algorithms.dqn.torch.dqn_rainbow_torch_rl_module import (
DQNRainbowTorchRLModule,
)
return RLModuleSpec(
module_class=DQNRainbowTorchRLModule,
catalog_class=DQNRainbowCatalog,
model_config=self.model_config,
)
else:
raise ValueError(
f"The framework {self.framework_str} is not supported! "
"Use `config.framework('torch')` instead."
)
@property
@override(AlgorithmConfig)
def _model_config_auto_includes(self) -> Dict[str, Any]:
return super()._model_config_auto_includes | {
"double_q": self.double_q,
"dueling": self.dueling,
"epsilon": self.epsilon,
"noisy": self.noisy,
"num_atoms": self.num_atoms,
"std_init": self.sigma0,
"v_max": self.v_max,
"v_min": self.v_min,
}
@override(AlgorithmConfig)
def get_default_learner_class(self) -> Union[Type["Learner"], str]:
if self.framework_str == "torch":
from ray.rllib.algorithms.dqn.torch.dqn_rainbow_torch_learner import (
DQNRainbowTorchLearner,
)
return DQNRainbowTorchLearner
else:
raise ValueError(
f"The framework {self.framework_str} is not supported! "
"Use `config.framework('torch')` instead."
)
@override(AlgorithmConfig)
def build_learner_connector(
self,
input_observation_space,
input_action_space,
device=None,
):
pipeline = super().build_learner_connector(
input_observation_space=input_observation_space,
input_action_space=input_action_space,
device=device,
)
# Prepend the "add-NEXT_OBS-from-episodes-to-train-batch" connector piece (right
# after the corresponding "add-OBS-..." default piece).
pipeline.insert_after(
AddObservationsFromEpisodesToBatch,
AddNextObservationsFromEpisodesToTrainBatch(),
)
return pipeline
def calculate_rr_weights(config: AlgorithmConfig) -> List[float]:
"""Calculate the round robin weights for the rollout and train steps"""
if not config.training_intensity:
return [1, 1]
# Calculate the "native ratio" as:
# [train-batch-size] / [size of env-rolled-out sampled data]
# This is to set freshly rollout-collected data in relation to
# the data we pull from the replay buffer (which also contains old
# samples).
native_ratio = config.total_train_batch_size / (
config.get_rollout_fragment_length()
* config.num_envs_per_env_runner
# Add one to workers because the local
# worker usually collects experiences as well, and we avoid division by zero.
* max(config.num_env_runners + 1, 1)
)
# Training intensity is specified in terms of
# (steps_replayed / steps_sampled), so adjust for the native ratio.
sample_and_train_weight = config.training_intensity / native_ratio
if sample_and_train_weight < 1:
return [int(np.round(1 / sample_and_train_weight)), 1]
else:
return [1, int(np.round(sample_and_train_weight))]
class DQN(Algorithm):
@classmethod
@override(Algorithm)
def get_default_config(cls) -> AlgorithmConfig:
return DQNConfig()
@classmethod
@override(Algorithm)
def get_default_policy_class(
cls, config: AlgorithmConfig
) -> Optional[Type[Policy]]:
if config["framework"] == "torch":
return DQNTorchPolicy
else:
return DQNTFPolicy
@override(Algorithm)
def training_step(self) -> None:
"""DQN training iteration function.
Each training iteration, we:
- Sample (MultiAgentBatch) from workers.
- Store new samples in replay buffer.
- Sample training batch (MultiAgentBatch) from replay buffer.
- Learn on training batch.
- Update remote workers' new policy weights.
- Update target network every `target_network_update_freq` sample steps.
- Return all collected metrics for the iteration.
Returns:
The results dict from executing the training iteration.
"""
# Old API stack (Policy, RolloutWorker, Connector).
if not self.config.enable_env_runner_and_connector_v2:
return self._training_step_old_api_stack()
# New API stack (RLModule, Learner, EnvRunner, ConnectorV2).
return self._training_step_new_api_stack(with_noise_reset=True)
def _training_step_new_api_stack(self, *, with_noise_reset):
# Alternate between storing and sampling and training.
store_weight, sample_and_train_weight = calculate_rr_weights(self.config)
# Run multiple sampling + storing to buffer iterations.
for _ in range(store_weight):
with self.metrics.log_time((TIMERS, ENV_RUNNER_SAMPLING_TIMER)):
# Sample in parallel from workers.
episodes, env_runner_results = synchronous_parallel_sample(
worker_set=self.env_runner_group,
concat=True,
sample_timeout_s=self.config.sample_timeout_s,
_uses_new_env_runners=True,
_return_metrics=True,
)
# Reduce EnvRunner metrics over the n EnvRunners.
self.metrics.merge_and_log_n_dicts(
env_runner_results, key=ENV_RUNNER_RESULTS
)
# Add the sampled experiences to the replay buffer.
with self.metrics.log_time((TIMERS, REPLAY_BUFFER_ADD_DATA_TIMER)):
self.local_replay_buffer.add(episodes)
if self.config.count_steps_by == "agent_steps":
current_ts = sum(
self.metrics.peek(
(ENV_RUNNER_RESULTS, NUM_AGENT_STEPS_SAMPLED_LIFETIME), default={}
).values()
)
else:
current_ts = self.metrics.peek(
(ENV_RUNNER_RESULTS, NUM_ENV_STEPS_SAMPLED_LIFETIME), default=0
)
# If enough experiences have been sampled start training.
if current_ts >= self.config.num_steps_sampled_before_learning_starts:
# Resample noise for noisy networks, if necessary. Note, this
# is proposed in the "Noisy Networks for Exploration" paper
# (https://arxiv.org/abs/1706.10295) in Algorithm 1. The noise
# gets sampled once for each training loop.
if with_noise_reset:
self.learner_group.foreach_learner(
func=lambda lrnr: lrnr._reset_noise(),
timeout_seconds=0.0, # fire-and-forget
)
# Run multiple sample-from-buffer and update iterations.
for _ in range(sample_and_train_weight):
# Sample a list of episodes used for learning from the replay buffer.
with self.metrics.log_time((TIMERS, REPLAY_BUFFER_SAMPLE_TIMER)):
episodes = self.local_replay_buffer.sample(
num_items=self.config.total_train_batch_size,
n_step=self.config.n_step,
gamma=self.config.gamma,
beta=self.config.replay_buffer_config.get("beta"),
sample_episodes=True,
)
# Perform an update on the buffer-sampled train batch.
with self.metrics.log_time((TIMERS, LEARNER_UPDATE_TIMER)):
learner_results = self.learner_group.update_from_episodes(
episodes=episodes,
timesteps={
NUM_ENV_STEPS_SAMPLED_LIFETIME: (
self.metrics.peek(
(ENV_RUNNER_RESULTS, NUM_ENV_STEPS_SAMPLED_LIFETIME)
)
),
NUM_AGENT_STEPS_SAMPLED_LIFETIME: (
self.metrics.peek(
(
ENV_RUNNER_RESULTS,
NUM_AGENT_STEPS_SAMPLED_LIFETIME,
)
)
),
},
)
# Isolate TD-errors from result dicts (we should not log these to
# disk or WandB, they might be very large).
td_errors = defaultdict(list)
for res in learner_results:
for module_id, module_results in res.items():
if TD_ERROR_KEY in module_results:
td_errors[module_id].extend(
convert_to_numpy(
module_results.pop(TD_ERROR_KEY).peek()
)
)
td_errors = {
module_id: {TD_ERROR_KEY: np.concatenate(s, axis=0)}
for module_id, s in td_errors.items()
}
self.metrics.merge_and_log_n_dicts(
learner_results, key=LEARNER_RESULTS
)
# Update replay buffer priorities.
with self.metrics.log_time((TIMERS, REPLAY_BUFFER_UPDATE_PRIOS_TIMER)):
update_priorities_in_episode_replay_buffer(
replay_buffer=self.local_replay_buffer,
td_errors=td_errors,
)
# Update weights and global_vars - after learning on the local worker -
# on all remote workers.
with self.metrics.log_time((TIMERS, SYNCH_WORKER_WEIGHTS_TIMER)):
modules_to_update = set(learner_results[0].keys()) - {ALL_MODULES}
# NOTE: the new API stack does not use global vars.
self.env_runner_group.sync_weights(
from_worker_or_learner_group=self.learner_group,
policies=modules_to_update,
global_vars=None,
inference_only=True,
)
def _training_step_old_api_stack(self) -> ResultDict:
"""Training step for the old API stack.
More specifically this training step relies on `RolloutWorker`.
"""
train_results = {}
# We alternate between storing new samples and sampling and training
store_weight, sample_and_train_weight = calculate_rr_weights(self.config)
for _ in range(store_weight):
# Sample (MultiAgentBatch) from workers.
with self._timers[SAMPLE_TIMER]:
new_sample_batch: SampleBatchType = synchronous_parallel_sample(
worker_set=self.env_runner_group,
concat=True,
sample_timeout_s=self.config.sample_timeout_s,
)
# Return early if all our workers failed.
if not new_sample_batch:
return {}
# Update counters
self._counters[NUM_AGENT_STEPS_SAMPLED] += new_sample_batch.agent_steps()
self._counters[NUM_ENV_STEPS_SAMPLED] += new_sample_batch.env_steps()
# Store new samples in replay buffer.
self.local_replay_buffer.add(new_sample_batch)
global_vars = {
"timestep": self._counters[NUM_ENV_STEPS_SAMPLED],
}
# Update target network every `target_network_update_freq` sample steps.
cur_ts = self._counters[
(
NUM_AGENT_STEPS_SAMPLED
if self.config.count_steps_by == "agent_steps"
else NUM_ENV_STEPS_SAMPLED
)
]
if cur_ts > self.config.num_steps_sampled_before_learning_starts:
for _ in range(sample_and_train_weight):
# Sample training batch (MultiAgentBatch) from replay buffer.
train_batch = sample_min_n_steps_from_buffer(
self.local_replay_buffer,
self.config.total_train_batch_size,
count_by_agent_steps=self.config.count_steps_by == "agent_steps",
)
# Postprocess batch before we learn on it
post_fn = self.config.get("before_learn_on_batch") or (lambda b, *a: b)
train_batch = post_fn(train_batch, self.env_runner_group, self.config)
# Learn on training batch.
# Use simple optimizer (only for multi-agent or tf-eager; all other
# cases should use the multi-GPU optimizer, even if only using 1 GPU)
if self.config.get("simple_optimizer") is True:
train_results = train_one_step(self, train_batch)
else:
train_results = multi_gpu_train_one_step(self, train_batch)
# Update replay buffer priorities.
update_priorities_in_replay_buffer(
self.local_replay_buffer,
self.config,
train_batch,
train_results,
)
last_update = self._counters[LAST_TARGET_UPDATE_TS]
if cur_ts - last_update >= self.config.target_network_update_freq:
to_update = self.env_runner.get_policies_to_train()
self.env_runner.foreach_policy_to_train(
lambda p, pid, to_update=to_update: (
pid in to_update and p.update_target()
)
)
self._counters[NUM_TARGET_UPDATES] += 1
self._counters[LAST_TARGET_UPDATE_TS] = cur_ts
# Update weights and global_vars - after learning on the local worker -
# on all remote workers.
with self._timers[SYNCH_WORKER_WEIGHTS_TIMER]:
self.env_runner_group.sync_weights(global_vars=global_vars)
# Return all collected metrics for the iteration.
return train_results