mirror of
https://github.com/vale981/ray
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108 lines
3.7 KiB
Python
108 lines
3.7 KiB
Python
import logging
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from typing import Optional, Type
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from ray.rllib.agents.a3c.a3c_tf_policy import A3CTFPolicy
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from ray.rllib.agents.trainer import with_common_config
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from ray.rllib.agents.trainer_template import build_trainer
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from ray.rllib.execution.rollout_ops import AsyncGradients
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from ray.rllib.execution.train_ops import ApplyGradients
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from ray.rllib.execution.metric_ops import StandardMetricsReporting
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from ray.rllib.utils.typing import TrainerConfigDict
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from ray.rllib.evaluation.worker_set import WorkerSet
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from ray.util.iter import LocalIterator
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from ray.rllib.policy.policy import Policy
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logger = logging.getLogger(__name__)
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# yapf: disable
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# __sphinx_doc_begin__
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DEFAULT_CONFIG = with_common_config({
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# Should use a critic as a baseline (otherwise don't use value baseline;
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# required for using GAE).
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"use_critic": True,
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# If true, use the Generalized Advantage Estimator (GAE)
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# with a value function, see https://arxiv.org/pdf/1506.02438.pdf.
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"use_gae": True,
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# Size of rollout batch
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"rollout_fragment_length": 10,
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# GAE(gamma) parameter
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"lambda": 1.0,
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# Max global norm for each gradient calculated by worker
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"grad_clip": 40.0,
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# Learning rate
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"lr": 0.0001,
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# Learning rate schedule
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"lr_schedule": None,
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# Value Function Loss coefficient
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"vf_loss_coeff": 0.5,
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# Entropy coefficient
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"entropy_coeff": 0.01,
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# Min time per iteration
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"min_iter_time_s": 5,
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# Workers sample async. Note that this increases the effective
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# rollout_fragment_length by up to 5x due to async buffering of batches.
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"sample_async": True,
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})
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# __sphinx_doc_end__
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# yapf: enable
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def get_policy_class(config: TrainerConfigDict) -> Optional[Type[Policy]]:
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"""Policy class picker function. Class is chosen based on DL-framework.
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Args:
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config (TrainerConfigDict): The trainer's configuration dict.
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Returns:
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Optional[Type[Policy]]: The Policy class to use with DQNTrainer.
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If None, use `default_policy` provided in build_trainer().
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"""
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if config["framework"] == "torch":
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from ray.rllib.agents.a3c.a3c_torch_policy import \
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A3CTorchPolicy
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return A3CTorchPolicy
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else:
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return A3CTFPolicy
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def validate_config(config: TrainerConfigDict) -> None:
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"""Checks and updates the config based on settings.
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Rewrites rollout_fragment_length to take into account n_step truncation.
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"""
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if config["entropy_coeff"] < 0:
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raise ValueError("`entropy_coeff` must be >= 0.0!")
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if config["num_workers"] <= 0 and config["sample_async"]:
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raise ValueError("`num_workers` for A3C must be >= 1!")
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def execution_plan(workers: WorkerSet,
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config: TrainerConfigDict) -> LocalIterator[dict]:
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"""Execution plan of the MARWIL/BC algorithm. Defines the distributed
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dataflow.
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Args:
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workers (WorkerSet): The WorkerSet for training the Polic(y/ies)
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of the Trainer.
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config (TrainerConfigDict): The trainer's configuration dict.
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Returns:
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LocalIterator[dict]: A local iterator over training metrics.
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"""
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# For A3C, compute policy gradients remotely on the rollout workers.
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grads = AsyncGradients(workers)
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# Apply the gradients as they arrive. We set update_all to False so that
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# only the worker sending the gradient is updated with new weights.
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train_op = grads.for_each(ApplyGradients(workers, update_all=False))
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return StandardMetricsReporting(train_op, workers, config)
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A3CTrainer = build_trainer(
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name="A3C",
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default_config=DEFAULT_CONFIG,
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default_policy=A3CTFPolicy,
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get_policy_class=get_policy_class,
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validate_config=validate_config,
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execution_plan=execution_plan)
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