206 lines
7.9 KiB
Python
206 lines
7.9 KiB
Python
import logging
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import math
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from typing import Dict
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import numpy as np
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from ray._common.deprecation import deprecation_warning
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from ray.rllib.policy.sample_batch import DEFAULT_POLICY_ID
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from ray.rllib.utils.annotations import OldAPIStack
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from ray.rllib.utils.framework import try_import_tf
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from ray.rllib.utils.metrics import (
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LEARN_ON_BATCH_TIMER,
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LOAD_BATCH_TIMER,
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NUM_AGENT_STEPS_TRAINED,
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NUM_ENV_STEPS_TRAINED,
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)
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from ray.rllib.utils.metrics.learner_info import LearnerInfoBuilder
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from ray.rllib.utils.sgd import do_minibatch_sgd
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from ray.util import log_once
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tf1, tf, tfv = try_import_tf()
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logger = logging.getLogger(__name__)
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@OldAPIStack
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def train_one_step(algorithm, train_batch, policies_to_train=None) -> Dict:
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"""Function that improves the all policies in `train_batch` on the local worker.
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.. testcode::
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:skipif: True
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from ray.rllib.execution.rollout_ops import synchronous_parallel_sample
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algo = [...]
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train_batch = synchronous_parallel_sample(algo.env_runner_group)
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# This trains the policy on one batch.
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print(train_one_step(algo, train_batch)))
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.. testoutput::
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{"default_policy": ...}
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Updates the NUM_ENV_STEPS_TRAINED and NUM_AGENT_STEPS_TRAINED counters as well as
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the LEARN_ON_BATCH_TIMER timer of the `algorithm` object.
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"""
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config = algorithm.config
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workers = algorithm.env_runner_group
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local_worker = workers.local_env_runner
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num_sgd_iter = config.get("num_epochs", config.get("num_sgd_iter", 1))
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minibatch_size = config.get("minibatch_size")
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if minibatch_size is None:
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minibatch_size = config.get("sgd_minibatch_size", 0)
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learn_timer = algorithm._timers[LEARN_ON_BATCH_TIMER]
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with learn_timer:
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# Subsample minibatches (size=`minibatch_size`) from the
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# train batch and loop through train batch `num_sgd_iter` times.
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if num_sgd_iter > 1 or minibatch_size > 0:
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info = do_minibatch_sgd(
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train_batch,
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{
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pid: local_worker.get_policy(pid)
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for pid in policies_to_train
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or local_worker.get_policies_to_train(train_batch)
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},
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local_worker,
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num_sgd_iter,
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minibatch_size,
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[],
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)
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# Single update step using train batch.
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else:
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info = local_worker.learn_on_batch(train_batch)
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learn_timer.push_units_processed(train_batch.count)
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algorithm._counters[NUM_ENV_STEPS_TRAINED] += train_batch.count
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algorithm._counters[NUM_AGENT_STEPS_TRAINED] += train_batch.agent_steps()
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if algorithm.reward_estimators:
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info[DEFAULT_POLICY_ID]["off_policy_estimation"] = {}
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for name, estimator in algorithm.reward_estimators.items():
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info[DEFAULT_POLICY_ID]["off_policy_estimation"][name] = estimator.train(
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train_batch
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)
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return info
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@OldAPIStack
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def multi_gpu_train_one_step(algorithm, train_batch) -> Dict:
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"""Multi-GPU version of train_one_step.
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Uses the policies' `load_batch_into_buffer` and `learn_on_loaded_batch` methods
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to be more efficient wrt CPU/GPU data transfers. For example, when doing multiple
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passes through a train batch (e.g. for PPO) using `config.num_sgd_iter`, the
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actual train batch is only split once and loaded once into the GPU(s).
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.. testcode::
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:skipif: True
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from ray.rllib.execution.rollout_ops import synchronous_parallel_sample
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algo = [...]
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train_batch = synchronous_parallel_sample(algo.env_runner_group)
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# This trains the policy on one batch.
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print(multi_gpu_train_one_step(algo, train_batch)))
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.. testoutput::
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{"default_policy": ...}
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Updates the NUM_ENV_STEPS_TRAINED and NUM_AGENT_STEPS_TRAINED counters as well as
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the LOAD_BATCH_TIMER and LEARN_ON_BATCH_TIMER timers of the Algorithm instance.
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"""
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if log_once("mulit_gpu_train_one_step_deprecation_warning"):
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deprecation_warning(
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old=("ray.rllib.execution.train_ops.multi_gpu_train_one_step")
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)
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config = algorithm.config
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workers = algorithm.env_runner_group
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local_worker = workers.local_env_runner
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num_sgd_iter = config.get("num_epochs", config.get("num_sgd_iter", 1))
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minibatch_size = config.get("minibatch_size")
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if minibatch_size is None:
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minibatch_size = config["train_batch_size"]
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# Determine the number of devices (GPUs or 1 CPU) we use.
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num_devices = int(math.ceil(config["num_gpus"] or 1))
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# Make sure total batch size is dividable by the number of devices.
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# Batch size per tower.
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per_device_batch_size = minibatch_size // num_devices
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# Total batch size.
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batch_size = per_device_batch_size * num_devices
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assert batch_size % num_devices == 0
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assert batch_size >= num_devices, "Batch size too small!"
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# Handle everything as if multi-agent.
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train_batch = train_batch.as_multi_agent()
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# Load data into GPUs.
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load_timer = algorithm._timers[LOAD_BATCH_TIMER]
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with load_timer:
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num_loaded_samples = {}
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for policy_id, batch in train_batch.policy_batches.items():
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# Not a policy-to-train.
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if (
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local_worker.is_policy_to_train is not None
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and not local_worker.is_policy_to_train(policy_id, train_batch)
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):
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continue
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# Decompress SampleBatch, in case some columns are compressed.
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batch.decompress_if_needed()
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# Load the entire train batch into the Policy's only buffer
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# (idx=0). Policies only have >1 buffers, if we are training
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# asynchronously.
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num_loaded_samples[policy_id] = local_worker.policy_map[
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policy_id
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].load_batch_into_buffer(batch, buffer_index=0)
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# Execute minibatch SGD on loaded data.
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learn_timer = algorithm._timers[LEARN_ON_BATCH_TIMER]
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with learn_timer:
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# Use LearnerInfoBuilder as a unified way to build the final
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# results dict from `learn_on_loaded_batch` call(s).
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# This makes sure results dicts always have the same structure
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# no matter the setup (multi-GPU, multi-agent, minibatch SGD,
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# tf vs torch).
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learner_info_builder = LearnerInfoBuilder(num_devices=num_devices)
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for policy_id, samples_per_device in num_loaded_samples.items():
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policy = local_worker.policy_map[policy_id]
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num_batches = max(1, int(samples_per_device) // int(per_device_batch_size))
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logger.debug("== sgd epochs for {} ==".format(policy_id))
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for _ in range(num_sgd_iter):
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permutation = np.random.permutation(num_batches)
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for batch_index in range(num_batches):
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# Learn on the pre-loaded data in the buffer.
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# Note: For minibatch SGD, the data is an offset into
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# the pre-loaded entire train batch.
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results = policy.learn_on_loaded_batch(
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permutation[batch_index] * per_device_batch_size, buffer_index=0
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)
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learner_info_builder.add_learn_on_batch_results(results, policy_id)
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# Tower reduce and finalize results.
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learner_info = learner_info_builder.finalize()
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load_timer.push_units_processed(train_batch.count)
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learn_timer.push_units_processed(train_batch.count)
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# TODO: Move this into Algorithm's `training_step` method for
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# better transparency.
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algorithm._counters[NUM_ENV_STEPS_TRAINED] += train_batch.count
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algorithm._counters[NUM_AGENT_STEPS_TRAINED] += train_batch.agent_steps()
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if algorithm.reward_estimators:
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learner_info[DEFAULT_POLICY_ID]["off_policy_estimation"] = {}
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for name, estimator in algorithm.reward_estimators.items():
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learner_info[DEFAULT_POLICY_ID]["off_policy_estimation"][
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name
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] = estimator.train(train_batch)
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return learner_info
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