Source code for ray.rllib.policy.torch_policy_v2

import copy
import functools
import logging
import math
import os
import threading
import time
from typing import TYPE_CHECKING, Any, Dict, List, Optional, Set, Tuple, Type, Union

import gymnasium as gym
import numpy as np
import tree  # pip install dm_tree

import ray
from ray.rllib.core.models.base import STATE_IN, STATE_OUT
from ray.rllib.core.rl_module import RLModule
from ray.rllib.models.catalog import ModelCatalog
from ray.rllib.models.modelv2 import ModelV2
from ray.rllib.models.torch.torch_action_dist import TorchDistributionWrapper
from ray.rllib.models.torch.torch_modelv2 import TorchModelV2
from ray.rllib.policy.policy import Policy
from ray.rllib.policy.rnn_sequencing import pad_batch_to_sequences_of_same_size
from ray.rllib.policy.sample_batch import SampleBatch
from ray.rllib.policy.torch_policy import _directStepOptimizerSingleton
from ray.rllib.utils import NullContextManager, force_list
from ray.rllib.utils.annotations import (
from ray.rllib.utils.annotations import ExperimentalAPI
from ray.rllib.utils.error import ERR_MSG_TORCH_POLICY_CANNOT_SAVE_MODEL
from ray.rllib.utils.framework import try_import_torch
from ray.rllib.utils.metrics import (
from ray.rllib.utils.metrics.learner_info import LEARNER_STATS_KEY
from ray.rllib.utils.numpy import convert_to_numpy
from ray.rllib.utils.spaces.space_utils import normalize_action
from ray.rllib.utils.threading import with_lock
from ray.rllib.utils.torch_utils import convert_to_torch_tensor
from ray.rllib.utils.typing import (

    from ray.rllib.evaluation import Episode  # noqa

torch, nn = try_import_torch()

logger = logging.getLogger(__name__)

[docs]@DeveloperAPI class TorchPolicyV2(Policy): """PyTorch specific Policy class to use with RLlib."""
[docs] @DeveloperAPI def __init__( self, observation_space: gym.spaces.Space, action_space: gym.spaces.Space, config: AlgorithmConfigDict, *, max_seq_len: int = 20, ): """Initializes a TorchPolicy instance. Args: observation_space: Observation space of the policy. action_space: Action space of the policy. config: The Policy's config dict. max_seq_len: Max sequence length for LSTM training. """ self.framework = config["framework"] = "torch" self._loss_initialized = False super().__init__(observation_space, action_space, config) # Create model. if self.config.get("_enable_rl_module_api", False): model = self.make_rl_module() dist_class = None else: model, dist_class = self._init_model_and_dist_class() # Create multi-GPU model towers, if necessary. # - The central main model will be stored under self.model, residing # on self.device (normally, a CPU). # - Each GPU will have a copy of that model under # self.model_gpu_towers, matching the devices in self.devices. # - Parallelization is done by splitting the train batch and passing # it through the model copies in parallel, then averaging over the # resulting gradients, applying these averages on the main model and # updating all towers' weights from the main model. # - In case of just one device (1 (fake or real) GPU or 1 CPU), no # parallelization will be done. # Get devices to build the graph on. num_gpus = self._get_num_gpus_for_policy() gpu_ids = list(range(torch.cuda.device_count()))"Found {len(gpu_ids)} visible cuda devices.") # Place on one or more CPU(s) when either: # - Fake GPU mode. # - num_gpus=0 (either set by user or we are in local_mode=True). # - No GPUs available. if config["_fake_gpus"] or num_gpus == 0 or not gpu_ids: self.device = torch.device("cpu") self.devices = [self.device for _ in range(int(math.ceil(num_gpus)) or 1)] self.model_gpu_towers = [ model if i == 0 else copy.deepcopy(model) for i in range(int(math.ceil(num_gpus)) or 1) ] if hasattr(self, "target_model"): self.target_models = { m: self.target_model for m in self.model_gpu_towers } self.model = model # Place on one or more actual GPU(s), when: # - num_gpus > 0 (set by user) AND # - local_mode=False AND # - actual GPUs available AND # - non-fake GPU mode. else: # We are a remote worker (WORKER_MODE=1): # GPUs should be assigned to us by ray. if ray._private.worker._mode() == ray._private.worker.WORKER_MODE: gpu_ids = ray.get_gpu_ids() if len(gpu_ids) < num_gpus: raise ValueError( "TorchPolicy was not able to find enough GPU IDs! Found " f"{gpu_ids}, but num_gpus={num_gpus}." ) self.devices = [ torch.device("cuda:{}".format(i)) for i, id_ in enumerate(gpu_ids) if i < num_gpus ] self.device = self.devices[0] ids = [id_ for i, id_ in enumerate(gpu_ids) if i < num_gpus] self.model_gpu_towers = [] for i, _ in enumerate(ids): model_copy = copy.deepcopy(model) self.model_gpu_towers.append([i])) if hasattr(self, "target_model"): self.target_models = { m: copy.deepcopy(self.target_model).to(self.devices[i]) for i, m in enumerate(self.model_gpu_towers) } self.model = self.model_gpu_towers[0] self.dist_class = dist_class self.unwrapped_model = model # used to support DistributedDataParallel # Lock used for locking some methods on the object-level. # This prevents possible race conditions when calling the model # first, then its value function (e.g. in a loss function), in # between of which another model call is made (e.g. to compute an # action). self._lock = threading.RLock() self._state_inputs = self.model.get_initial_state() self._is_recurrent = len(tree.flatten(self._state_inputs)) > 0 if self.config.get("_enable_rl_module_api", False): # Maybe update view_requirements, e.g. for recurrent case. self.view_requirements = self.model.update_default_view_requirements( self.view_requirements ) else: # Auto-update model's inference view requirements, if recurrent. self._update_model_view_requirements_from_init_state() # Combine view_requirements for Model and Policy. self.view_requirements.update(self.model.view_requirements) if self.config.get("_enable_rl_module_api", False): # We don't need an exploration object with RLModules self.exploration = None else: self.exploration = self._create_exploration() if not self.config.get("_enable_learner_api", False): self._optimizers = force_list(self.optimizer()) # Backward compatibility workaround so Policy will call self.loss() # directly. # TODO (jungong): clean up after all policies are migrated to new sub-class # implementation. self._loss = None # Store, which params (by index within the model's list of # parameters) should be updated per optimizer. # Maps optimizer idx to set or param indices. self.multi_gpu_param_groups: List[Set[int]] = [] main_params = {p: i for i, p in enumerate(self.model.parameters())} for o in self._optimizers: param_indices = [] for pg_idx, pg in enumerate(o.param_groups): for p in pg["params"]: param_indices.append(main_params[p]) self.multi_gpu_param_groups.append(set(param_indices)) # Create n sample-batch buffers (num_multi_gpu_tower_stacks), each # one with m towers (num_gpus). num_buffers = self.config.get("num_multi_gpu_tower_stacks", 1) self._loaded_batches = [[] for _ in range(num_buffers)] # If set, means we are using distributed allreduce during learning. self.distributed_world_size = None self.batch_divisibility_req = self.get_batch_divisibility_req() self.max_seq_len = max_seq_len # If model is an RLModule it won't have tower_stats instead there will be a # self.tower_state[model] -> dict for each tower. self.tower_stats = {} if not hasattr(self.model, "tower_stats"): for model in self.model_gpu_towers: self.tower_stats[model] = {}
def loss_initialized(self): return self._loss_initialized
[docs] @DeveloperAPI @OverrideToImplementCustomLogic @override(Policy) def loss( self, model: ModelV2, dist_class: Type[TorchDistributionWrapper], train_batch: SampleBatch, ) -> Union[TensorType, List[TensorType]]: """Constructs the loss function. Args: model: The Model to calculate the loss for. dist_class: The action distr. class. train_batch: The training data. Returns: Loss tensor given the input batch. """ # Under the new _enable_learner_api the loss function still gets called in order # to initialize the view requirements of the sample batches that are returned by # the sampler. In this case, we don't actually want to compute any loss, however # if we access the keys that are needed for a forward_train pass, then the # sampler will include those keys in the sample batches it returns. This means # that the correct sample batch keys will be available when using the learner # group API. if self.config._enable_learner_api: for k in model.input_specs_train(): train_batch[k] return None else: raise NotImplementedError
[docs] @DeveloperAPI @OverrideToImplementCustomLogic def action_sampler_fn( self, model: ModelV2, *, obs_batch: TensorType, state_batches: TensorType, **kwargs, ) -> Tuple[TensorType, TensorType, TensorType, List[TensorType]]: """Custom function for sampling new actions given policy. Args: model: Underlying model. obs_batch: Observation tensor batch. state_batches: Action sampling state batch. Returns: Sampled action Log-likelihood Action distribution inputs Updated state """ return None, None, None, None
[docs] @DeveloperAPI @OverrideToImplementCustomLogic def action_distribution_fn( self, model: ModelV2, *, obs_batch: TensorType, state_batches: TensorType, **kwargs, ) -> Tuple[TensorType, type, List[TensorType]]: """Action distribution function for this Policy. Args: model: Underlying model. obs_batch: Observation tensor batch. state_batches: Action sampling state batch. Returns: Distribution input. ActionDistribution class. State outs. """ return None, None, None
[docs] @DeveloperAPI @OverrideToImplementCustomLogic def make_model(self) -> ModelV2: """Create model. Note: only one of make_model or make_model_and_action_dist can be overridden. Returns: ModelV2 model. """ return None
@ExperimentalAPI @override(Policy) def maybe_remove_time_dimension(self, input_dict: Dict[str, TensorType]): assert self.config.get( "_enable_learner_api", False ), "This is a helper method for the new learner API." if self.config.get("_enable_rl_module_api", False) and self.model.is_stateful(): # Note that this is a temporary workaround to fit the old sampling stack # to RL Modules. ret = {} def fold_mapping(item): item = torch.as_tensor(item) size = item.size() b_dim, t_dim = list(size[:2]) other_dims = list(size[2:]) return item.reshape([b_dim * t_dim] + other_dims) for k, v in input_dict.items(): if k not in (STATE_IN, STATE_OUT): ret[k] = tree.map_structure(fold_mapping, v) else: # state in already has time dimension. ret[k] = v return ret else: return input_dict
[docs] @DeveloperAPI @OverrideToImplementCustomLogic def make_model_and_action_dist( self, ) -> Tuple[ModelV2, Type[TorchDistributionWrapper]]: """Create model and action distribution function. Returns: ModelV2 model. ActionDistribution class. """ return None, None
[docs] @DeveloperAPI @OverrideToImplementCustomLogic def get_batch_divisibility_req(self) -> int: """Get batch divisibility request. Returns: Size N. A sample batch must be of size K*N. """ # By default, any sized batch is ok, so simply return 1. return 1
[docs] @DeveloperAPI @OverrideToImplementCustomLogic def stats_fn(self, train_batch: SampleBatch) -> Dict[str, TensorType]: """Stats function. Returns a dict of statistics. Args: train_batch: The SampleBatch (already) used for training. Returns: The stats dict. """ return {}
[docs] @DeveloperAPI @OverrideToImplementCustomLogic_CallToSuperRecommended def extra_grad_process( self, optimizer: "torch.optim.Optimizer", loss: TensorType ) -> Dict[str, TensorType]: """Called after each optimizer.zero_grad() + loss.backward() call. Called for each self._optimizers/loss-value pair. Allows for gradient processing before optimizer.step() is called. E.g. for gradient clipping. Args: optimizer: A torch optimizer object. loss: The loss tensor associated with the optimizer. Returns: An dict with information on the gradient processing step. """ return {}
[docs] @DeveloperAPI @OverrideToImplementCustomLogic_CallToSuperRecommended def extra_compute_grad_fetches(self) -> Dict[str, Any]: """Extra values to fetch and return from compute_gradients(). Returns: Extra fetch dict to be added to the fetch dict of the `compute_gradients` call. """ return {LEARNER_STATS_KEY: {}} # e.g, stats, td error, etc.
[docs] @DeveloperAPI @OverrideToImplementCustomLogic_CallToSuperRecommended def extra_action_out( self, input_dict: Dict[str, TensorType], state_batches: List[TensorType], model: TorchModelV2, action_dist: TorchDistributionWrapper, ) -> Dict[str, TensorType]: """Returns dict of extra info to include in experience batch. Args: input_dict: Dict of model input tensors. state_batches: List of state tensors. model: Reference to the model object. action_dist: Torch action dist object to get log-probs (e.g. for already sampled actions). Returns: Extra outputs to return in a `compute_actions_from_input_dict()` call (3rd return value). """ return {}
[docs] @override(Policy) @DeveloperAPI @OverrideToImplementCustomLogic_CallToSuperRecommended def postprocess_trajectory( self, sample_batch: SampleBatch, other_agent_batches: Optional[Dict[Any, SampleBatch]] = None, episode: Optional["Episode"] = None, ) -> SampleBatch: """Postprocesses a trajectory and returns the processed trajectory. The trajectory contains only data from one episode and from one agent. - If `config.batch_mode=truncate_episodes` (default), sample_batch may contain a truncated (at-the-end) episode, in case the `config.rollout_fragment_length` was reached by the sampler. - If `config.batch_mode=complete_episodes`, sample_batch will contain exactly one episode (no matter how long). New columns can be added to sample_batch and existing ones may be altered. Args: sample_batch: The SampleBatch to postprocess. other_agent_batches (Optional[Dict[PolicyID, SampleBatch]]): Optional dict of AgentIDs mapping to other agents' trajectory data (from the same episode). NOTE: The other agents use the same policy. episode (Optional[Episode]): Optional multi-agent episode object in which the agents operated. Returns: SampleBatch: The postprocessed, modified SampleBatch (or a new one). """ return sample_batch
[docs] @DeveloperAPI @OverrideToImplementCustomLogic def optimizer( self, ) -> Union[List["torch.optim.Optimizer"], "torch.optim.Optimizer"]: """Custom the local PyTorch optimizer(s) to use. Returns: The local PyTorch optimizer(s) to use for this Policy. """ if hasattr(self, "config"): optimizers = [ torch.optim.Adam(self.model.parameters(), lr=self.config["lr"]) ] else: optimizers = [torch.optim.Adam(self.model.parameters())] if self.exploration: optimizers = self.exploration.get_exploration_optimizer(optimizers) return optimizers
def _init_model_and_dist_class(self): if is_overridden(self.make_model) and is_overridden( self.make_model_and_action_dist ): raise ValueError( "Only one of make_model or make_model_and_action_dist " "can be overridden." ) if is_overridden(self.make_model): model = self.make_model() dist_class, _ = ModelCatalog.get_action_dist( self.action_space, self.config["model"], framework=self.framework ) elif is_overridden(self.make_model_and_action_dist): model, dist_class = self.make_model_and_action_dist() else: dist_class, logit_dim = ModelCatalog.get_action_dist( self.action_space, self.config["model"], framework=self.framework ) model = ModelCatalog.get_model_v2( obs_space=self.observation_space, action_space=self.action_space, num_outputs=logit_dim, model_config=self.config["model"], framework=self.framework, ) return model, dist_class @override(Policy) def compute_actions_from_input_dict( self, input_dict: Dict[str, TensorType], explore: bool = None, timestep: Optional[int] = None, **kwargs, ) -> Tuple[TensorType, List[TensorType], Dict[str, TensorType]]: seq_lens = None with torch.no_grad(): # Pass lazy (torch) tensor dict to Model as `input_dict`. input_dict = self._lazy_tensor_dict(input_dict) input_dict.set_training(True) if self.config.get("_enable_rl_module_api", False): return self._compute_action_helper( input_dict, state_batches=None, seq_lens=None, explore=explore, timestep=timestep, ) else: # Pack internal state inputs into (separate) list. state_batches = [ input_dict[k] for k in input_dict.keys() if "state_in" in k[:8] ] # Calculate RNN sequence lengths. if state_batches: seq_lens = torch.tensor( [1] * len(state_batches[0]), dtype=torch.long, device=state_batches[0].device, ) return self._compute_action_helper( input_dict, state_batches, seq_lens, explore, timestep ) @override(Policy) @DeveloperAPI def compute_actions( self, obs_batch: Union[List[TensorStructType], TensorStructType], state_batches: Optional[List[TensorType]] = None, prev_action_batch: Union[List[TensorStructType], TensorStructType] = None, prev_reward_batch: Union[List[TensorStructType], TensorStructType] = None, info_batch: Optional[Dict[str, list]] = None, episodes: Optional[List["Episode"]] = None, explore: Optional[bool] = None, timestep: Optional[int] = None, **kwargs, ) -> Tuple[TensorStructType, List[TensorType], Dict[str, TensorType]]: with torch.no_grad(): seq_lens = torch.ones(len(obs_batch), dtype=torch.int32) input_dict = self._lazy_tensor_dict( { SampleBatch.CUR_OBS: obs_batch, "is_training": False, } ) if prev_action_batch is not None: input_dict[SampleBatch.PREV_ACTIONS] = np.asarray(prev_action_batch) if prev_reward_batch is not None: input_dict[SampleBatch.PREV_REWARDS] = np.asarray(prev_reward_batch) state_batches = [ convert_to_torch_tensor(s, self.device) for s in (state_batches or []) ] return self._compute_action_helper( input_dict, state_batches, seq_lens, explore, timestep ) @with_lock @override(Policy) @DeveloperAPI def compute_log_likelihoods( self, actions: Union[List[TensorStructType], TensorStructType], obs_batch: Union[List[TensorStructType], TensorStructType], state_batches: Optional[List[TensorType]] = None, prev_action_batch: Optional[ Union[List[TensorStructType], TensorStructType] ] = None, prev_reward_batch: Optional[ Union[List[TensorStructType], TensorStructType] ] = None, actions_normalized: bool = True, in_training: bool = True, ) -> TensorType: if is_overridden(self.action_sampler_fn) and not is_overridden( self.action_distribution_fn ): raise ValueError( "Cannot compute log-prob/likelihood w/o an " "`action_distribution_fn` and a provided " "`action_sampler_fn`!" ) with torch.no_grad(): input_dict = self._lazy_tensor_dict( {SampleBatch.CUR_OBS: obs_batch, SampleBatch.ACTIONS: actions} ) if prev_action_batch is not None: input_dict[SampleBatch.PREV_ACTIONS] = prev_action_batch if prev_reward_batch is not None: input_dict[SampleBatch.PREV_REWARDS] = prev_reward_batch seq_lens = torch.ones(len(obs_batch), dtype=torch.int32) state_batches = [ convert_to_torch_tensor(s, self.device) for s in (state_batches or []) ] if self.exploration: # Exploration hook before each forward pass. self.exploration.before_compute_actions(explore=False) # Action dist class and inputs are generated via custom function. if is_overridden(self.action_distribution_fn): dist_inputs, dist_class, state_out = self.action_distribution_fn( self.model, obs_batch=input_dict, state_batches=state_batches, seq_lens=seq_lens, explore=False, is_training=False, ) action_dist = dist_class(dist_inputs, self.model) # Default action-dist inputs calculation. else: if self.config.get("_enable_rl_module_api", False): if in_training: output = self.model.forward_train(input_dict) action_dist_cls = self.model.get_train_action_dist_cls() if action_dist_cls is None: raise ValueError( "The RLModules must provide an appropriate action " "distribution class for training if is_eval_mode is " "False." ) else: output = self.model.forward_exploration(input_dict) action_dist_cls = self.model.get_exploration_action_dist_cls() if action_dist_cls is None: raise ValueError( "The RLModules must provide an appropriate action " "distribution class for exploration if is_eval_mode is " "True." ) action_dist_inputs = output.get( SampleBatch.ACTION_DIST_INPUTS, None ) if action_dist_inputs is None: raise ValueError( "The RLModules must provide inputs to create the action " "distribution. These should be part of the output of the " "appropriate forward method under the key " "SampleBatch.ACTION_DIST_INPUTS." ) action_dist = action_dist_cls.from_logits(action_dist_inputs) else: dist_class = self.dist_class dist_inputs, _ = self.model(input_dict, state_batches, seq_lens) action_dist = dist_class(dist_inputs, self.model) # Normalize actions if necessary. actions = input_dict[SampleBatch.ACTIONS] if not actions_normalized and self.config["normalize_actions"]: actions = normalize_action(actions, self.action_space_struct) log_likelihoods = action_dist.logp(actions) return log_likelihoods @with_lock @override(Policy) @DeveloperAPI def learn_on_batch(self, postprocessed_batch: SampleBatch) -> Dict[str, TensorType]: # Set Model to train mode. if self.model: self.model.train() # Callback handling. learn_stats = {} self.callbacks.on_learn_on_batch( policy=self, train_batch=postprocessed_batch, result=learn_stats ) # Compute gradients (will calculate all losses and `backward()` # them to get the grads). grads, fetches = self.compute_gradients(postprocessed_batch) # Step the optimizers. self.apply_gradients(_directStepOptimizerSingleton) self.num_grad_updates += 1 if self.model and hasattr(self.model, "metrics"): fetches["model"] = self.model.metrics() else: fetches["model"] = {} fetches.update( { "custom_metrics": learn_stats, NUM_AGENT_STEPS_TRAINED: postprocessed_batch.count, NUM_GRAD_UPDATES_LIFETIME: self.num_grad_updates, # -1, b/c we have to measure this diff before we do the update above. DIFF_NUM_GRAD_UPDATES_VS_SAMPLER_POLICY: ( self.num_grad_updates - 1 - (postprocessed_batch.num_grad_updates or 0) ), } ) return fetches @override(Policy) @DeveloperAPI def load_batch_into_buffer( self, batch: SampleBatch, buffer_index: int = 0, ) -> int: # Set the is_training flag of the batch. batch.set_training(True) # Shortcut for 1 CPU only: Store batch in `self._loaded_batches`. if len(self.devices) == 1 and self.devices[0].type == "cpu": assert buffer_index == 0 pad_batch_to_sequences_of_same_size( batch=batch, max_seq_len=self.max_seq_len, shuffle=False, batch_divisibility_req=self.batch_divisibility_req, view_requirements=self.view_requirements, _enable_rl_module_api=self.config.get("_enable_rl_module_api", False), padding="last" if self.config.get("_enable_rl_module_api", False) else "zero", ) self._lazy_tensor_dict(batch) self._loaded_batches[0] = [batch] return len(batch) # Batch (len=28, seq-lens=[4, 7, 4, 10, 3]): # 0123 0123456 0123 0123456789ABC # 1) split into n per-GPU sub batches (n=2). # [0123 0123456] [012] [3 0123456789 ABC] # (len=14, 14 seq-lens=[4, 7, 3] [1, 10, 3]) slices = batch.timeslices(num_slices=len(self.devices)) # 2) zero-padding (max-seq-len=10). # - [0123000000 0123456000 0120000000] # - [3000000000 0123456789 ABC0000000] for slice in slices: pad_batch_to_sequences_of_same_size( batch=slice, max_seq_len=self.max_seq_len, shuffle=False, batch_divisibility_req=self.batch_divisibility_req, view_requirements=self.view_requirements, _enable_rl_module_api=self.config.get("_enable_rl_module_api", False), padding="last" if self.config.get("_enable_rl_module_api", False) else "zero", ) # 3) Load splits into the given buffer (consisting of n GPUs). slices = [slice.to_device(self.devices[i]) for i, slice in enumerate(slices)] self._loaded_batches[buffer_index] = slices # Return loaded samples per-device. return len(slices[0]) @override(Policy) @DeveloperAPI def get_num_samples_loaded_into_buffer(self, buffer_index: int = 0) -> int: if len(self.devices) == 1 and self.devices[0] == "/cpu:0": assert buffer_index == 0 return sum(len(b) for b in self._loaded_batches[buffer_index]) @override(Policy) @DeveloperAPI def learn_on_loaded_batch(self, offset: int = 0, buffer_index: int = 0): if not self._loaded_batches[buffer_index]: raise ValueError( "Must call Policy.load_batch_into_buffer() before " "Policy.learn_on_loaded_batch()!" ) # Get the correct slice of the already loaded batch to use, # based on offset and batch size. device_batch_size = self.config.get( "sgd_minibatch_size", self.config["train_batch_size"] ) // len(self.devices) # Set Model to train mode. if self.model_gpu_towers: for t in self.model_gpu_towers: t.train() # Shortcut for 1 CPU only: Batch should already be stored in # `self._loaded_batches`. if len(self.devices) == 1 and self.devices[0].type == "cpu": assert buffer_index == 0 if device_batch_size >= len(self._loaded_batches[0][0]): batch = self._loaded_batches[0][0] else: batch = self._loaded_batches[0][0][offset : offset + device_batch_size] return self.learn_on_batch(batch) if len(self.devices) > 1: # Copy weights of main model (tower-0) to all other towers. state_dict = self.model.state_dict() # Just making sure tower-0 is really the same as self.model. assert self.model_gpu_towers[0] is self.model for tower in self.model_gpu_towers[1:]: tower.load_state_dict(state_dict) if device_batch_size >= sum(len(s) for s in self._loaded_batches[buffer_index]): device_batches = self._loaded_batches[buffer_index] else: device_batches = [ b[offset : offset + device_batch_size] for b in self._loaded_batches[buffer_index] ] # Callback handling. batch_fetches = {} for i, batch in enumerate(device_batches): custom_metrics = {} self.callbacks.on_learn_on_batch( policy=self, train_batch=batch, result=custom_metrics ) batch_fetches[f"tower_{i}"] = {"custom_metrics": custom_metrics} # Do the (maybe parallelized) gradient calculation step. tower_outputs = self._multi_gpu_parallel_grad_calc(device_batches) # Mean-reduce gradients over GPU-towers (do this on CPU: self.device). all_grads = [] for i in range(len(tower_outputs[0][0])): if tower_outputs[0][0][i] is not None: all_grads.append( torch.mean( torch.stack([t[0][i].to(self.device) for t in tower_outputs]), dim=0, ) ) else: all_grads.append(None) # Set main model's grads to mean-reduced values. for i, p in enumerate(self.model.parameters()): p.grad = all_grads[i] self.apply_gradients(_directStepOptimizerSingleton) self.num_grad_updates += 1 for i, (model, batch) in enumerate(zip(self.model_gpu_towers, device_batches)): batch_fetches[f"tower_{i}"].update( { LEARNER_STATS_KEY: self.stats_fn(batch), "model": {} if self.config.get("_enable_rl_module_api", False) else model.metrics(), NUM_GRAD_UPDATES_LIFETIME: self.num_grad_updates, # -1, b/c we have to measure this diff before we do the update # above. DIFF_NUM_GRAD_UPDATES_VS_SAMPLER_POLICY: ( self.num_grad_updates - 1 - (batch.num_grad_updates or 0) ), } ) batch_fetches.update(self.extra_compute_grad_fetches()) return batch_fetches @with_lock @override(Policy) @DeveloperAPI def compute_gradients(self, postprocessed_batch: SampleBatch) -> ModelGradients: assert len(self.devices) == 1 # If not done yet, see whether we have to zero-pad this batch. if not postprocessed_batch.zero_padded: pad_batch_to_sequences_of_same_size( batch=postprocessed_batch, max_seq_len=self.max_seq_len, shuffle=False, batch_divisibility_req=self.batch_divisibility_req, view_requirements=self.view_requirements, _enable_rl_module_api=self.config.get("_enable_rl_module_api", False), padding="last" if self.config.get("_enable_rl_module_api", False) else "zero", ) postprocessed_batch.set_training(True) self._lazy_tensor_dict(postprocessed_batch, device=self.devices[0]) # Do the (maybe parallelized) gradient calculation step. tower_outputs = self._multi_gpu_parallel_grad_calc([postprocessed_batch]) all_grads, grad_info = tower_outputs[0] grad_info["allreduce_latency"] /= len(self._optimizers) grad_info.update(self.stats_fn(postprocessed_batch)) fetches = self.extra_compute_grad_fetches() return all_grads, dict(fetches, **{LEARNER_STATS_KEY: grad_info}) @override(Policy) @DeveloperAPI def apply_gradients(self, gradients: ModelGradients) -> None: if gradients == _directStepOptimizerSingleton: for i, opt in enumerate(self._optimizers): opt.step() else: # TODO(sven): Not supported for multiple optimizers yet. assert len(self._optimizers) == 1 for g, p in zip(gradients, self.model.parameters()): if g is not None: if torch.is_tensor(g): p.grad = else: p.grad = torch.from_numpy(g).to(self.device) self._optimizers[0].step()
[docs] @DeveloperAPI def get_tower_stats(self, stats_name: str) -> List[TensorStructType]: """Returns list of per-tower stats, copied to this Policy's device. Args: stats_name: The name of the stats to average over (this str must exist as a key inside each tower's `tower_stats` dict). Returns: The list of stats tensor (structs) of all towers, copied to this Policy's device. Raises: AssertionError: If the `stats_name` cannot be found in any one of the tower's `tower_stats` dicts. """ data = [] for model in self.model_gpu_towers: if self.tower_stats: tower_stats = self.tower_stats[model] else: tower_stats = model.tower_stats if stats_name in tower_stats: data.append( tree.map_structure( lambda s:, tower_stats[stats_name] ) ) assert len(data) > 0, ( f"Stats `{stats_name}` not found in any of the towers (you have " f"{len(self.model_gpu_towers)} towers in total)! Make " "sure you call the loss function on at least one of the towers." ) return data
@override(Policy) @DeveloperAPI def get_weights(self) -> ModelWeights: return {k: v.cpu().detach().numpy() for k, v in self.model.state_dict().items()} @override(Policy) @DeveloperAPI def set_weights(self, weights: ModelWeights) -> None: weights = convert_to_torch_tensor(weights, device=self.device) if self.config.get("_enable_rl_module_api", False): self.model.set_state(weights) else: self.model.load_state_dict(weights) @override(Policy) @DeveloperAPI def is_recurrent(self) -> bool: return self._is_recurrent @override(Policy) @DeveloperAPI def num_state_tensors(self) -> int: return len(self.model.get_initial_state()) @override(Policy) @DeveloperAPI def get_initial_state(self) -> List[TensorType]: if self.config.get("_enable_rl_module_api", False): # convert the tree of tensors to a tree to numpy arrays return tree.map_structure( lambda s: convert_to_numpy(s), self.model.get_initial_state() ) return [s.detach().cpu().numpy() for s in self.model.get_initial_state()] @override(Policy) @DeveloperAPI @OverrideToImplementCustomLogic_CallToSuperRecommended def get_state(self) -> PolicyState: # Legacy Policy state (w/o torch.nn.Module and w/o PolicySpec). state = super().get_state() state["_optimizer_variables"] = [] # In the new Learner API stack, the optimizers live in the learner. if not self.config.get("_enable_learner_api", False): for i, o in enumerate(self._optimizers): optim_state_dict = convert_to_numpy(o.state_dict()) state["_optimizer_variables"].append(optim_state_dict) # Add exploration state. if not self.config.get("_enable_rl_module_api", False) and self.exploration: # This is not compatible with RLModules, which have a method # `forward_exploration` to specify custom exploration behavior. state["_exploration_state"] = self.exploration.get_state() return state @override(Policy) @DeveloperAPI @OverrideToImplementCustomLogic_CallToSuperRecommended def set_state(self, state: PolicyState) -> None: # Set optimizer vars first. optimizer_vars = state.get("_optimizer_variables", None) if optimizer_vars: assert len(optimizer_vars) == len(self._optimizers) for o, s in zip(self._optimizers, optimizer_vars): # Torch optimizer param_groups include things like beta, etc. These # parameters should be left as scalar and not converted to tensors. # otherwise, torch.optim.step() will start to complain. optim_state_dict = {"param_groups": s["param_groups"]} optim_state_dict["state"] = convert_to_torch_tensor( s["state"], device=self.device ) o.load_state_dict(optim_state_dict) # Set exploration's state. if hasattr(self, "exploration") and "_exploration_state" in state: self.exploration.set_state(state=state["_exploration_state"]) # Restore glbal timestep. self.global_timestep = state["global_timestep"] # Then the Policy's (NN) weights and connectors. super().set_state(state)
[docs] @override(Policy) @DeveloperAPI def export_model(self, export_dir: str, onnx: Optional[int] = None) -> None: """Exports the Policy's Model to local directory for serving. Creates a TorchScript model and saves it. Args: export_dir: Local writable directory or filename. onnx: If given, will export model in ONNX format. The value of this parameter set the ONNX OpSet version to use. """ os.makedirs(export_dir, exist_ok=True) enable_rl_module = self.config.get("_enable_rl_module_api", False) if enable_rl_module and onnx: raise ValueError("ONNX export not supported for RLModule API.") if onnx: self._lazy_tensor_dict(self._dummy_batch) # Provide dummy state inputs if not an RNN (torch cannot jit with # returned empty internal states list). if "state_in_0" not in self._dummy_batch: self._dummy_batch["state_in_0"] = self._dummy_batch[ SampleBatch.SEQ_LENS ] = np.array([1.0]) seq_lens = self._dummy_batch[SampleBatch.SEQ_LENS] state_ins = [] i = 0 while "state_in_{}".format(i) in self._dummy_batch: state_ins.append(self._dummy_batch["state_in_{}".format(i)]) i += 1 dummy_inputs = { k: self._dummy_batch[k] for k in self._dummy_batch.keys() if k != "is_training" } file_name = os.path.join(export_dir, "model.onnx") torch.onnx.export( self.model, (dummy_inputs, state_ins, seq_lens), file_name, export_params=True, opset_version=onnx, do_constant_folding=True, input_names=list(dummy_inputs.keys()) + ["state_ins", SampleBatch.SEQ_LENS], output_names=["output", "state_outs"], dynamic_axes={ k: {0: "batch_size"} for k in list(dummy_inputs.keys()) + ["state_ins", SampleBatch.SEQ_LENS] }, ) # Save the torch.Model (architecture and weights, so it can be retrieved # w/o access to the original (custom) Model or Policy code). else: filename = os.path.join(export_dir, "") try:, f=filename) except Exception: if os.path.exists(filename): os.remove(filename) logger.warning(ERR_MSG_TORCH_POLICY_CANNOT_SAVE_MODEL)
[docs] @override(Policy) @DeveloperAPI def import_model_from_h5(self, import_file: str) -> None: """Imports weights into torch model.""" return self.model.import_from_h5(import_file)
@with_lock def _compute_action_helper( self, input_dict, state_batches, seq_lens, explore, timestep ): """Shared forward pass logic (w/ and w/o trajectory view API). Returns: A tuple consisting of a) actions, b) state_out, c) extra_fetches. The input_dict is modified in-place to include a numpy copy of the computed actions under `SampleBatch.ACTIONS`. """ explore = explore if explore is not None else self.config["explore"] timestep = timestep if timestep is not None else self.global_timestep # Switch to eval mode. if self.model: self.model.eval() extra_fetches = dist_inputs = logp = None # New API stack: `self.model` is-a RLModule. if isinstance(self.model, RLModule): if self.model.is_stateful(): # For recurrent models, we need to add a time dimension. if not seq_lens: # In order to calculate the batch size ad hoc, we need a sample # batch. if not isinstance(input_dict, SampleBatch): input_dict = SampleBatch(input_dict) seq_lens = np.array([1] * len(input_dict)) input_dict = self.maybe_add_time_dimension( input_dict, seq_lens=seq_lens ) input_dict = convert_to_torch_tensor(input_dict, device=self.device) # Batches going into the RL Module should not have seq_lens. if SampleBatch.SEQ_LENS in input_dict: del input_dict[SampleBatch.SEQ_LENS] if explore: fwd_out = self.model.forward_exploration(input_dict) # For recurrent models, we need to remove the time dimension. fwd_out = self.maybe_remove_time_dimension(fwd_out) # ACTION_DIST_INPUTS field returned by `forward_exploration()` -> # Create a distribution object. action_dist = None if SampleBatch.ACTION_DIST_INPUTS in fwd_out: dist_inputs = fwd_out[SampleBatch.ACTION_DIST_INPUTS] action_dist_class = self.model.get_exploration_action_dist_cls() action_dist = action_dist_class.from_logits(dist_inputs) # If `forward_exploration()` returned actions, use them here as-is. if SampleBatch.ACTIONS in fwd_out: actions = fwd_out[SampleBatch.ACTIONS] # Otherwise, sample actions from the distribution. else: if action_dist is None: raise KeyError( "Your RLModule's `forward_exploration()` method must return" f" a dict with either the {SampleBatch.ACTIONS} key or the " f"{SampleBatch.ACTION_DIST_INPUTS} key in it (or both)!" ) actions = action_dist.sample() # Compute action-logp and action-prob from distribution and add to # `extra_fetches`, if possible. if action_dist is not None: logp = action_dist.logp(actions) else: fwd_out = self.model.forward_inference(input_dict) # For recurrent models, we need to remove the time dimension. fwd_out = self.maybe_remove_time_dimension(fwd_out) # ACTION_DIST_INPUTS field returned by `forward_exploration()` -> # Create a distribution object. action_dist = None if SampleBatch.ACTION_DIST_INPUTS in fwd_out: dist_inputs = fwd_out[SampleBatch.ACTION_DIST_INPUTS] action_dist_class = self.model.get_inference_action_dist_cls() action_dist = action_dist_class.from_logits(dist_inputs) action_dist = action_dist.to_deterministic() # If `forward_inference()` returned actions, use them here as-is. if SampleBatch.ACTIONS in fwd_out: actions = fwd_out[SampleBatch.ACTIONS] # Otherwise, sample actions from the distribution. else: if action_dist is None: raise KeyError( "Your RLModule's `forward_inference()` method must return" f" a dict with either the {SampleBatch.ACTIONS} key or the " f"{SampleBatch.ACTION_DIST_INPUTS} key in it (or both)!" ) actions = action_dist.sample() # Anything but actions and state_out is an extra fetch. state_out = fwd_out.pop(STATE_OUT, {}) extra_fetches = fwd_out elif is_overridden(self.action_sampler_fn): action_dist = None actions, logp, dist_inputs, state_out = self.action_sampler_fn( self.model, obs_batch=input_dict, state_batches=state_batches, explore=explore, timestep=timestep, ) else: # Call the exploration before_compute_actions hook. self.exploration.before_compute_actions(explore=explore, timestep=timestep) if is_overridden(self.action_distribution_fn): dist_inputs, dist_class, state_out = self.action_distribution_fn( self.model, obs_batch=input_dict, state_batches=state_batches, seq_lens=seq_lens, explore=explore, timestep=timestep, is_training=False, ) else: dist_class = self.dist_class dist_inputs, state_out = self.model(input_dict, state_batches, seq_lens) if not ( isinstance(dist_class, functools.partial) or issubclass(dist_class, TorchDistributionWrapper) ): raise ValueError( "`dist_class` ({}) not a TorchDistributionWrapper " "subclass! Make sure your `action_distribution_fn` or " "`make_model_and_action_dist` return a correct " "distribution class.".format(dist_class.__name__) ) action_dist = dist_class(dist_inputs, self.model) # Get the exploration action from the forward results. actions, logp = self.exploration.get_exploration_action( action_distribution=action_dist, timestep=timestep, explore=explore ) # Add default and custom fetches. if extra_fetches is None: extra_fetches = self.extra_action_out( input_dict, state_batches, self.model, action_dist ) # Action-dist inputs. if dist_inputs is not None: extra_fetches[SampleBatch.ACTION_DIST_INPUTS] = dist_inputs # Action-logp and action-prob. if logp is not None: extra_fetches[SampleBatch.ACTION_PROB] = torch.exp(logp.float()) extra_fetches[SampleBatch.ACTION_LOGP] = logp # Update our global timestep by the batch size. self.global_timestep += len(input_dict[SampleBatch.CUR_OBS]) return convert_to_numpy((actions, state_out, extra_fetches)) def _lazy_tensor_dict(self, postprocessed_batch: SampleBatch, device=None): if not isinstance(postprocessed_batch, SampleBatch): postprocessed_batch = SampleBatch(postprocessed_batch) postprocessed_batch.set_get_interceptor( functools.partial(convert_to_torch_tensor, device=device or self.device) ) return postprocessed_batch def _multi_gpu_parallel_grad_calc( self, sample_batches: List[SampleBatch] ) -> List[Tuple[List[TensorType], GradInfoDict]]: """Performs a parallelized loss and gradient calculation over the batch. Splits up the given train batch into n shards (n=number of this Policy's devices) and passes each data shard (in parallel) through the loss function using the individual devices' models (self.model_gpu_towers). Then returns each tower's outputs. Args: sample_batches: A list of SampleBatch shards to calculate loss and gradients for. Returns: A list (one item per device) of 2-tuples, each with 1) gradient list and 2) grad info dict. """ assert len(self.model_gpu_towers) == len(sample_batches) lock = threading.Lock() results = {} grad_enabled = torch.is_grad_enabled() def _worker(shard_idx, model, sample_batch, device): torch.set_grad_enabled(grad_enabled) try: with NullContextManager() if device.type == "cpu" else torch.cuda.device( # noqa: E501 device ): loss_out = force_list( self.loss(model, self.dist_class, sample_batch) ) # Call Model's custom-loss with Policy loss outputs and # train_batch. if hasattr(model, "custom_loss"): loss_out = model.custom_loss(loss_out, sample_batch) assert len(loss_out) == len(self._optimizers) # Loop through all optimizers. grad_info = {"allreduce_latency": 0.0} parameters = list(model.parameters()) all_grads = [None for _ in range(len(parameters))] for opt_idx, opt in enumerate(self._optimizers): # Erase gradients in all vars of the tower that this # optimizer would affect. param_indices = self.multi_gpu_param_groups[opt_idx] for param_idx, param in enumerate(parameters): if param_idx in param_indices and param.grad is not None: # Recompute gradients of loss over all variables. loss_out[opt_idx].backward(retain_graph=True) grad_info.update( self.extra_grad_process(opt, loss_out[opt_idx]) ) grads = [] # Note that return values are just references; # Calling zero_grad would modify the values. for param_idx, param in enumerate(parameters): if param_idx in param_indices: if param.grad is not None: grads.append(param.grad) all_grads[param_idx] = param.grad if self.distributed_world_size: start = time.time() if torch.cuda.is_available(): # Sadly, allreduce_coalesced does not work with # CUDA yet. for g in grads: torch.distributed.all_reduce( g, op=torch.distributed.ReduceOp.SUM ) else: torch.distributed.all_reduce_coalesced( grads, op=torch.distributed.ReduceOp.SUM ) for param_group in opt.param_groups: for p in param_group["params"]: if p.grad is not None: p.grad /= self.distributed_world_size grad_info["allreduce_latency"] += time.time() - start with lock: results[shard_idx] = (all_grads, grad_info) except Exception as e: import traceback with lock: results[shard_idx] = ( ValueError( e.args[0] + "\n traceback" + traceback.format_exc() + "\n" + "In tower {} on device {}".format(shard_idx, device) ), e, ) # Single device (GPU) or fake-GPU case (serialize for better # debugging). if len(self.devices) == 1 or self.config["_fake_gpus"]: for shard_idx, (model, sample_batch, device) in enumerate( zip(self.model_gpu_towers, sample_batches, self.devices) ): _worker(shard_idx, model, sample_batch, device) # Raise errors right away for better debugging. last_result = results[len(results) - 1] if isinstance(last_result[0], ValueError): raise last_result[0] from last_result[1] # Multi device (GPU) case: Parallelize via threads. else: threads = [ threading.Thread( target=_worker, args=(shard_idx, model, sample_batch, device) ) for shard_idx, (model, sample_batch, device) in enumerate( zip(self.model_gpu_towers, sample_batches, self.devices) ) ] for thread in threads: thread.start() for thread in threads: thread.join() # Gather all threads' outputs and return. outputs = [] for shard_idx in range(len(sample_batches)): output = results[shard_idx] if isinstance(output[0], Exception): raise output[0] from output[1] outputs.append(results[shard_idx]) return outputs