import logging from ray.rllib.agents.trainer import with_common_config from ray.rllib.agents.trainer_template import build_trainer from ray.rllib.agents.dqn.dqn_policy import DQNTFPolicy from ray.rllib.agents.dqn.simple_q_policy import SimpleQPolicy from ray.rllib.optimizers import SyncReplayOptimizer from ray.rllib.optimizers.replay_buffer import ReplayBuffer from ray.rllib.policy.sample_batch import DEFAULT_POLICY_ID from ray.rllib.utils.deprecation import deprecation_warning, DEPRECATED_VALUE from ray.rllib.utils.exploration import PerWorkerEpsilonGreedy from ray.rllib.utils.experimental_dsl import ( ParallelRollouts, Concurrently, StoreToReplayBuffer, LocalReplay, TrainOneStep, StandardMetricsReporting, UpdateTargetNetwork) logger = logging.getLogger(__name__) # yapf: disable # __sphinx_doc_begin__ DEFAULT_CONFIG = with_common_config({ # === Model === # Number of atoms for representing the distribution of return. When # this is greater than 1, distributional Q-learning is used. # the discrete supports are bounded by v_min and v_max "num_atoms": 1, "v_min": -10.0, "v_max": 10.0, # Whether to use noisy network "noisy": False, # control the initial value of noisy nets "sigma0": 0.5, # Whether to use dueling dqn "dueling": True, # Whether to use double dqn "double_q": True, # Postprocess model outputs with these hidden layers to compute the # state and action values. See also the model config in catalog.py. "hiddens": [256], # N-step Q learning "n_step": 1, # === Exploration Settings (Experimental) === "exploration_config": { # The Exploration class to use. "type": "EpsilonGreedy", # Config for the Exploration class' constructor: "initial_epsilon": 1.0, "final_epsilon": 0.02, "epsilon_timesteps": 10000, # Timesteps over which to anneal epsilon. # For soft_q, use: # "exploration_config" = { # "type": "SoftQ" # "temperature": [float, e.g. 1.0] # } }, # Switch to greedy actions in evaluation workers. "evaluation_config": { "explore": False, }, # TODO(sven): Make Exploration class for parameter noise. # If True parameter space noise will be used for exploration # See https://blog.openai.com/better-exploration-with-parameter-noise/ "parameter_noise": False, # Minimum env steps to optimize for per train call. This value does # not affect learning, only the length of iterations. "timesteps_per_iteration": 1000, # Update the target network every `target_network_update_freq` steps. "target_network_update_freq": 500, # === Replay buffer === # Size of the replay buffer. Note that if async_updates is set, then # each worker will have a replay buffer of this size. "buffer_size": 50000, # If True prioritized replay buffer will be used. "prioritized_replay": True, # Alpha parameter for prioritized replay buffer. "prioritized_replay_alpha": 0.6, # Beta parameter for sampling from prioritized replay buffer. "prioritized_replay_beta": 0.4, # Final value of beta (by default, we use constant beta=0.4). "final_prioritized_replay_beta": 0.4, # Time steps over which the beta parameter is annealed. "prioritized_replay_beta_annealing_timesteps": 20000, # Epsilon to add to the TD errors when updating priorities. "prioritized_replay_eps": 1e-6, # Whether to LZ4 compress observations "compress_observations": True, # === Optimization === # Learning rate for adam optimizer "lr": 5e-4, # Learning rate schedule "lr_schedule": None, # Adam epsilon hyper parameter "adam_epsilon": 1e-8, # If not None, clip gradients during optimization at this value "grad_norm_clipping": 40, # How many steps of the model to sample before learning starts. "learning_starts": 1000, # Update the replay buffer with this many samples at once. Note that # this setting applies per-worker if num_workers > 1. "sample_batch_size": 4, # Size of a batched sampled from replay buffer for training. Note that # if async_updates is set, then each worker returns gradients for a # batch of this size. "train_batch_size": 32, # === Parallelism === # Number of workers for collecting samples with. This only makes sense # to increase if your environment is particularly slow to sample, or if # you"re using the Async or Ape-X optimizers. "num_workers": 0, # Whether to compute priorities on workers. "worker_side_prioritization": False, # Prevent iterations from going lower than this time span "min_iter_time_s": 1, # DEPRECATED VALUES (set to -1 to indicate they have not been overwritten # by user's config). If we don't set them here, we will get an error # from the config-key checker. "schedule_max_timesteps": DEPRECATED_VALUE, "exploration_final_eps": DEPRECATED_VALUE, "exploration_fraction": DEPRECATED_VALUE, "beta_annealing_fraction": DEPRECATED_VALUE, "per_worker_exploration": DEPRECATED_VALUE, "softmax_temp": DEPRECATED_VALUE, "soft_q": DEPRECATED_VALUE, }) # __sphinx_doc_end__ # yapf: enable def make_policy_optimizer(workers, config): """Create the single process DQN policy optimizer. Returns: SyncReplayOptimizer: Used for generic off-policy Trainers. """ return SyncReplayOptimizer( workers, # TODO(sven): Move all PR-beta decays into Schedule components. learning_starts=config["learning_starts"], buffer_size=config["buffer_size"], prioritized_replay=config["prioritized_replay"], prioritized_replay_alpha=config["prioritized_replay_alpha"], prioritized_replay_beta=config["prioritized_replay_beta"], prioritized_replay_beta_annealing_timesteps=config[ "prioritized_replay_beta_annealing_timesteps"], final_prioritized_replay_beta=config["final_prioritized_replay_beta"], prioritized_replay_eps=config["prioritized_replay_eps"], train_batch_size=config["train_batch_size"], **config["optimizer"]) def validate_config_and_setup_param_noise(config): """Checks and updates the config based on settings. Rewrites sample_batch_size to take into account n_step truncation. """ # PyTorch check. if config["use_pytorch"]: raise ValueError("DQN does not support PyTorch yet! Use tf instead.") # TODO(sven): Remove at some point. # Backward compatibility of epsilon-exploration config AND beta-annealing # fraction settings (both based on schedule_max_timesteps, which is # deprecated). schedule_max_timesteps = None if config.get("schedule_max_timesteps", DEPRECATED_VALUE) != \ DEPRECATED_VALUE: deprecation_warning( "schedule_max_timesteps", "exploration_config.epsilon_timesteps AND " "prioritized_replay_beta_annealing_timesteps") schedule_max_timesteps = config["schedule_max_timesteps"] if config.get("exploration_final_eps", DEPRECATED_VALUE) != \ DEPRECATED_VALUE: deprecation_warning("exploration_final_eps", "exploration_config.final_epsilon") if isinstance(config["exploration_config"], dict): config["exploration_config"]["final_epsilon"] = \ config.pop("exploration_final_eps") if config.get("exploration_fraction", DEPRECATED_VALUE) != \ DEPRECATED_VALUE: assert schedule_max_timesteps is not None deprecation_warning("exploration_fraction", "exploration_config.epsilon_timesteps") if isinstance(config["exploration_config"], dict): config["exploration_config"]["epsilon_timesteps"] = config.pop( "exploration_fraction") * schedule_max_timesteps if config.get("beta_annealing_fraction", DEPRECATED_VALUE) != \ DEPRECATED_VALUE: assert schedule_max_timesteps is not None deprecation_warning( "beta_annealing_fraction (decimal)", "prioritized_replay_beta_annealing_timesteps (int)") config["prioritized_replay_beta_annealing_timesteps"] = config.pop( "beta_annealing_fraction") * schedule_max_timesteps if config.get("per_worker_exploration", DEPRECATED_VALUE) != \ DEPRECATED_VALUE: deprecation_warning("per_worker_exploration", "exploration_config.type=PerWorkerEpsilonGreedy") if isinstance(config["exploration_config"], dict): config["exploration_config"]["type"] = PerWorkerEpsilonGreedy if config.get("softmax_temp", DEPRECATED_VALUE) != DEPRECATED_VALUE: deprecation_warning( "soft_q", "exploration_config={" "type=StochasticSampling, temperature=[float]" "}") if config.get("softmax_temp", 1.0) < 0.00001: logger.warning("softmax temp very low: Clipped it to 0.00001.") config["softmax_temperature"] = 0.00001 if config.get("soft_q", DEPRECATED_VALUE) != DEPRECATED_VALUE: deprecation_warning( "soft_q", "exploration_config={" "type=SoftQ, temperature=[float]" "}") config["exploration_config"] = { "type": "SoftQ", "temperature": config.get("softmax_temp", 1.0) } # Update effective batch size to include n-step adjusted_batch_size = max(config["sample_batch_size"], config.get("n_step", 1)) config["sample_batch_size"] = adjusted_batch_size # Setup parameter noise. if config.get("parameter_noise", False): if config["batch_mode"] != "complete_episodes": raise ValueError("Exploration with parameter space noise requires " "batch_mode to be complete_episodes.") if config.get("noisy", False): raise ValueError("Exploration with parameter space noise and " "noisy network cannot be used at the same time.") start_callback = config["callbacks"].get("on_episode_start") def on_episode_start(info): # as a callback function to sample and pose parameter space # noise on the parameters of network policies = info["policy"] for pi in policies.values(): pi.add_parameter_noise() if start_callback is not None: start_callback(info) config["callbacks"]["on_episode_start"] = on_episode_start end_callback = config["callbacks"].get("on_episode_end") def on_episode_end(info): # as a callback function to monitor the distance # between noisy policy and original policy policies = info["policy"] episode = info["episode"] model = policies[DEFAULT_POLICY_ID].model if hasattr(model, "pi_distance"): episode.custom_metrics["policy_distance"] = model.pi_distance if end_callback is not None: end_callback(info) config["callbacks"]["on_episode_end"] = on_episode_end def get_initial_state(config): return { "last_target_update_ts": 0, "num_target_updates": 0, } # TODO(sven): Move this to generic Trainer. Every Algo should do this. def update_worker_exploration(trainer): """Sets epsilon exploration values in all policies to updated values. According to current time-step. Args: trainer (Trainer): The Trainer object for the DQN. """ # Store some data for metrics after learning. global_timestep = trainer.optimizer.num_steps_sampled trainer.train_start_timestep = global_timestep # Get all current exploration-infos (from Policies, which cache this info). trainer.exploration_infos = trainer.workers.foreach_trainable_policy( lambda p, _: p.get_exploration_info()) def after_train_result(trainer, result): """Add some DQN specific metrics to results.""" global_timestep = trainer.optimizer.num_steps_sampled result.update( timesteps_this_iter=global_timestep - trainer.train_start_timestep, info=dict({ "exploration_infos": trainer.exploration_infos, "num_target_updates": trainer.state["num_target_updates"], }, **trainer.optimizer.stats())) def update_target_if_needed(trainer, fetches): """Update the target network in configured intervals.""" global_timestep = trainer.optimizer.num_steps_sampled if global_timestep - trainer.state["last_target_update_ts"] > \ trainer.config["target_network_update_freq"]: trainer.workers.local_worker().foreach_trainable_policy( lambda p, _: p.update_target()) trainer.state["last_target_update_ts"] = global_timestep trainer.state["num_target_updates"] += 1 # Experimental distributed execution impl; enable with "use_exec_api": True. def execution_plan(workers, config): local_replay_buffer = ReplayBuffer(config["buffer_size"]) rollouts = ParallelRollouts(workers, mode="bulk_sync") # We execute the following steps concurrently: # (1) Generate rollouts and store them in our local replay buffer. Calling # next() on store_op drives this. store_op = rollouts.for_each(StoreToReplayBuffer(local_replay_buffer)) # (2) Read and train on experiences from the replay buffer. Every batch # returned from the LocalReplay() iterator is passed to TrainOneStep to # take a SGD step, and then we decide whether to update the target network. replay_op = LocalReplay(local_replay_buffer, config["train_batch_size"]) \ .for_each(TrainOneStep(workers)) \ .for_each(UpdateTargetNetwork( workers, config["target_network_update_freq"])) # Alternate deterministically between (1) and (2). train_op = Concurrently([store_op, replay_op], mode="round_robin") return StandardMetricsReporting(train_op, workers, config) GenericOffPolicyTrainer = build_trainer( name="GenericOffPolicyAlgorithm", default_policy=None, default_config=DEFAULT_CONFIG, validate_config=validate_config_and_setup_param_noise, get_initial_state=get_initial_state, make_policy_optimizer=make_policy_optimizer, before_train_step=update_worker_exploration, after_optimizer_step=update_target_if_needed, after_train_result=after_train_result, execution_plan=execution_plan) DQNTrainer = GenericOffPolicyTrainer.with_updates( name="DQN", default_policy=DQNTFPolicy, default_config=DEFAULT_CONFIG) SimpleQTrainer = DQNTrainer.with_updates(default_policy=SimpleQPolicy)