Source code for nnabla_rl.algorithms.gail

# Copyright 2021 Sony Corporation.
# Copyright 2021,2022,2023,2024 Sony Group Corporation.
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# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
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#     http://www.apache.org/licenses/LICENSE-2.0
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# Unless required by applicable law or agreed to in writing, software
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# limitations under the License.

import random
from dataclasses import dataclass
from typing import Any, Dict, Optional, Union

import gym
import numpy as np

import nnabla as nn
import nnabla.functions as NF
import nnabla.solvers as NS
import nnabla_rl.environment_explorers as EE
import nnabla_rl.model_trainers as MT
import nnabla_rl.preprocessors as RP
from nnabla_rl.algorithm import Algorithm, AlgorithmConfig, eval_api
from nnabla_rl.algorithms.common_utils import (
    _StatePreprocessedRewardFunction,
    _StatePreprocessedStochasticPolicy,
    _StatePreprocessedVFunction,
    _StochasticPolicyActionSelector,
    compute_v_target_and_advantage,
)
from nnabla_rl.builders import ExplorerBuilder, ModelBuilder, PreprocessorBuilder, SolverBuilder
from nnabla_rl.environment_explorer import EnvironmentExplorer
from nnabla_rl.environments.environment_info import EnvironmentInfo
from nnabla_rl.model_trainers.model_trainer import ModelTrainer, TrainingBatch
from nnabla_rl.models import (
    GAILDiscriminator,
    GAILPolicy,
    GAILVFunction,
    Model,
    RewardFunction,
    StochasticPolicy,
    VFunction,
)
from nnabla_rl.preprocessors import Preprocessor
from nnabla_rl.replay_buffer import ReplayBuffer
from nnabla_rl.replay_buffers.buffer_iterator import BufferIterator
from nnabla_rl.utils import context
from nnabla_rl.utils.data import add_batch_dimension, marshal_experiences, set_data_to_variable
from nnabla_rl.utils.misc import create_variable


[docs]@dataclass class GAILConfig(AlgorithmConfig): """List of configurations for GAIL algorithm. Args: act_deterministic_in_eval (bool): Enable act deterministically at evalution. Defaults to True. discriminator_batch_size (bool): Trainig batch size of discriminator.\ Usually, discriminator_batch_size is the same as pi_batch_size. Defaults to 50000. discriminator_learning_rate (float): Learning rate which is set to the solvers of dicriminator function. \ You can customize/override the learning rate for each solver by implementing the \ (:py:class:`SolverBuilder <nnabla_rl.builders.SolverBuilder>`) by yourself. \ Defaults to 0.001. discriminator_update_frequency (int): Frequency (measured in the number of parameter update) \ of discriminator update. Defaults to 1. adversary_entropy_coef (float): Coefficient of entropy loss in dicriminator training. Defaults to 0.001. policy_update_frequency (int): Frequency (measured in the number of parameter update) \ of policy update. Defaults to 1. gamma (float): Discount factor of rewards. Defaults to 0.995. lmb (float): Scalar of lambda return's computation in GAE. Defaults to 0.97.\ This configuration is related to bias and variance of estimated value. \ If it is close to 0, estimated value is low-variance but biased.\ If it is close to 1, estimated value is unbiased but high-variance. num_steps_per_iteration (int): Number of steps per each training iteration for collecting on-policy experinces.\ Increasing this step size is effective to get precise parameters of policy and value function updating, \ but computational time of each iteration will increase. Defaults to 50000. pi_batch_size (int): Trainig batch size of policy. \ Usually, pi_batch_size is the same as num_steps_per_iteration. Defaults to 50000. sigma_kl_divergence_constraint (float): Constraint size of kl divergence \ between previous policy and updated policy. Defaults to 0.01. maximum_backtrack_numbers (int): Maximum backtrack numbers of linesearch. Defaults to 10. conjugate_gradient_damping (float): Damping size of conjugate gradient method. Defaults to 0.1. conjugate_gradient_iterations (int): Number of iterations of conjugate gradient method. Defaults to 10. vf_epochs (int): Number of epochs in each iteration. Defaults to 5. vf_batch_size (int): Training batch size of value function. Defaults to 128. vf_learning_rate (float): Learning rate which is set to the solvers of value function. \ You can customize/override the learning rate for each solver by implementing the \ (:py:class:`SolverBuilder <nnabla_rl.builders.SolverBuilder>`) by yourself. \ Defaults to 0.001. preprocess_state (bool): Enable preprocessing the states in the collected experiences \ before feeding as training batch. Defaults to True. """ # type declarations to type check with mypy # NOTE: declared variables are instance variable and NOT class variable, unless it is marked with ClassVar # See https://mypy.readthedocs.io/en/stable/class_basics.html for details preprocess_state: bool = True act_deterministic_in_eval: bool = True discriminator_batch_size: int = 50000 discriminator_learning_rate: float = 0.01 discriminator_update_frequency: int = 1 adversary_entropy_coef: float = 0.001 policy_update_frequency: int = 1 gamma: float = 0.995 lmb: float = 0.97 pi_batch_size: int = 50000 num_steps_per_iteration: int = 50000 sigma_kl_divergence_constraint: float = 0.01 maximum_backtrack_numbers: int = 10 conjugate_gradient_damping: float = 0.1 conjugate_gradient_iterations: int = 10 vf_epochs: int = 5 vf_batch_size: int = 128 vf_learning_rate: float = 1e-3 def __post_init__(self): """__post_init__ Check the values are in valid range. """ self._assert_between(self.pi_batch_size, 0, self.num_steps_per_iteration, "pi_batch_size") self._assert_positive(self.discriminator_learning_rate, "discriminator_learning_rate") self._assert_positive(self.discriminator_batch_size, "discriminator_batch_size") self._assert_positive(self.policy_update_frequency, "policy_update_frequency") self._assert_positive(self.discriminator_update_frequency, "discriminator_update_frequency") self._assert_positive(self.adversary_entropy_coef, "adversarial_entropy_coef") self._assert_between(self.gamma, 0.0, 1.0, "gamma") self._assert_between(self.lmb, 0.0, 1.0, "lmb") self._assert_positive(self.num_steps_per_iteration, "num_steps_per_iteration") self._assert_positive(self.sigma_kl_divergence_constraint, "sigma_kl_divergence_constraint") self._assert_positive(self.maximum_backtrack_numbers, "maximum_backtrack_numbers") self._assert_positive(self.conjugate_gradient_damping, "conjugate_gradient_damping") self._assert_positive(self.conjugate_gradient_iterations, "conjugate_gradient_iterations") self._assert_positive(self.vf_epochs, "vf_epochs") self._assert_positive(self.vf_batch_size, "vf_batch_size") self._assert_positive(self.vf_learning_rate, "vf_learning_rate")
class DefaultPreprocessorBuilder(PreprocessorBuilder): def build_preprocessor( # type: ignore[override] self, scope_name: str, env_info: EnvironmentInfo, algorithm_config: GAILConfig, **kwargs, ) -> Preprocessor: return RP.RunningMeanNormalizer(scope_name, env_info.state_shape, value_clip=(-5.0, 5.0)) class DefaultPolicyBuilder(ModelBuilder[StochasticPolicy]): def build_model( # type: ignore[override] self, scope_name: str, env_info: EnvironmentInfo, algorithm_config: GAILConfig, **kwargs, ) -> StochasticPolicy: return GAILPolicy(scope_name, env_info.action_dim) class DefaultVFunctionBuilder(ModelBuilder[VFunction]): def build_model( # type: ignore[override] self, scope_name: str, env_info: EnvironmentInfo, algorithm_config: GAILConfig, **kwargs, ) -> VFunction: return GAILVFunction(scope_name) class DefaultRewardFunctionBuilder(ModelBuilder[RewardFunction]): def build_model( # type: ignore[override] self, scope_name: str, env_info: EnvironmentInfo, algorithm_config: GAILConfig, **kwargs, ) -> RewardFunction: return GAILDiscriminator(scope_name) class DefaultVFunctionSolverBuilder(SolverBuilder): def build_solver( # type: ignore[override] self, env_info: EnvironmentInfo, algorithm_config: GAILConfig, **kwargs ) -> nn.solver.Solver: return NS.Adam(alpha=algorithm_config.vf_learning_rate) class DefaultRewardFunctionSolverBuilder(SolverBuilder): def build_solver( # type: ignore[override] self, env_info: EnvironmentInfo, algorithm_config: GAILConfig, **kwargs ) -> nn.solver.Solver: assert isinstance(algorithm_config, GAILConfig) return NS.Adam(alpha=algorithm_config.discriminator_learning_rate) class DefaultExplorerBuilder(ExplorerBuilder): def build_explorer( # type: ignore[override] self, env_info: EnvironmentInfo, algorithm_config: GAILConfig, algorithm: "GAIL", **kwargs, ) -> EnvironmentExplorer: explorer_config = EE.RawPolicyExplorerConfig( initial_step_num=algorithm.iteration_num, timelimit_as_terminal=False ) explorer = EE.RawPolicyExplorer( policy_action_selector=algorithm._exploration_action_selector, env_info=env_info, config=explorer_config ) return explorer
[docs]class GAIL(Algorithm): """Generative Adversarial Imitation Learning implementation. This class implements the Generative Adversarial Imitation Learning (GAIL) algorithm proposed by Jonathan Ho, et al. in the paper: "Generative Adversarial Imitation Learning" For detail see: https://arxiv.org/abs/1606.03476 This algorithm only supports online training. Args: env_or_env_info\ (gym.Env or :py:class:`EnvironmentInfo <nnabla_rl.environments.environment_info.EnvironmentInfo>`): the environment to train or environment info expert_buffer (:py:class:`ReplayBuffer <nnabla_rl.replay_buffer.ReplayBuffer>`): replay buffer which contains expert experience. config (:py:class:`GAILConfig <nnabla_rl.algorithms.gail.GAILConfig>`): configuration of GAIL algorithm v_function_builder (:py:class:`ModelBuilder[VFunction] <nnabla_rl.builders.ModelBuilder>`): builder of v function models v_solver_builder (:py:class:`SolverBuilder <nnabla_rl.builders.SolverBuilder>`): builder for v function solvers policy_builder (:py:class:`ModelBuilder[StochasicPolicy] <nnabla_rl.builders.ModelBuilder>`): builder of policy models reward_function_builder (:py:class:`ModelBuilder[RewardFunction] <nnabla_rl.builders.ModelBuilder>`): builder of reward function models reward_solver_builder (:py:class:`SolverBuilder <nnabla_rl.builders.SolverBuilder>`): builder for reward function solvers state_preprocessor_builder (None or :py:class:`PreprocessorBuilder <nnabla_rl.builders.PreprocessorBuilder>`): state preprocessor builder to preprocess the states explorer_builder (:py:class:`ExplorerBuilder <nnabla_rl.builders.ExplorerBuilder>`): builder of environment explorer """ _config: GAILConfig _v_function: VFunction _v_function_solver: nn.solver.Solver _policy: StochasticPolicy _discriminator: RewardFunction _discriminator_solver: nn.solver.Solver _explorer_builder: ExplorerBuilder _environment_explorer: EnvironmentExplorer _v_function_trainer: ModelTrainer _policy_trainer: ModelTrainer _discriminator_trainer: ModelTrainer _s_var_label: nn.Variable _s_next_var_label: nn.Variable _a_var_label: nn.Variable _reward: nn.Variable _v_function_trainer_state: Dict[str, Any] _policy_trainer_state: Dict[str, Any] _discriminator_trainer_state: Dict[str, Any] _evaluation_actor: _StochasticPolicyActionSelector _exploration_actor: _StochasticPolicyActionSelector def __init__( self, env_or_env_info: Union[gym.Env, EnvironmentInfo], expert_buffer: ReplayBuffer, config: GAILConfig = GAILConfig(), v_function_builder: ModelBuilder[VFunction] = DefaultVFunctionBuilder(), v_solver_builder: SolverBuilder = DefaultVFunctionSolverBuilder(), policy_builder: ModelBuilder[StochasticPolicy] = DefaultPolicyBuilder(), reward_function_builder: ModelBuilder[RewardFunction] = DefaultRewardFunctionBuilder(), reward_solver_builder: SolverBuilder = DefaultRewardFunctionSolverBuilder(), state_preprocessor_builder: Optional[PreprocessorBuilder] = DefaultPreprocessorBuilder(), explorer_builder: ExplorerBuilder = DefaultExplorerBuilder(), ): super(GAIL, self).__init__(env_or_env_info, config=config) self._explorer_builder = explorer_builder with nn.context_scope(context.get_nnabla_context(self._config.gpu_id)): policy = policy_builder("pi", self._env_info, self._config) v_function = v_function_builder("v", self._env_info, self._config) discriminator = reward_function_builder("discriminator", self._env_info, self._config) if self._config.preprocess_state: if state_preprocessor_builder is None: raise ValueError("State preprocessing is enabled but no preprocessor builder is given") pi_v_preprocessor = state_preprocessor_builder("pi_v_preprocessor", self._env_info, self._config) v_function = _StatePreprocessedVFunction(v_function=v_function, preprocessor=pi_v_preprocessor) policy = _StatePreprocessedStochasticPolicy(policy=policy, preprocessor=pi_v_preprocessor) r_preprocessor = state_preprocessor_builder("r_preprocessor", self._env_info, self._config) discriminator = _StatePreprocessedRewardFunction( reward_function=discriminator, preprocessor=r_preprocessor ) self._pi_v_state_preprocessor = pi_v_preprocessor self._r_state_preprocessor = r_preprocessor self._v_function = v_function self._policy = policy self._discriminator = discriminator self._v_function_solver = v_solver_builder(self._env_info, self._config) self._discriminator_solver = reward_solver_builder(self._env_info, self._config) self._expert_buffer = expert_buffer self._evaluation_actor = _StochasticPolicyActionSelector( self._env_info, self._policy.shallowcopy(), deterministic=self._config.act_deterministic_in_eval ) self._exploration_actor = _StochasticPolicyActionSelector( self._env_info, self._policy.shallowcopy(), deterministic=False ) @eval_api def compute_eval_action(self, state, *, begin_of_episode=False, extra_info={}): with nn.context_scope(context.get_nnabla_context(self._config.gpu_id)): action, _ = self._evaluation_action_selector(state, begin_of_episode=begin_of_episode) return action def _before_training_start(self, env_or_buffer): # set context globally to ensure that the training runs on configured gpu context.set_nnabla_context(self._config.gpu_id) self._environment_explorer = self._setup_environment_explorer(env_or_buffer) self._v_function_trainer = self._setup_v_function_training(env_or_buffer) self._policy_trainer = self._setup_policy_training(env_or_buffer) self._discriminator_trainer = self._setup_reward_function_training(env_or_buffer) def _setup_environment_explorer(self, env_or_buffer): return None if self._is_buffer(env_or_buffer) else self._explorer_builder(self._env_info, self._config, self) def _setup_v_function_training(self, env_or_buffer): v_function_trainer_config = MT.v_value_trainers.MonteCarloVTrainerConfig( reduction_method="mean", v_loss_scalar=1.0 ) v_function_trainer = MT.v_value_trainers.MonteCarloVTrainer( train_functions=self._v_function, solvers={self._v_function.scope_name: self._v_function_solver}, env_info=self._env_info, config=v_function_trainer_config, ) return v_function_trainer def _setup_policy_training(self, env_or_buffer): policy_trainer_config = MT.policy_trainers.TRPOPolicyTrainerConfig( sigma_kl_divergence_constraint=self._config.sigma_kl_divergence_constraint, maximum_backtrack_numbers=self._config.maximum_backtrack_numbers, conjugate_gradient_damping=self._config.conjugate_gradient_damping, conjugate_gradient_iterations=self._config.conjugate_gradient_iterations, ) policy_trainer = MT.policy_trainers.TRPOPolicyTrainer( model=self._policy, env_info=self._env_info, config=policy_trainer_config ) return policy_trainer def _setup_reward_function_training(self, env_or_buffer): reward_function_trainer_config = MT.reward_trainiers.GAILRewardFunctionTrainerConfig( batch_size=self._config.discriminator_batch_size, learning_rate=self._config.discriminator_learning_rate, entropy_coef=self._config.adversary_entropy_coef, ) reward_function_trainer = MT.reward_trainiers.GAILRewardFunctionTrainer( models=self._discriminator, solvers={self._discriminator.scope_name: self._discriminator_solver}, env_info=self._env_info, config=reward_function_trainer_config, ) return reward_function_trainer def _run_online_training_iteration(self, env): if self.iteration_num % self._config.num_steps_per_iteration != 0: return buffer = ReplayBuffer(capacity=self._config.num_steps_per_iteration) num_steps = 0 while num_steps <= self._config.num_steps_per_iteration: experience = self._environment_explorer.rollout(env) experience = self._label_experience(experience) buffer.append(experience) num_steps += len(experience) self._gail_training(buffer) def _label_experience(self, experience): labeled_experience = [] if not hasattr(self, "_s_var_label"): # build graph self._s_var_label = create_variable(1, self._env_info.state_shape) self._s_next_var_label = create_variable(1, self._env_info.state_shape) self._a_var_label = create_variable(1, self._env_info.action_shape) logits_fake = self._discriminator.r(self._s_var_label, self._a_var_label, self._s_next_var_label) self._reward = -NF.log(1.0 - NF.sigmoid(logits_fake) + 1e-8) for s, a, _, non_terminal, n_s, info in experience: # forward and get reward set_data_to_variable(self._s_var_label, add_batch_dimension(s)) set_data_to_variable(self._a_var_label, add_batch_dimension(a)) set_data_to_variable(self._s_next_var_label, add_batch_dimension(n_s)) self._reward.forward() transition = (s, a, self._reward.d, non_terminal, n_s, info) labeled_experience.append(transition) return labeled_experience def _run_offline_training_iteration(self, buffer): raise NotImplementedError def _gail_training(self, buffer): buffer_iterator = BufferIterator(buffer, 1, shuffle=False, repeat=False) # policy learning if self._iteration_num % self._config.policy_update_frequency == 0: s, a, v_target, advantage = self._align_policy_experiences(buffer_iterator) if self._config.preprocess_state: self._pi_v_state_preprocessor.update(s) self._policy_training(s, a, v_target, advantage) self._v_function_training(s, v_target) # discriminator learning if self._iteration_num % self._config.discriminator_update_frequency == 0: s_curr_expert, a_curr_expert, s_next_expert, s_curr_agent, a_curr_agent, s_next_agent = ( self._align_discriminator_experiences(buffer_iterator) ) if self._config.preprocess_state: self._r_state_preprocessor.update(np.concatenate([s_curr_agent, s_curr_expert], axis=0)) self._discriminator_training( s_curr_expert, a_curr_expert, s_next_expert, s_curr_agent, a_curr_agent, s_next_agent ) def _align_policy_experiences(self, buffer_iterator): v_target_batch, adv_batch = self._compute_v_target_and_advantage(buffer_iterator) s_batch, a_batch, _ = self._align_state_and_action(buffer_iterator) return ( s_batch[: self._config.num_steps_per_iteration], a_batch[: self._config.num_steps_per_iteration], v_target_batch[: self._config.num_steps_per_iteration], adv_batch[: self._config.num_steps_per_iteration], ) def _compute_v_target_and_advantage(self, buffer_iterator): v_target_batch = [] adv_batch = [] buffer_iterator.reset() for experiences, *_ in buffer_iterator: # length of experiences is 1 v_target, adv = compute_v_target_and_advantage( self._v_function, experiences[0], gamma=self._config.gamma, lmb=self._config.lmb ) v_target_batch.append(v_target.reshape(-1, 1)) adv_batch.append(adv.reshape(-1, 1)) adv_batch = np.concatenate(adv_batch, axis=0) v_target_batch = np.concatenate(v_target_batch, axis=0) adv_mean = np.mean(adv_batch) adv_std = np.std(adv_batch) adv_batch = (adv_batch - adv_mean) / adv_std return v_target_batch, adv_batch def _align_state_and_action(self, buffer_iterator, batch_size=None): s_batch = [] a_batch = [] s_next_batch = [] buffer_iterator.reset() for experiences, _ in buffer_iterator: # length of experiences is 1 s_seq, a_seq, _, _, s_next_seq, *_ = marshal_experiences(experiences[0]) s_batch.append(s_seq) a_batch.append(a_seq) s_next_batch.append(s_next_seq) s_batch = np.concatenate(s_batch, axis=0) a_batch = np.concatenate(a_batch, axis=0) s_next_batch = np.concatenate(s_next_batch, axis=0) if batch_size is None: return s_batch, a_batch, s_next_batch idx = random.sample(list(range(s_batch.shape[0])), batch_size) return s_batch[idx], a_batch[idx], s_next_batch[idx] def _align_discriminator_experiences(self, buffer_iterator): # sample expert data expert_experience, _ = self._expert_buffer.sample(self._config.discriminator_batch_size) s_expert_batch, a_expert_batch, _, _, s_next_expert_batch, *_ = marshal_experiences(expert_experience) # sample agent data s_batch, a_batch, s_next_batch = self._align_state_and_action( buffer_iterator, batch_size=self._config.discriminator_batch_size ) return s_expert_batch, a_expert_batch, s_next_expert_batch, s_batch, a_batch, s_next_batch def _v_function_training(self, s, v_target): num_iterations_per_epoch = self._config.num_steps_per_iteration // self._config.vf_batch_size for _ in range(self._config.vf_epochs * num_iterations_per_epoch): indices = np.random.randint(0, self._config.num_steps_per_iteration, size=self._config.vf_batch_size) batch = TrainingBatch( batch_size=self._config.vf_batch_size, s_current=s[indices], extra={"v_target": v_target[indices]} ) self._v_function_trainer_state = self._v_function_trainer.train(batch) def _policy_training(self, s, a, v_target, advantage): extra = {} extra["v_target"] = v_target[: self._config.pi_batch_size] extra["advantage"] = advantage[: self._config.pi_batch_size] batch = TrainingBatch( batch_size=self._config.pi_batch_size, s_current=s[: self._config.pi_batch_size], a_current=a[: self._config.pi_batch_size], extra=extra, ) self._policy_trainer_state = self._policy_trainer.train(batch) def _discriminator_training( self, s_curr_expert, a_curr_expert, s_next_expert, s_curr_agent, a_curr_agent, s_next_agent ): extra = {} extra["s_current_agent"] = s_curr_agent[: self._config.discriminator_batch_size] extra["a_current_agent"] = a_curr_agent[: self._config.discriminator_batch_size] extra["s_next_agent"] = s_next_agent[: self._config.discriminator_batch_size] extra["s_current_expert"] = s_curr_expert[: self._config.discriminator_batch_size] extra["a_current_expert"] = a_curr_expert[: self._config.discriminator_batch_size] extra["s_next_expert"] = s_next_expert[: self._config.discriminator_batch_size] batch = TrainingBatch(batch_size=self._config.discriminator_batch_size, extra=extra) self._discriminator_trainer_state = self._discriminator_trainer.train(batch) def _evaluation_action_selector(self, s, *, begin_of_episode=False): return self._evaluation_actor(s, begin_of_episode=begin_of_episode) def _exploration_action_selector(self, s, *, begin_of_episode=False): return self._exploration_actor(s, begin_of_episode=begin_of_episode) def _models(self): models = {} models[self._policy.scope_name] = self._policy models[self._v_function.scope_name] = self._v_function models[self._discriminator.scope_name] = self._discriminator if self._config.preprocess_state and isinstance(self._r_state_preprocessor, Model): models[self._r_state_preprocessor.scope_name] = self._r_state_preprocessor if self._config.preprocess_state and isinstance(self._pi_v_state_preprocessor, Model): models[self._pi_v_state_preprocessor.scope_name] = self._pi_v_state_preprocessor return models def _solvers(self): solvers = {} solvers[self._v_function.scope_name] = self._v_function_solver solvers[self._discriminator.scope_name] = self._discriminator_solver return solvers
[docs] @classmethod def is_supported_env(cls, env_or_env_info): env_info = ( EnvironmentInfo.from_env(env_or_env_info) if isinstance(env_or_env_info, gym.Env) else env_or_env_info ) return not env_info.is_discrete_action_env() and not env_info.is_tuple_action_env()
@property def latest_iteration_state(self): latest_iteration_state = super(GAIL, self).latest_iteration_state if hasattr(self, "_discriminator_trainer_state"): latest_iteration_state["scalar"].update( {"reward_loss": float(self._discriminator_trainer_state["reward_loss"])} ) if hasattr(self, "_v_function_trainer_state"): latest_iteration_state["scalar"].update({"v_loss": float(self._v_function_trainer_state["v_loss"])}) return latest_iteration_state @property def trainers(self): return { "discriminator": self._discriminator_trainer, "v_function": self._v_function_trainer, "policy": self._policy_trainer, }