Esempio n. 1
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    def __init__(self, trainer_config_path, model_path):

        self.brain = BrainParameters(
            brain_name='Learner',
            camera_resolutions=[{
                'height': 84,
                'width': 84,
                'blackAndWhite': False
            }],
            num_stacked_vector_observations=1,
            vector_action_descriptions=['', ''],
            vector_action_space_size=[3, 3],
            vector_action_space_type=0,  # corresponds to discrete
            vector_observation_space_size=3)

        self.trainer_params = yaml.load(open(trainer_config_path))['Learner']
        self.trainer_params['keep_checkpoints'] = 0
        self.trainer_params['model_path'] = model_path
        self.trainer_params['use_recurrent'] = False

        self.policy = PPOPolicy(brain=self.brain,
                                seed=0,
                                trainer_params=self.trainer_params,
                                is_training=False,
                                load=True)
Esempio n. 2
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class Agent(object):
    def __init__(self, trainer_config_path, model_path):

        self.brain = BrainParameters(
            brain_name='Learner',
            camera_resolutions=[{
                'height': 84,
                'width': 84,
                'blackAndWhite': False
            }],
            num_stacked_vector_observations=1,
            vector_action_descriptions=['', ''],
            vector_action_space_size=[3, 3],
            vector_action_space_type=0,  # corresponds to discrete
            vector_observation_space_size=3)

        self.trainer_params = yaml.load(open(trainer_config_path))['Learner']
        self.trainer_params['keep_checkpoints'] = 0
        self.trainer_params['model_path'] = model_path
        self.trainer_params['use_recurrent'] = False

        self.policy = PPOPolicy(brain=self.brain,
                                seed=0,
                                trainer_params=self.trainer_params,
                                is_training=False,
                                load=True)

    def reset(self, t=250):
        pass

    def fix_brain_info(self, brain_info):
        if brain_info.vector_observations.shape[1] > 3:
            # カスタム環境用にvector_observationsをいじったものだった場合
            velocity = brain_info.vector_observations[:, :3]

            extended_infos = brain_info.vector_observations[:, 3:]
            # 元の3次元だけのvector_observationsに戻す
            brain_info.vector_observations = brain_info.vector_observations[:, :
                                                                            3]
            agent_pos = extended_infos[:, :3]
            agent_angle = extended_infos[:, 3]
            return (velocity[0], agent_pos[0], agent_angle[0])
        else:
            print("There was no extended brain info")
            return None

    def step(self, obs, reward, done, info):
        brain_info = info['brain_info']
        velocity_pos_angle = self.fix_brain_info(brain_info)  # Custom環境でのみの情報

        out = self.policy.evaluate(brain_info=brain_info)
        action = out['action']
        log_probs = out['log_probs']
        value = out['value']
        entropy = out['entropy']
        return action, log_probs, value, entropy, velocity_pos_angle
Esempio n. 3
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    def __init__(self, trainer_config_path, model_path):

        self.brain = BrainParameters(
            brain_name='Learner',
            camera_resolutions=[{
                'height': 84,
                'width': 84,
                'blackAndWhite': False
            }],
            num_stacked_vector_observations=1,
            vector_action_descriptions=['', ''],
            vector_action_space_size=[3, 3],
            vector_action_space_type=0,  # corresponds to discrete
            vector_observation_space_size=3)

        if ENABLE_VISITED_MAP_IMAGE:
            self.brain = add_extra_camera_parameter(
                self.brain, USE_FIXED_VISITED_MAP_COORDINATE,
                USE_LIDAR_VECTOR_INFO)
            self.extra_brain_info = ExtraBrainInfo()
        else:
            self.extra_brain_info = None

        self.trainer_params = yaml.load(open(trainer_config_path))['Learner']
        self.trainer_params['keep_checkpoints'] = 0
        self.trainer_params['model_path'] = model_path

        self.policy = PPOPolicy(brain=self.brain,
                                seed=0,
                                trainer_params=self.trainer_params,
                                is_training=False,
                                load=True)

        self.lidar_estimator = MultiLidarEstimator(
            save_dir="saved_lidar",  # データパスの指定
            n_arenas=1)
Esempio n. 4
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class Agent(object):
    def __init__(self,
                 trainer_config_path,
                 model_path):

        self.brain = BrainParameters(
            brain_name = 'Learner',
            camera_resolutions = [{
                'height': 84,
                'width' : 84,
                'blackAndWhite': False
            }],
            num_stacked_vector_observations = 1,
            vector_action_descriptions    = ['', ''],
            vector_action_space_size      = [3, 3],
            vector_action_space_type      = 0,  # corresponds to discrete
            vector_observation_space_size = 3
        )
        
        self.trainer_params = yaml.load(open(trainer_config_path))['Learner']
        self.trainer_params['keep_checkpoints'] = 0
        self.trainer_params['model_path']       = model_path

        self.policy = PPOPolicy(brain=self.brain,
                                seed=0,
                                trainer_params=self.trainer_params,
                                is_training=False,
                                load=True)

    def reset(self, t=250):
        pass

    def fix_brain_info(self, brain_info):
        velocity = brain_info.vector_observations[:,:3]
        
        if brain_info.vector_observations.shape[1] > 3:
            # カスタム環境用にvector_observationsをいじったものだった場合
            extended_infos = brain_info.vector_observations[:,3:]
            
            # 元の3次元だけのvector_observationsに戻す
            brain_info.vector_observations = brain_info.vector_observations[:,:3]
            agent_pos   = extended_infos[:,:3]
            agent_angle = extended_infos[:,3] / 360.0 * (2.0 * np.pi) # 0~2pi
            
            target_ids       = extended_infos[:,4:4+5].astype(np.int32)
            target_distances = extended_infos[:,9:9+5]
            
            return velocity[0], (agent_pos[0], agent_angle[0]), \
                (target_ids[0], target_distances[0])
        else:
            return velocity[0], None, None

    def step(self, obs, reward, done, info):
        brain_info = info['brain_info']
        out = self.fix_brain_info(brain_info) # Custom環境でのみの情報
        velocity, pos_angle, target_ids_distances = out
        # (3,) (3,) (), ()
        
        out = self.policy.evaluate(brain_info=brain_info)
        action    = out['action']
        log_probs = out['log_probs']
        value     = out['value']
        entropy   = out['entropy']
        return action, log_probs, value, entropy, velocity, pos_angle, target_ids_distances
Esempio n. 5
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class Agent(object):
    def __init__(self, trainer_config_path, model_path):

        self.brain = BrainParameters(
            brain_name='Learner',
            camera_resolutions=[{
                'height': 84,
                'width': 84,
                'blackAndWhite': False
            }],
            num_stacked_vector_observations=1,
            vector_action_descriptions=['', ''],
            vector_action_space_size=[3, 3],
            vector_action_space_type=0,  # corresponds to discrete
            vector_observation_space_size=3)

        if ENABLE_VISITED_MAP_IMAGE:
            self.brain = add_extra_camera_parameter(
                self.brain, USE_FIXED_VISITED_MAP_COORDINATE,
                USE_LIDAR_VECTOR_INFO)
            self.extra_brain_info = ExtraBrainInfo()
        else:
            self.extra_brain_info = None

        self.trainer_params = yaml.load(open(trainer_config_path))['Learner']
        self.trainer_params['keep_checkpoints'] = 0
        self.trainer_params['model_path'] = model_path

        self.policy = PPOPolicy(brain=self.brain,
                                seed=0,
                                trainer_params=self.trainer_params,
                                is_training=False,
                                load=True)

        self.lidar_estimator = MultiLidarEstimator(
            save_dir="saved_lidar",  # データパスの指定
            n_arenas=1)

    def reset(self, t=250):
        if ENABLE_VISITED_MAP_IMAGE:
            self.extra_brain_info = ExtraBrainInfo()
            self.lidar_estimator.reset()

    def fix_brain_info(self, brain_info):
        velocity = brain_info.vector_observations[:, :3]

        if brain_info.vector_observations.shape[1] > 3:
            # カスタム環境用にvector_observationsをいじったものだった場合
            extended_infos = brain_info.vector_observations[:, 3:]

            # 元の3次元だけのvector_observationsに戻す
            brain_info.vector_observations = brain_info.vector_observations[:, :
                                                                            3]
            agent_pos = extended_infos[:, :3]
            agent_angle = extended_infos[:, 3] / 360.0 * (2.0 * np.pi)  # 0~2pi

            raw_target_ids = extended_infos[:, 4:4 + 5].astype(np.int32)
            target_distances = extended_infos[:, 9:9 + 5]

            # 共通するオブジェクトのIDをまとめる
            target_ids = convert_target_ids(raw_target_ids[0])

            return velocity[0], (agent_pos[0], agent_angle[0]), \
                (target_ids, target_distances[0])
        else:
            return velocity[0], None, None

    def step(self, obs, reward, done, info):
        brain_info = info['brain_info']

        out = self.fix_brain_info(brain_info)  # Custom環境でのみの情報
        velocity, pos_angle, target_ids_distances = out
        # (3,)

        if ENABLE_VISITED_MAP_IMAGE:
            brain_info, self.extra_brain_info = expand_brain_info(
                brain_info, self.extra_brain_info, self.lidar_estimator,
                USE_LIDAR_VECTOR_INFO)

        out = self.policy.evaluate(brain_info=brain_info)
        action = out['action']
        log_probs = out['log_probs']
        value = out['value']
        entropy = out['entropy']

        return action, log_probs, value, entropy, velocity, pos_angle, target_ids_distances
Esempio n. 6
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    def __init__(self,
                 brain,
                 reward_buff_cap,
                 trainer_parameters,
                 training,
                 load,
                 seed,
                 run_id):
        """
        Responsible for collecting experiences and training PPO model.

        :param trainer_parameters: 
            The parameters for the trainer (dictionary).
        :param training: 
            Whether the trainer is set for training.
        :param load: 
            Whether the model should be loaded.
        :param seed: 
            The seed the model will be initialized with
        :param run_id: 
            The The identifier of the current run
        """
        super(PPOTrainer, self).__init__(brain, trainer_parameters, training, run_id)
        
        self.param_keys = [
            'batch_size',
            'beta',
            'buffer_size',
            'epsilon',
            'gamma',
            'hidden_units',
            'lambd',
            'learning_rate',
            'max_steps',
            'normalize',
            'num_epoch',
            'num_layers',
            'time_horizon',
            'sequence_length',
            'summary_freq',
            'use_recurrent',
            'summary_path',
            'memory_size',
            'use_curiosity',
            'curiosity_strength',
            'curiosity_enc_size',
            'model_path'
        ]

        self.check_param_keys()
        self.use_curiosity = bool(trainer_parameters['use_curiosity'])
        self.step = 0
        self.policy = PPOPolicy(seed, brain, trainer_parameters,
                                self.is_training, load)

        stats = {
            'Environment/Cumulative Reward': [],
            'Environment/Episode Length': [],
            'Policy/Value Estimate': [],
            'Policy/Entropy': [],
            'Losses/Value Loss': [],
            'Losses/Policy Loss': [],
            'Policy/Learning Rate': []
        }
        
        if self.use_curiosity:
            stats['Losses/Forward Loss'] = []
            stats['Losses/Inverse Loss'] = []
            stats['Policy/Curiosity Reward'] = []
            self.intrinsic_rewards = {}

        self.stats = stats

        self.training_buffer = Buffer()
        self.cumulative_rewards = {}
        self._reward_buffer = deque(maxlen=reward_buff_cap)
        self.episode_steps = {}
        self.summary_path = trainer_parameters['summary_path']
        if not os.path.exists(self.summary_path):
            os.makedirs(self.summary_path)

        self.summary_writer = tf.summary.FileWriter(self.summary_path)
Esempio n. 7
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class PPOTrainer(Trainer):
    """The PPOTrainer is an implementation of the PPO algorithm."""

    def __init__(self,
                 brain,
                 reward_buff_cap,
                 trainer_parameters,
                 training,
                 load,
                 seed,
                 run_id):
        """
        Responsible for collecting experiences and training PPO model.

        :param trainer_parameters: 
            The parameters for the trainer (dictionary).
        :param training: 
            Whether the trainer is set for training.
        :param load: 
            Whether the model should be loaded.
        :param seed: 
            The seed the model will be initialized with
        :param run_id: 
            The The identifier of the current run
        """
        super(PPOTrainer, self).__init__(brain, trainer_parameters, training, run_id)
        
        self.param_keys = [
            'batch_size',
            'beta',
            'buffer_size',
            'epsilon',
            'gamma',
            'hidden_units',
            'lambd',
            'learning_rate',
            'max_steps',
            'normalize',
            'num_epoch',
            'num_layers',
            'time_horizon',
            'sequence_length',
            'summary_freq',
            'use_recurrent',
            'summary_path',
            'memory_size',
            'use_curiosity',
            'curiosity_strength',
            'curiosity_enc_size',
            'model_path'
        ]

        self.check_param_keys()
        self.use_curiosity = bool(trainer_parameters['use_curiosity'])
        self.step = 0
        self.policy = PPOPolicy(seed, brain, trainer_parameters,
                                self.is_training, load)

        stats = {
            'Environment/Cumulative Reward': [],
            'Environment/Episode Length': [],
            'Policy/Value Estimate': [],
            'Policy/Entropy': [],
            'Losses/Value Loss': [],
            'Losses/Policy Loss': [],
            'Policy/Learning Rate': []
        }
        
        if self.use_curiosity:
            stats['Losses/Forward Loss'] = []
            stats['Losses/Inverse Loss'] = []
            stats['Policy/Curiosity Reward'] = []
            self.intrinsic_rewards = {}

        self.stats = stats

        self.training_buffer = Buffer()
        self.cumulative_rewards = {}
        self._reward_buffer = deque(maxlen=reward_buff_cap)
        self.episode_steps = {}
        self.summary_path = trainer_parameters['summary_path']
        if not os.path.exists(self.summary_path):
            os.makedirs(self.summary_path)

        self.summary_writer = tf.summary.FileWriter(self.summary_path)

    def __str__(self):
        return '''Hyperparameters for the PPO Trainer of brain {0}: \n{1}'''.format(
            self.brain_name, '\n'.join(['\t{0}:\t{1}'.format(x,
                                                             self.trainer_parameters[x])
                                        for x in self.param_keys]))

    @property
    def parameters(self):
        """
        Returns the trainer parameters of the trainer.
        """
        return self.trainer_parameters

    @property
    def get_max_steps(self):
        """
        Returns the maximum number of steps. Is used to know when the trainer should be stopped.

        :return: 
            The maximum number of steps of the trainer
        """
        return float(self.trainer_parameters['max_steps'])

    @property
    def get_step(self):
        """
        Returns the number of steps the trainer has performed

        :return: 
            the step count of the trainer
        """
        return self.step

    @property
    def reward_buffer(self):
        """
        Returns the reward buffer. The reward buffer contains the cumulative
        rewards of the most recent episodes completed by agents using this
        trainer.

        :return: 
            the reward buffer.
        """
        return self._reward_buffer

    def increment_step_and_update_last_reward(self):
        """
        Increment the step count of the trainer and Updates the last reward
        """
        if len(self.stats['Environment/Cumulative Reward']) > 0:
            mean_reward = np.mean(self.stats['Environment/Cumulative Reward'])
            self.policy.update_reward(mean_reward)
        self.policy.increment_step()
        self.step = self.policy.get_current_step()

    def take_action(self, all_brain_info: AllBrainInfo):
        """
        Actionを決定する.
        Decides actions given observations information, and takes them in environment.

        :param all_brain_info: 
            A dictionary of brain names and BrainInfo from environment.
        :return: 
            a tuple containing action, memories, values and an object
            to be passed to add experiences
        """
        curr_brain_info = all_brain_info[self.brain_name]
        if len(curr_brain_info.agents) == 0:
            return [], [], [], None, None

        # PPOPolicyにてActionを決定
        run_out = self.policy.evaluate(curr_brain_info)

        self.stats['Policy/Value Estimate'].append(run_out['value'].mean())
        self.stats['Policy/Entropy'].append(run_out['entropy'].mean())
        self.stats['Policy/Learning Rate'].append(run_out['learning_rate'])
        
        if self.policy.use_recurrent:
            return run_out['action'], run_out['memory_out'], None, \
                   run_out['value'], run_out
        else:
            return run_out['action'], None, None, run_out['value'], run_out

    def construct_curr_info(self, next_info: BrainInfo) -> BrainInfo:
        """
        Constructs a BrainInfo which contains the most recent previous experiences 
        for all agents info which correspond to the agents in a provided next_info.

        :BrainInfo next_info: 
            A t+1 BrainInfo.
        :return: 
            curr_info: Reconstructed BrainInfo to match agents of next_info.
        """
        visual_observations = [[]]
        vector_observations = []
        text_observations   = []
        memories            = []
        rewards             = []
        local_dones         = []
        max_reacheds        = []
        agents              = []
        prev_vector_actions = []
        prev_text_actions   = []
        
        for agent_id in next_info.agents:
            agent_brain_info = self.training_buffer[agent_id].last_brain_info
            
            if agent_brain_info is None:
                agent_brain_info = next_info
            agent_index = agent_brain_info.agents.index(agent_id)
            
            for i in range(len(next_info.visual_observations)):
                visual_observations[i].append(
                    agent_brain_info.visual_observations[i][agent_index])
                
            vector_observations.append(agent_brain_info.vector_observations[agent_index])
            text_observations.append(agent_brain_info.text_observations[agent_index])
            
            if self.policy.use_recurrent:
                if len(agent_brain_info.memories > 0):
                    memories.append(agent_brain_info.memories[agent_index])
                else:
                    memories.append(self.policy.make_empty_memory(1))
                    
            rewards.append(agent_brain_info.rewards[agent_index])
            local_dones.append(agent_brain_info.local_done[agent_index])
            max_reacheds.append(agent_brain_info.max_reached[agent_index])
            agents.append(agent_brain_info.agents[agent_index])
            prev_vector_actions.append(agent_brain_info.previous_vector_actions[agent_index])
            prev_text_actions.append(agent_brain_info.previous_text_actions[agent_index])
            
        if self.policy.use_recurrent:
            memories = np.vstack(memories)
            
        curr_info = BrainInfo(visual_observations,
                              vector_observations,
                              text_observations,
                              memories,
                              rewards,
                              agents,
                              local_dones,
                              prev_vector_actions,
                              prev_text_actions,
                              max_reacheds)
        return curr_info

    def add_experiences(self,
                        curr_all_info: AllBrainInfo,
                        next_all_info: AllBrainInfo,
                        take_action_outputs):
        """
        Adds experiences to each agent's experience history.

        :curr_all_info: 
            Dictionary of all current brains and corresponding BrainInfo.
        :next_all_info: 
            Dictionary of all current brains and corresponding BrainInfo.
        :take_action_outputs: 
            The outputs of the take action method.
        """
        curr_info = curr_all_info[self.brain_name]
        next_info = next_all_info[self.brain_name]

        for agent_id in curr_info.agents:
            # AgentBuffer のlast_brain_info にとっておく
            self.training_buffer[agent_id].last_brain_info          = curr_info
            self.training_buffer[agent_id].last_take_action_outputs = take_action_outputs

        if curr_info.agents != next_info.agents:
            curr_to_use = self.construct_curr_info(next_info)
        else:
            curr_to_use = curr_info

        # 内部報酬の算出
        intrinsic_rewards = self.policy.get_intrinsic_rewards(curr_to_use, next_info)

        for agent_id in next_info.agents:
            # Arena毎にAgentがひとつある.
            # Agent毎にAgentBufferが用意されている.
            stored_info                = self.training_buffer[agent_id].last_brain_info
            stored_take_action_outputs = self.training_buffer[agent_id].last_take_action_outputs
            
            if stored_info is not None:
                idx      = stored_info.agents.index(agent_id)
                next_idx = next_info.agents.index(agent_id)
                
                if not stored_info.local_done[idx]:
                    # Not tarminal
                    for i, _ in enumerate(stored_info.visual_observations):
                        self.training_buffer[agent_id]['visual_obs%d' % i].append(
                            stored_info.visual_observations[i][idx])
                        self.training_buffer[agent_id]['next_visual_obs%d' % i].append(
                            next_info.visual_observations[i][next_idx])
                    if self.policy.use_vec_obs:
                        self.training_buffer[agent_id]['vector_obs'].append(
                            stored_info.vector_observations[idx])
                        self.training_buffer[agent_id]['next_vector_in'].append(
                            next_info.vector_observations[next_idx])
                    if self.policy.use_recurrent:
                        if stored_info.memories.shape[1] == 0:
                            stored_info.memories = np.zeros((len(stored_info.agents),
                                                             self.policy.m_size))
                        self.training_buffer[agent_id]['memory'].append(
                            stored_info.memories[idx])
                    actions = stored_take_action_outputs['action']
                    
                    self.training_buffer[agent_id]['action_mask'].append(
                        stored_info.action_masks[idx], padding_value=1)
                        
                    a_dist = stored_take_action_outputs['log_probs']
                    value  = stored_take_action_outputs['value']
                    
                    self.training_buffer[agent_id]['actions'].append(actions[idx])
                    self.training_buffer[agent_id]['prev_action'].append(
                        stored_info.previous_vector_actions[idx])
                    self.training_buffer[agent_id]['masks'].append(1.0)
                    
                    if self.use_curiosity:
                        self.training_buffer[agent_id]['rewards'].append(
                            next_info.rewards[next_idx] +
                            intrinsic_rewards[next_idx])
                    else:
                        self.training_buffer[agent_id]['rewards'].append(
                            next_info.rewards[next_idx])
                        
                    self.training_buffer[agent_id]['action_probs'].append(a_dist[idx])
                    self.training_buffer[agent_id]['value_estimates'].append(value[idx][0])
                    
                    if agent_id not in self.cumulative_rewards:
                        self.cumulative_rewards[agent_id] = 0
                        
                    self.cumulative_rewards[agent_id] += next_info.rewards[next_idx]
                    
                    if self.use_curiosity:
                        if agent_id not in self.intrinsic_rewards:
                            self.intrinsic_rewards[agent_id] = 0
                        self.intrinsic_rewards[agent_id] += intrinsic_rewards[next_idx]
                        
                if not next_info.local_done[next_idx]:
                    if agent_id not in self.episode_steps:
                        self.episode_steps[agent_id] = 0
                    self.episode_steps[agent_id] += 1

    def process_experiences(self,
                            current_info : AllBrainInfo,
                            new_info : AllBrainInfo):
        """
        Checks agent histories for processing condition, and processes them as necessary.
        Processing involves calculating value and advantage targets for model updating step.
        
        :current_info: 
            Dictionary of all current brains and corresponding BrainInfo.
        :new_info: 
            Dictionary of all next brains and corresponding BrainInfo.
        """

        info = new_info[self.brain_name]
        
        for l in range(len(info.agents)):
            # 各AgentにひとつあるAgentBufferから取得
            agent_actions = self.training_buffer[info.agents[l]]['actions']

            # time_horizon はデフォルトで128
            if ((info.local_done[l] or len(agent_actions) > self.trainer_parameters[
                    'time_horizon'])
                    and len(agent_actions) > 0):
                # Episodeがterminateした、または128 stepを超えた時
                agent_id = info.agents[l]
                
                if info.local_done[l] and not info.max_reached[l]:
                    value_next = 0.0
                else:
                    if info.max_reached[l]:
                        bootstrapping_info = self.training_buffer[agent_id].last_brain_info
                        idx = bootstrapping_info.agents.index(agent_id)
                    else:
                        bootstrapping_info = info
                        idx = l
                    value_next = self.policy.get_value_estimate(bootstrapping_info, idx)

                self.training_buffer[agent_id]['advantages'].set(
                    get_gae(
                        rewards=self.training_buffer[agent_id]['rewards'].get_batch(),
                        value_estimates=self.training_buffer[agent_id]['value_estimates'].get_batch(),
                        value_next=value_next,
                        gamma=self.trainer_parameters['gamma'],
                        lambd=self.trainer_parameters['lambd']))
                
                self.training_buffer[agent_id]['discounted_returns'].set(
                    self.training_buffer[agent_id]['advantages'].get_batch()
                    + self.training_buffer[agent_id]['value_estimates'].get_batch())

                # 各Agentバッファから共通のUpdateバッファへコピー.
                # Recurrent学習時はtraining_lengthは64とかになるが、非Recurrent時は1.
                # Recurrent学習時はsequence_length単位で1バッチとしてまとめられ、
                # 足りない部分は0でパディングされる.
                self.training_buffer.append_update_buffer(
                    agent_id,
                    batch_size=None,
                    training_length=self.policy.sequence_length)

                # AgentBufferを全クリア
                self.training_buffer[agent_id].reset_agent()
                
                if info.local_done[l]:
                    # 1Areaのエピソードが終了したので、統計情報用にreward,spidoe長等を記録しておく
                    self.stats['Environment/Cumulative Reward'].append(
                        self.cumulative_rewards.get(agent_id, 0))
                    self.reward_buffer.appendleft(self.cumulative_rewards.get(agent_id, 0))
                    self.stats['Environment/Episode Length'].append(
                        self.episode_steps.get(agent_id, 0))
                    self.cumulative_rewards[agent_id] = 0
                    self.episode_steps[agent_id] = 0
                    
                    if self.use_curiosity:
                        self.stats['Policy/Curiosity Reward'].append(
                            self.intrinsic_rewards.get(agent_id, 0))
                        self.intrinsic_rewards[agent_id] = 0

    def end_episode(self):
        """
        A signal that the Episode has ended. The buffer must be reset. 
        Get only called when the academy resets.
        """
        self.training_buffer.reset_local_buffers()
        
        for agent_id in self.cumulative_rewards:
            self.cumulative_rewards[agent_id] = 0
        for agent_id in self.episode_steps:
            self.episode_steps[agent_id] = 0
            
        if self.use_curiosity:
            for agent_id in self.intrinsic_rewards:
                self.intrinsic_rewards[agent_id] = 0

    def is_ready_update(self):
        """
        Returns whether or not the trainer has enough elements to run update model
        
        :return: 
            A boolean corresponding to whether or not update_model() can be run
        """
        size_of_buffer = len(self.training_buffer.update_buffer['actions'])
        return size_of_buffer > max(int(self.trainer_parameters['buffer_size'] / self.policy.sequence_length), 1)

    def update_policy(self):
        """
        Uses demonstration_buffer to update the policy.
        """
        n_sequences = max(int(self.trainer_parameters['batch_size'] / self.policy.sequence_length), 1)
        value_total, policy_total, forward_total, inverse_total = [], [], [], []
        advantages = self.training_buffer.update_buffer['advantages'].get_batch()
        
        self.training_buffer.update_buffer['advantages'].set(
            (advantages - advantages.mean()) / (advantages.std() + 1e-10))
        
        num_epoch = self.trainer_parameters['num_epoch']
        
        for k in range(num_epoch):
            self.training_buffer.update_buffer.shuffle()
            buffer = self.training_buffer.update_buffer
            
            for l in range(len(self.training_buffer.update_buffer['actions']) // n_sequences):
                start = l * n_sequences
                end = (l + 1) * n_sequences
                run_out = self.policy.update(buffer.make_mini_batch(start, end), n_sequences)
                value_total.append(run_out['value_loss'])
                policy_total.append(np.abs(run_out['policy_loss']))
                if self.use_curiosity:
                    inverse_total.append(run_out['inverse_loss'])
                    forward_total.append(run_out['forward_loss'])
                    
        self.stats['Losses/Value Loss'].append(np.mean(value_total))
        self.stats['Losses/Policy Loss'].append(np.mean(policy_total))
        
        if self.use_curiosity:
            self.stats['Losses/Forward Loss'].append(np.mean(forward_total))
            self.stats['Losses/Inverse Loss'].append(np.mean(inverse_total))
            
        self.training_buffer.reset_update_buffer()