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172 行
9.0 KiB
172 行
9.0 KiB
import numpy as np
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import tensorflow as tf
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from ppo.history import *
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class Trainer(object):
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def __init__(self, ppo_model, sess, info, is_continuous, use_observations, use_states):
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"""
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Responsible for collecting experinces and training PPO model.
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:param ppo_model: Tensorflow graph defining model.
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:param sess: Tensorflow session.
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:param info: Environment BrainInfo object.
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:param is_continuous: Whether action-space is continuous.
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:param use_observations: Whether agent takes image observations.
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"""
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self.model = ppo_model
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self.sess = sess
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stats = {'cumulative_reward': [], 'episode_length': [], 'value_estimate': [],
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'entropy': [], 'value_loss': [], 'policy_loss': [], 'learning_rate': []}
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self.stats = stats
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self.training_buffer = vectorize_history(empty_local_history({}))
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self.history_dict = empty_all_history(info)
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self.is_continuous = is_continuous
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self.use_observations = use_observations
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self.use_states = use_states
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def take_action(self, info, env, brain_name):
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"""
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Decides actions given state/observation information, and takes them in environment.
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:param info: Current BrainInfo from environment.
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:param env: Environment to take actions in.
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:param brain_name: Name of brain we are learning model for.
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:return: BrainInfo corresponding to new environment state.
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"""
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epsi = None
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feed_dict = {self.model.batch_size: len(info.states)}
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if self.is_continuous:
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epsi = np.random.randn(len(info.states), env.brains[brain_name].action_space_size)
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feed_dict[self.model.epsilon] = epsi
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if self.use_observations:
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feed_dict[self.model.observation_in] = np.vstack(info.observations)
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if self.use_states:
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feed_dict[self.model.state_in] = info.states
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actions, a_dist, value, ent, learn_rate = self.sess.run([self.model.output, self.model.probs,
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self.model.value, self.model.entropy,
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self.model.learning_rate],
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feed_dict=feed_dict)
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self.stats['value_estimate'].append(value)
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self.stats['entropy'].append(ent)
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self.stats['learning_rate'].append(learn_rate)
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new_info = env.step(actions, value={brain_name: value})[brain_name]
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self.add_experiences(info, new_info, epsi, actions, a_dist, value)
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return new_info
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def add_experiences(self, info, next_info, epsi, actions, a_dist, value):
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"""
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Adds experiences to each agent's experience history.
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:param info: Current BrainInfo.
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:param next_info: Next BrainInfo.
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:param epsi: Epsilon value (for continuous control)
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:param actions: Chosen actions.
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:param a_dist: Action probabilities.
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:param value: Value estimates.
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"""
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for (agent, history) in self.history_dict.items():
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if agent in info.agents:
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idx = info.agents.index(agent)
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if not info.local_done[idx]:
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if self.use_observations:
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history['observations'].append(info.observations[idx])
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if self.use_states:
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history['states'].append(info.states[idx])
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if self.is_continuous:
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history['epsilons'].append(epsi[idx])
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history['actions'].append(actions[idx])
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history['rewards'].append(next_info.rewards[idx])
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history['action_probs'].append(a_dist[idx])
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history['value_estimates'].append(value[idx][0])
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history['cumulative_reward'] += next_info.rewards[idx]
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history['episode_steps'] += 1
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def process_experiences(self, info, time_horizon, gamma, lambd):
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"""
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Checks agent histories for processing condition, and processes them as necessary.
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Processing involves calculating value and advantage targets for model updating step.
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:param info: Current BrainInfo
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:param time_horizon: Max steps for individual agent history before processing.
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:param gamma: Discount factor.
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:param lambd: GAE factor.
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"""
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for l in range(len(info.agents)):
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if (info.local_done[l] or len(self.history_dict[info.agents[l]]['actions']) > time_horizon) and len(
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self.history_dict[info.agents[l]]['actions']) > 0:
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if info.local_done[l]:
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value_next = 0.0
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else:
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feed_dict = {self.model.batch_size: len(info.states)}
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if self.use_observations:
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feed_dict[self.model.observation_in] = np.vstack(info.observations)
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if self.use_states:
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feed_dict[self.model.state_in] = info.states
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value_next = self.sess.run(self.model.value, feed_dict)[l]
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history = vectorize_history(self.history_dict[info.agents[l]])
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history['advantages'] = get_gae(rewards=history['rewards'],
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value_estimates=history['value_estimates'],
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value_next=value_next, gamma=gamma, lambd=lambd)
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history['discounted_returns'] = history['advantages'] + history['value_estimates']
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if len(self.training_buffer['actions']) > 0:
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append_history(global_buffer=self.training_buffer, local_buffer=history)
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else:
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set_history(global_buffer=self.training_buffer, local_buffer=history)
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self.history_dict[info.agents[l]] = empty_local_history(self.history_dict[info.agents[l]])
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if info.local_done[l]:
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self.stats['cumulative_reward'].append(history['cumulative_reward'])
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self.stats['episode_length'].append(history['episode_steps'])
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history['cumulative_reward'] = 0
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history['episode_steps'] = 0
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def update_model(self, batch_size, num_epoch):
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"""
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Uses training_buffer to update model.
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:param batch_size: Size of each mini-batch update.
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:param num_epoch: How many passes through data to update model for.
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"""
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total_v, total_p = 0, 0
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advantages = self.training_buffer['advantages']
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self.training_buffer['advantages'] = (advantages - advantages.mean()) / advantages.std()
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for k in range(num_epoch):
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training_buffer = shuffle_buffer(self.training_buffer)
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for l in range(len(training_buffer['actions']) // batch_size):
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start = l * batch_size
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end = (l + 1) * batch_size
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feed_dict = {self.model.returns_holder: training_buffer['discounted_returns'][start:end],
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self.model.advantage: np.vstack(training_buffer['advantages'][start:end]),
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self.model.old_probs: np.vstack(training_buffer['action_probs'][start:end])}
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if self.is_continuous:
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feed_dict[self.model.epsilon] = np.vstack(training_buffer['epsilons'][start:end])
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else:
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feed_dict[self.model.action_holder] = np.hstack(training_buffer['actions'][start:end])
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if self.use_states:
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feed_dict[self.model.state_in] = np.vstack(training_buffer['states'][start:end])
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if self.use_observations:
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feed_dict[self.model.observation_in] = np.vstack(training_buffer['observations'][start:end])
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v_loss, p_loss, _ = self.sess.run([self.model.value_loss, self.model.policy_loss,
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self.model.update_batch], feed_dict=feed_dict)
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total_v += v_loss
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total_p += p_loss
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self.stats['value_loss'].append(total_v)
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self.stats['policy_loss'].append(total_p)
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self.training_buffer = vectorize_history(empty_local_history({}))
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for key in self.history_dict:
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self.history_dict[key] = empty_local_history(self.history_dict[key])
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def write_summary(self, summary_writer, steps):
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"""
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Saves training statistics to Tensorboard.
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:param summary_writer: writer associated with Tensorflow session.
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:param steps: Number of environment steps in training process.
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"""
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print("Mean Reward: {0}".format(np.mean(self.stats['cumulative_reward'])))
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summary = tf.Summary()
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for key in self.stats:
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if len(self.stats[key]) > 0:
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stat_mean = float(np.mean(self.stats[key]))
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summary.value.add(tag='Info/{}'.format(key), simple_value=stat_mean)
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self.stats[key] = []
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summary_writer.add_summary(summary, steps)
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summary_writer.flush()
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