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coach/agents/policy_optimization_agent.py
Roman Dobosz 1b095aeeca Cleanup imports.
Till now, most of the modules were importing all of the module objects
(variables, classes, functions, other imports) into module namespace,
which potentially could (and was) cause of unintentional use of class or
methods, which was indirect imported.

With this patch, all the star imports were substituted with top-level
module, which provides desired class or function.

Besides, all imports where sorted (where possible) in a way pep8[1]
suggests - first are imports from standard library, than goes third
party imports (like numpy, tensorflow etc) and finally coach modules.
All of those sections are separated by one empty line.

[1] https://www.python.org/dev/peps/pep-0008/#imports
2018-04-13 09:58:40 +02:00

129 lines
5.4 KiB
Python

#
# Copyright (c) 2017 Intel Corporation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import collections
import numpy as np
from agents import agent
from architectures import network_wrapper as nw
import logger
import utils
class PolicyGradientRescaler(utils.Enum):
TOTAL_RETURN = 0
FUTURE_RETURN = 1
FUTURE_RETURN_NORMALIZED_BY_EPISODE = 2
FUTURE_RETURN_NORMALIZED_BY_TIMESTEP = 3 # baselined
Q_VALUE = 4
A_VALUE = 5
TD_RESIDUAL = 6
DISCOUNTED_TD_RESIDUAL = 7
GAE = 8
class PolicyOptimizationAgent(agent.Agent):
def __init__(self, env, tuning_parameters, replicated_device=None, thread_id=0, create_target_network=False):
agent.Agent.__init__(self, env, tuning_parameters, replicated_device, thread_id)
self.main_network = nw.NetworkWrapper(tuning_parameters, create_target_network, self.has_global, 'main',
self.replicated_device, self.worker_device)
self.networks.append(self.main_network)
self.policy_gradient_rescaler = PolicyGradientRescaler().get(self.tp.agent.policy_gradient_rescaler)
# statistics for variance reduction
self.last_gradient_update_step_idx = 0
self.max_episode_length = 100000
self.mean_return_over_multiple_episodes = np.zeros(self.max_episode_length)
self.num_episodes_where_step_has_been_seen = np.zeros(self.max_episode_length)
self.entropy = utils.Signal('Entropy')
self.signals.append(self.entropy)
self.reset_game(do_not_reset_env=True)
def log_to_screen(self, phase):
# log to screen
if self.current_episode > 0:
logger.screen.log_dict(
collections.OrderedDict([
("Worker", self.task_id),
("Episode", self.current_episode),
("total reward", self.total_reward_in_current_episode),
("steps", self.total_steps_counter),
("training iteration", self.training_iteration)
]),
prefix=phase
)
def update_episode_statistics(self, episode):
episode_discounted_returns = []
for i in range(episode.length()):
transition = episode.get_transition(i)
episode_discounted_returns.append(transition.total_return)
self.num_episodes_where_step_has_been_seen[i] += 1
self.mean_return_over_multiple_episodes[i] -= self.mean_return_over_multiple_episodes[i] / \
self.num_episodes_where_step_has_been_seen[i]
self.mean_return_over_multiple_episodes[i] += transition.total_return / \
self.num_episodes_where_step_has_been_seen[i]
self.mean_discounted_return = np.mean(episode_discounted_returns)
self.std_discounted_return = np.std(episode_discounted_returns)
def train(self):
if self.memory.length() == 0:
return 0
episode = self.memory.get_episode(0)
# check if we should calculate gradients or skip
episode_ended = self.memory.num_complete_episodes() >= 1
num_steps_passed_since_last_update = episode.length() - self.last_gradient_update_step_idx
is_t_max_steps_passed = num_steps_passed_since_last_update >= self.tp.agent.num_steps_between_gradient_updates
if not (is_t_max_steps_passed or episode_ended):
return 0
total_loss = 0
if num_steps_passed_since_last_update > 0:
# we need to update the returns of the episode until now
episode.update_returns(self.tp.agent.discount)
# get t_max transitions or less if the we got to a terminal state
# will be used for both actor-critic and vanilla PG.
# # In order to get full episodes, Vanilla PG will set the end_idx to a very big value.
transitions = []
start_idx = self.last_gradient_update_step_idx
end_idx = episode.length()
for idx in range(start_idx, end_idx):
transitions.append(episode.get_transition(idx))
self.last_gradient_update_step_idx = end_idx
# update the statistics for the variance reduction techniques
if self.tp.agent.type == 'PolicyGradientsAgent':
self.update_episode_statistics(episode)
# accumulate the gradients and apply them once in every apply_gradients_every_x_episodes episodes
total_loss = self.learn_from_batch(transitions)
if self.current_episode % self.tp.agent.apply_gradients_every_x_episodes == 0:
self.main_network.apply_gradients_and_sync_networks()
# move the pointer to the next episode start and discard the episode. we use it only once
if episode_ended:
self.memory.remove_episode(0)
self.last_gradient_update_step_idx = 0
return total_loss