def train_agent(train_params, train_env_params, eval_env_params, obs_params):
# Environment parameters
n_agents = train_env_params.n_agents
x_dim = train_env_params.x_dim
y_dim = train_env_params.y_dim
n_cities = train_env_params.n_cities
max_rails_between_cities = train_env_params.max_rails_between_cities
max_rails_in_city = train_env_params.max_rails_in_city
seed = train_env_params.seed
# Unique ID for this training
now = datetime.now()
training_id = now.strftime('%y%m%d%H%M%S')
# Observation parameters
observation_tree_depth = obs_params.observation_tree_depth
observation_radius = obs_params.observation_radius
observation_max_path_depth = obs_params.observation_max_path_depth
# Training parameters
eps_start = train_params.eps_start
eps_end = train_params.eps_end
eps_decay = train_params.eps_decay
n_episodes = train_params.n_episodes
checkpoint_interval = train_params.checkpoint_interval
n_eval_episodes = train_params.n_evaluation_episodes
restore_replay_buffer = train_params.restore_replay_buffer
save_replay_buffer = train_params.save_replay_buffer
# Set the seeds
random.seed(seed)
np.random.seed(seed)
# Observation builder
predictor = ShortestPathPredictorForRailEnv(observation_max_path_depth)
tree_observation = TreeObsForRailEnv(max_depth=observation_tree_depth,
predictor=predictor)
# Setup the environments
train_env = create_rail_env(train_env_params, tree_observation)
train_env.reset(regenerate_schedule=True, regenerate_rail=True)
eval_env = create_rail_env(eval_env_params, tree_observation)
eval_env.reset(regenerate_schedule=True, regenerate_rail=True)
# Setup renderer
if train_params.render:
env_renderer = RenderTool(train_env, gl="PGL")
# Calculate the state size given the depth of the tree observation and the number of features
n_features_per_node = train_env.obs_builder.observation_dim
n_nodes = sum([np.power(4, i) for i in range(observation_tree_depth + 1)])
state_size = n_features_per_node * n_nodes
# The action space of flatland is 5 discrete actions
action_size = 5
# Max number of steps per episode
# This is the official formula used during evaluations
# See details in flatland.envs.schedule_generators.sparse_schedule_generator
# max_steps = int(4 * 2 * (env.height + env.width + (n_agents / n_cities)))
max_steps = train_env._max_episode_steps
action_count = [0] * action_size
action_dict = dict()
agent_obs = [None] * n_agents
agent_prev_obs = [None] * n_agents
agent_prev_action = [2] * n_agents
update_values = [False] * n_agents
# Smoothed values used as target for hyperparameter tuning
smoothed_normalized_score = -1.0
smoothed_eval_normalized_score = -1.0
smoothed_completion = 0.0
smoothed_eval_completion = 0.0
# Double Dueling DQN policy
policy = DDDQNPolicy(state_size, action_size, train_params)
# Loads existing replay buffer
if restore_replay_buffer:
try:
policy.load_replay_buffer(restore_replay_buffer)
policy.test()
except RuntimeError as e:
print(
"\nš Could't load replay buffer, were the experiences generated using the same tree depth?"
)
print(e)
exit(1)
print("\nš¾ Replay buffer status: {}/{} experiences".format(
len(policy.memory.memory), train_params.buffer_size))
hdd = psutil.disk_usage('/')
if save_replay_buffer and (hdd.free / (2**30)) < 500.0:
print(
"ā ļø Careful! Saving replay buffers will quickly consume a lot of disk space. You have {:.2f}gb left."
.format(hdd.free / (2**30)))
# TensorBoard writer
writer = SummaryWriter()
writer.add_hparams(vars(train_params), {})
writer.add_hparams(vars(train_env_params), {})
writer.add_hparams(vars(obs_params), {})
training_timer = Timer()
training_timer.start()
print(
"\nš Training {} trains on {}x{} grid for {} episodes, evaluating on {} episodes every {} episodes. Training id '{}'.\n"
.format(train_env.get_num_agents(), x_dim, y_dim, n_episodes,
n_eval_episodes, checkpoint_interval, training_id))
for episode_idx in range(n_episodes + 1):
step_timer = Timer()
reset_timer = Timer()
learn_timer = Timer()
preproc_timer = Timer()
inference_timer = Timer()
# Reset environment
reset_timer.start()
obs, info = train_env.reset(regenerate_rail=True,
regenerate_schedule=True)
reset_timer.end()
if train_params.render:
env_renderer.set_new_rail()
score = 0
nb_steps = 0
actions_taken = []
# Build initial agent-specific observations
for agent in train_env.get_agent_handles():
if obs[agent]:
agent_obs[agent] = normalize_observation(
obs[agent],
observation_tree_depth,
observation_radius=observation_radius)
agent_prev_obs[agent] = agent_obs[agent].copy()
# Run episode
for step in range(max_steps - 1):
inference_timer.start()
for agent in train_env.get_agent_handles():
if info['action_required'][agent]:
update_values[agent] = True
action = policy.act(agent_obs[agent], eps=eps_start)
action_count[action] += 1
actions_taken.append(action)
else:
# An action is not required if the train hasn't joined the railway network,
# if it already reached its target, or if is currently malfunctioning.
update_values[agent] = False
action = 0
action_dict.update({agent: action})
inference_timer.end()
# Environment step
step_timer.start()
next_obs, all_rewards, done, info = train_env.step(action_dict)
step_timer.end()
# Render an episode at some interval
if train_params.render and episode_idx % checkpoint_interval == 0:
env_renderer.render_env(show=True,
frames=False,
show_observations=False,
show_predictions=False)
# Update replay buffer and train agent
for agent in train_env.get_agent_handles():
if update_values[agent] or done['__all__']:
# Only learn from timesteps where somethings happened
learn_timer.start()
policy.step(agent_prev_obs[agent],
agent_prev_action[agent], all_rewards[agent],
agent_obs[agent], done[agent])
learn_timer.end()
agent_prev_obs[agent] = agent_obs[agent].copy()
agent_prev_action[agent] = action_dict[agent]
# Preprocess the new observations
if next_obs[agent]:
preproc_timer.start()
agent_obs[agent] = normalize_observation(
next_obs[agent],
observation_tree_depth,
observation_radius=observation_radius)
preproc_timer.end()
score += all_rewards[agent]
nb_steps = step
if done['__all__']:
break
# Epsilon decay
eps_start = max(eps_end, eps_decay * eps_start)
# Collect information about training
tasks_finished = sum(done[idx]
for idx in train_env.get_agent_handles())
completion = tasks_finished / max(1, train_env.get_num_agents())
normalized_score = score / (max_steps * train_env.get_num_agents())
action_probs = action_count / np.sum(action_count)
action_count = [1] * action_size
smoothing = 0.99
smoothed_normalized_score = smoothed_normalized_score * smoothing + normalized_score * (
1.0 - smoothing)
smoothed_completion = smoothed_completion * smoothing + completion * (
1.0 - smoothing)
# Print logs
if episode_idx % checkpoint_interval == 0:
torch.save(
policy.qnetwork_local, './checkpoints/' + training_id + '-' +
str(episode_idx) + '.pth')
if save_replay_buffer:
policy.save_replay_buffer('./replay_buffers/' + training_id +
'-' + str(episode_idx) + '.pkl')
if train_params.render:
env_renderer.close_window()
print('\rš Episode {}'
'\t š Score: {:.3f}'
' Avg: {:.3f}'
'\t šÆ Done: {:.2f}%'
' Avg: {:.2f}%'
'\t š² Epsilon: {:.3f} '
'\t š Action Probs: {}'.format(episode_idx, normalized_score,
smoothed_normalized_score,
100 * completion,
100 * smoothed_completion,
eps_start,
format_action_prob(action_probs)),
end=" ")
# Evaluate policy and log results at some interval
if episode_idx % checkpoint_interval == 0 and n_eval_episodes > 0:
scores, completions, nb_steps_eval = eval_policy(
eval_env, policy, train_params, obs_params)
writer.add_scalar("evaluation/scores_min", np.min(scores),
episode_idx)
writer.add_scalar("evaluation/scores_max", np.max(scores),
episode_idx)
writer.add_scalar("evaluation/scores_mean", np.mean(scores),
episode_idx)
writer.add_scalar("evaluation/scores_std", np.std(scores),
episode_idx)
writer.add_histogram("evaluation/scores", np.array(scores),
episode_idx)
writer.add_scalar("evaluation/completions_min",
np.min(completions), episode_idx)
writer.add_scalar("evaluation/completions_max",
np.max(completions), episode_idx)
writer.add_scalar("evaluation/completions_mean",
np.mean(completions), episode_idx)
writer.add_scalar("evaluation/completions_std",
np.std(completions), episode_idx)
writer.add_histogram("evaluation/completions",
np.array(completions), episode_idx)
writer.add_scalar("evaluation/nb_steps_min", np.min(nb_steps_eval),
episode_idx)
writer.add_scalar("evaluation/nb_steps_max", np.max(nb_steps_eval),
episode_idx)
writer.add_scalar("evaluation/nb_steps_mean",
np.mean(nb_steps_eval), episode_idx)
writer.add_scalar("evaluation/nb_steps_std", np.std(nb_steps_eval),
episode_idx)
writer.add_histogram("evaluation/nb_steps",
np.array(nb_steps_eval), episode_idx)
smoothing = 0.9
smoothed_eval_normalized_score = smoothed_eval_normalized_score * smoothing + np.mean(
scores) * (1.0 - smoothing)
smoothed_eval_completion = smoothed_eval_completion * smoothing + np.mean(
completions) * (1.0 - smoothing)
writer.add_scalar("evaluation/smoothed_score",
smoothed_eval_normalized_score, episode_idx)
writer.add_scalar("evaluation/smoothed_completion",
smoothed_eval_completion, episode_idx)
# Save logs to tensorboard
writer.add_scalar("training/score", normalized_score, episode_idx)
writer.add_scalar("training/smoothed_score", smoothed_normalized_score,
episode_idx)
writer.add_scalar("training/completion", np.mean(completion),
episode_idx)
writer.add_scalar("training/smoothed_completion",
np.mean(smoothed_completion), episode_idx)
writer.add_scalar("training/nb_steps", nb_steps, episode_idx)
writer.add_histogram("actions/distribution", np.array(actions_taken),
episode_idx)
writer.add_scalar("actions/nothing",
action_probs[RailEnvActions.DO_NOTHING], episode_idx)
writer.add_scalar("actions/left",
action_probs[RailEnvActions.MOVE_LEFT], episode_idx)
writer.add_scalar("actions/forward",
action_probs[RailEnvActions.MOVE_FORWARD],
episode_idx)
writer.add_scalar("actions/right",
action_probs[RailEnvActions.MOVE_RIGHT], episode_idx)
writer.add_scalar("actions/stop",
action_probs[RailEnvActions.STOP_MOVING],
episode_idx)
writer.add_scalar("training/epsilon", eps_start, episode_idx)
writer.add_scalar("training/buffer_size", len(policy.memory),
episode_idx)
writer.add_scalar("training/loss", policy.loss, episode_idx)
writer.add_scalar("timer/reset", reset_timer.get(), episode_idx)
writer.add_scalar("timer/step", step_timer.get(), episode_idx)
writer.add_scalar("timer/learn", learn_timer.get(), episode_idx)
writer.add_scalar("timer/preproc", preproc_timer.get(), episode_idx)
writer.add_scalar("timer/total", training_timer.get_current(),
episode_idx)
class MultiDecisionAgent(LearningPolicy):
def __init__(self, state_size, action_size, in_parameters=None):
print(">> MultiDecisionAgent")
super(MultiDecisionAgent, self).__init__()
self.state_size = state_size
self.action_size = action_size
self.in_parameters = in_parameters
self.memory = DummyMemory()
self.loss = 0
self.ppo_policy = PPOPolicy(state_size,
action_size,
use_replay_buffer=False,
in_parameters=in_parameters)
self.dddqn_policy = DDDQNPolicy(state_size, action_size, in_parameters)
self.policy_selector = PPOPolicy(state_size, 2)
def step(self, handle, state, action, reward, next_state, done):
self.ppo_policy.step(handle, state, action, reward, next_state, done)
self.dddqn_policy.step(handle, state, action, reward, next_state, done)
select = self.policy_selector.act(handle, state, 0.0)
self.policy_selector.step(handle, state, select, reward, next_state,
done)
def act(self, handle, state, eps=0.):
select = self.policy_selector.act(handle, state, eps)
if select == 0:
return self.dddqn_policy.act(handle, state, eps)
return self.policy_selector.act(handle, state, eps)
def save(self, filename):
self.ppo_policy.save(filename)
self.dddqn_policy.save(filename)
self.policy_selector.save(filename)
def load(self, filename):
self.ppo_policy.load(filename)
self.dddqn_policy.load(filename)
self.policy_selector.load(filename)
def start_step(self, train):
self.ppo_policy.start_step(train)
self.dddqn_policy.start_step(train)
self.policy_selector.start_step(train)
def end_step(self, train):
self.ppo_policy.end_step(train)
self.dddqn_policy.end_step(train)
self.policy_selector.end_step(train)
def start_episode(self, train):
self.ppo_policy.start_episode(train)
self.dddqn_policy.start_episode(train)
self.policy_selector.start_episode(train)
def end_episode(self, train):
self.ppo_policy.end_episode(train)
self.dddqn_policy.end_episode(train)
self.policy_selector.end_episode(train)
def load_replay_buffer(self, filename):
self.ppo_policy.load_replay_buffer(filename)
self.dddqn_policy.load_replay_buffer(filename)
self.policy_selector.load_replay_buffer(filename)
def test(self):
self.ppo_policy.test()
self.dddqn_policy.test()
self.policy_selector.test()
def reset(self, env: RailEnv):
self.ppo_policy.reset(env)
self.dddqn_policy.reset(env)
self.policy_selector.reset(env)
def clone(self):
multi_descision_agent = MultiDecisionAgent(self.state_size,
self.action_size,
self.in_parameters)
multi_descision_agent.ppo_policy = self.ppo_policy.clone()
multi_descision_agent.dddqn_policy = self.dddqn_policy.clone()
multi_descision_agent.policy_selector = self.policy_selector.clone()
return multi_descision_agent