class AtariGame(Game):
def __init__(self,
rom_path=_default_rom_path,
frame_skip=4, history_length=4,
resize_mode='scale', resized_rows=84, resized_cols=84, crop_offset=8,
display_screen=False, max_null_op=30,
replay_memory_size=1000000,
replay_start_size=100,
death_end_episode=True):
super(AtariGame, self).__init__()
self.rng = get_numpy_rng()
self.ale = ale_load_from_rom(rom_path=rom_path, display_screen=display_screen)
self.start_lives = self.ale.lives()
self.action_set = self.ale.getMinimalActionSet()
self.resize_mode = resize_mode
self.resized_rows = resized_rows
self.resized_cols = resized_cols
self.crop_offset = crop_offset
self.frame_skip = frame_skip
self.history_length = history_length
self.max_null_op = max_null_op
self.death_end_episode = death_end_episode
self.screen_buffer_length = 2
self.screen_buffer = numpy.empty((self.screen_buffer_length,
self.ale.getScreenDims()[1], self.ale.getScreenDims()[0]),
dtype='uint8')
self.replay_memory = ReplayMemory(state_dim=(resized_rows, resized_cols),
history_length=history_length,
memory_size=replay_memory_size,
replay_start_size=replay_start_size)
self.start()
def start(self):
self.ale.reset_game()
null_op_num = self.rng.randint(self.screen_buffer_length,
max(self.max_null_op + 1, self.screen_buffer_length + 1))
for i in range(null_op_num):
self.ale.act(0)
self.ale.getScreenGrayscale(self.screen_buffer[i % self.screen_buffer_length, :, :])
self.total_reward = 0
self.episode_reward = 0
self.episode_step = 0
self.max_episode_step = DEFAULT_MAX_EPISODE_STEP
self.start_lives = self.ale.lives()
def force_restart(self):
self.start()
self.replay_memory.clear()
def begin_episode(self, max_episode_step=DEFAULT_MAX_EPISODE_STEP):
"""
Begin an episode of a game instance. We can play the game for a maximum of
`max_episode_step` and after that, we are forced to restart
"""
if self.episode_step > self.max_episode_step or self.ale.game_over():
self.start()
else:
for i in range(self.screen_buffer_length):
self.ale.act(0)
self.ale.getScreenGrayscale(self.screen_buffer[i % self.screen_buffer_length, :, :])
self.max_episode_step = max_episode_step
self.start_lives = self.ale.lives()
self.episode_reward = 0
self.episode_step = 0
@property
def episode_terminate(self):
termination_flag = self.ale.game_over() or self.episode_step >= self.max_episode_step
if self.death_end_episode:
return (self.ale.lives() < self.start_lives) or termination_flag
else:
return termination_flag
@property
def state_enabled(self):
return self.replay_memory.size >= self.replay_memory.history_length
def get_observation(self):
image = self.screen_buffer.max(axis=0)
if 'crop' == self.resize_mode:
original_rows, original_cols = image.shape
new_resized_rows = int(round(
float(original_rows) * self.resized_cols / original_cols))
resized = cv2.resize(image, (self.resized_cols, new_resized_rows),
interpolation=cv2.INTER_LINEAR)
crop_y_cutoff = new_resized_rows - self.crop_offset - self.resized_rows
img = resized[crop_y_cutoff:
crop_y_cutoff + self.resized_rows, :]
return img
else:
return cv2.resize(image, (self.resized_cols, self.resized_rows),
interpolation=cv2.INTER_LINEAR)
def play(self, a):
assert not self.episode_terminate,\
"Warning, the episode seems to have terminated. " \
"We need to call either game.begin_episode(max_episode_step) to continue a new " \
"episode or game.start() to force restart."
self.episode_step += 1
reward = 0.0
action = self.action_set[a]
for i in range(self.frame_skip):
reward += self.ale.act(action)
self.ale.getScreenGrayscale(self.screen_buffer[i % self.screen_buffer_length, :, :])
self.total_reward += reward
self.episode_reward += reward
ob = self.get_observation()
terminate_flag = self.episode_terminate
self.replay_memory.append(ob, a, numpy.clip(reward, -1, 1), terminate_flag)
return reward, terminate_flag
class Trainer():
def __init__(self,
env,
network,
update_timestep=2000,
batch_size=512,
gamma=0.99,
epsilon=0.2,
c1=0.5,
c2=0.01,
lr=0.01,
weight_decay=0.0,
min_std=0.1):
self.device = torch.device(
"cuda:0" if torch.cuda.is_available() else "cpu")
self.memory = ReplayMemory(update_timestep)
self.env = env
self.policy_net = network
self.policy_net.to(self.device)
self.gamma = gamma
self.epsilon = epsilon
self.c1 = c1
self.c2 = c2
self.update_timestep = update_timestep
self.min_std = min_std
self.batch_size = batch_size
self.optimizer = torch.optim.Adam(self.policy_net.parameters(),
lr=lr,
weight_decay=weight_decay,
betas=(0.9, 0.999))
self.mse = nn.MSELoss()
self.reward_log = []
self.loss_log = []
self.time_log = []
self.num_updates = 0
def ppo_update(self, num_epochs):
#TODO: Fix wrong calculation of q_values
self.num_updates += 1
experience = self.memory.sample()
#dimension of states need to be squeezed to not cause trouble in the
#log_probs computation in the evaluate function.
exp_states = torch.stack(experience.state).squeeze().float()
exp_actions = torch.stack(experience.action)
exp_rewards = experience.reward
exp_dones = experience.done
exp_log_probs = torch.stack(experience.log_prob).squeeze()
#calculate q-values
q_values = []
discounted_reward = 0
for reward, done in zip(reversed(exp_rewards), reversed(exp_dones)):
if done:
discounted_reward = 0
discounted_reward = reward + (self.gamma * discounted_reward)
q_values.insert(0, discounted_reward)
q_values = torch.tensor(q_values, device=self.device)
q_values = (q_values - q_values.mean()) / (q_values.std() + 1e-5)
dataset = TensorDataset(exp_states, exp_actions, exp_log_probs,
q_values)
trainloader = DataLoader(dataset,
batch_size=self.batch_size,
shuffle=False)
train_loss = 0
num_iterations = 0
for _ in range(num_epochs):
for state_batch, action_batch, log_probs_batch, q_value_batch in trainloader:
#evaluate previous states
state_values, log_probs, dist_entropy = self.policy_net.evaluate(
state_batch, action_batch)
# Calculate ratio (pi_theta / pi_theta__old):
ratios = torch.exp(log_probs - log_probs_batch.detach())
# Calculate Surrogate Loss:
advantages = q_value_batch - state_values.detach()
surr1 = ratios * advantages
surr2 = torch.clamp(ratios, 1 - self.epsilon,
1 + self.epsilon) * advantages
actor_loss = torch.min(surr1, surr2)
critic_loss = self.mse(state_values, q_value_batch)
# - because of gradient ascent
loss = -actor_loss + self.c1 * critic_loss - self.c2 * dist_entropy
train_loss += loss.mean()
# take gradient step
self.optimizer.zero_grad()
loss.mean().backward()
self.optimizer.step()
num_iterations += 1
self.loss_log.append(train_loss / num_iterations)
def train(self, num_episodes, num_epochs, max_timesteps, render=False):
timestep = 0
for i_episode in range(1, num_episodes + 1):
state = self.env.reset()
running_reward = 0
for i_timestep in range(max_timesteps):
timestep += 1
# compute action
state = torch.FloatTensor(state.reshape(1, -1)).to(self.device)
prev_state = state
with torch.no_grad():
action, action_log_prob = self.policy_net.act(state)
state, reward, done, _ = self.env.step(action.cpu().numpy())
running_reward += reward
transition = Transition(prev_state, action, reward,
action_log_prob, done)
self.memory.push(transition)
#Update policy network
if timestep % self.update_timestep == 0:
self.ppo_update(num_epochs)
print("Policy updated")
self.memory.clear()
timestep = 0
if render:
env.render()
if done:
break
print('Episode {} Done, \t length: {} \t reward: {}'.format(
i_episode, i_timestep, running_reward))
self.reward_log.append(int(running_reward))
self.time_log.append(i_timestep)
def plot_rewards(self):
plt.plot(self.reward_log)
def plot_loss(self):
plt.plot(self.loss_log)
class AtariGame(Game):
def __init__(self,
rom_path=_default_rom_path,
frame_skip=4,
history_length=4,
resize_mode='clip',
resized_rows=84,
resized_cols=84,
crop_offset=8,
display_screen=False,
max_null_op=30,
replay_memory_size=1000000,
replay_start_size=100,
death_end_episode=True):
super(AtariGame, self).__init__()
self.rng = get_numpy_rng()
self.ale = ale_load_from_rom(rom_path=rom_path,
display_screen=display_screen)
self.start_lives = self.ale.lives()
self.action_set = self.ale.getMinimalActionSet()
self.resize_mode = resize_mode
self.resized_rows = resized_rows
self.resized_cols = resized_cols
self.crop_offset = crop_offset
self.frame_skip = frame_skip
self.history_length = history_length
self.max_null_op = max_null_op
self.death_end_episode = death_end_episode
self.screen_buffer_length = 2
self.screen_buffer = numpy.empty(
(self.screen_buffer_length, self.ale.getScreenDims()[1],
self.ale.getScreenDims()[0]),
dtype='uint8')
self.replay_memory = ReplayMemory(state_dim=(resized_rows,
resized_cols),
history_length=history_length,
memory_size=replay_memory_size,
replay_start_size=replay_start_size)
self.start()
def start(self):
self.ale.reset_game()
null_op_num = self.rng.randint(
self.screen_buffer_length,
max(self.max_null_op + 1, self.screen_buffer_length + 1))
for i in range(null_op_num):
self.ale.act(0)
self.ale.getScreenGrayscale(
self.screen_buffer[i % self.screen_buffer_length, :, :])
self.total_reward = 0
self.episode_reward = 0
self.episode_step = 0
self.max_episode_step = DEFAULT_MAX_EPISODE_STEP
self.start_lives = self.ale.lives()
def force_restart(self):
self.start()
self.replay_memory.clear()
def begin_episode(self, max_episode_step=DEFAULT_MAX_EPISODE_STEP):
"""
Begin an episode of a game instance. We can play the game for a maximum of
`max_episode_step` and after that, we are forced to restart
"""
if self.episode_step > self.max_episode_step or self.ale.game_over():
self.start()
else:
for i in range(self.screen_buffer_length):
self.ale.act(0)
self.ale.getScreenGrayscale(
self.screen_buffer[i % self.screen_buffer_length, :, :])
self.max_episode_step = max_episode_step
self.start_lives = self.ale.lives()
self.episode_reward = 0
self.episode_step = 0
@property
def episode_terminate(self):
termination_flag = self.ale.game_over(
) or self.episode_step >= self.max_episode_step
if self.death_end_episode:
return (self.ale.lives() < self.start_lives) or termination_flag
else:
return termination_flag
@property
def state_enabled(self):
return self.replay_memory.size >= self.replay_memory.history_length
def get_observation(self):
image = self.screen_buffer.max(axis=0)
if 'crop' == self.resize_mode:
original_rows, original_cols = image.shape
new_resized_rows = int(
round(
float(original_rows) * self.resized_cols / original_cols))
resized = cv2.resize(image, (self.resized_cols, new_resized_rows),
interpolation=cv2.INTER_LINEAR)
crop_y_cutoff = new_resized_rows - self.crop_offset - self.resized_rows
img = resized[crop_y_cutoff:crop_y_cutoff + self.resized_rows, :]
return img
else:
# plt.imshow(image, cmap='gray')
# plt.show()
return cv2.resize(image, (self.resized_cols, self.resized_rows),
interpolation=cv2.INTER_LINEAR)
def play(self, a):
assert not self.episode_terminate,\
"Warning, the episode seems to have terminated. " \
"We need to call either game.begin_episode(max_episode_step) to continue a new " \
"episode or game.start() to force restart."
self.episode_step += 1
reward = 0.0
action = self.action_set[int(a)]
for i in range(self.frame_skip):
reward += self.ale.act(action)
self.ale.getScreenGrayscale(
self.screen_buffer[i % self.screen_buffer_length, :, :])
self.total_reward += reward
self.episode_reward += reward
ob = self.get_observation()
# plt.imshow(ob, cmap="gray")
# plt.show()
terminate_flag = self.episode_terminate
self.replay_memory.append(ob, a, numpy.clip(reward, -1, 1),
terminate_flag)
return reward, terminate_flag
