class OnPolicyTrainer(BaseTrainer):
def __init__(
self,
agent_online,
agent_train,
train_env,
# kwargs comes from config
update_period=1,
normalize_obs=False,
train_obs_normalizer=False,
scale_reward=False,
normalize_reward=False,
train_reward_normalizer=False,
obs_clip=float('inf'),
reward_clip=float('inf'),
warm_up_steps=0,
**kwargs):
"""On-policy trainer
:param agent_online: agent which collects data
:param agent_train: agent which performs train-ops
:param train_env: environment for collecting training data
:param test_env: environment for testing agent once per epoch
:param update_period: number of train-ops after which
online agent loads weights of training agent
:param normalize_obs: if True then observations will be normalized
by running mean and std of collected observations
:param train_obs_normalizer: if True then running mean and std of obs_normalizer
will be updated each environment step
:param scale_reward: if True then reward will be normalized
by running mean and std of collected episodes return
:param normalize_reward: if True then reward will be normalized
by running mean and std of collected rewards
:param train_reward_normalizer: if True then running mean and std of reward_normalizer
will be updated each environment step
:param obs_clip: abs(observation) will be clipped to this value after normalization
:param reward_clip: abs(reward) will be clipped to this value after normalization
:param warm_up_steps: number of steps not to update online agent,
useful to continue training from checkpoint
:param kwargs: test_env and log_dir
"""
super().__init__(**kwargs)
self._agent_online = agent_online # gather rollouts
self._agent_train = agent_train # do train-ops
self._update_online_agent()
# weights of online agent updated once in 'update_period' & at the end of training epoch
self._update_period = update_period
self._warm_up_steps = warm_up_steps
# both environments should:
# vectorized
# reset environment automatically
self._train_env = train_env
# normalizers:
self._obs_normalizer = RunningMeanStd(
obs_clip) if normalize_obs else None
self._train_obs_normalizer = train_obs_normalizer
assert not (normalize_reward and scale_reward), \
'reward may be normalized or scaled, but not both at the same time!'
self._normalize_reward = normalize_reward
self._scale_reward = scale_reward
self._reward_normalizer = RunningMeanStd(reward_clip) \
if normalize_reward or scale_reward else None
self._train_reward_normalizer = train_reward_normalizer
self._gamma = self._agent_train.gamma
# store episode reward, length, return and number for each train environment
self._env_total_reward = np.zeros(train_env.num_envs, dtype=np.float32)
self._env_episode_len = np.zeros(train_env.num_envs, dtype=np.int32)
self._env_discounted_return = np.zeros(train_env.num_envs,
dtype=np.float32)
self._env_episode_number = np.zeros(train_env.num_envs, dtype=np.int32)
def save(self, filename):
state_dict = {'agent': self._agent_train.state_dict()}
if self._obs_normalizer is not None:
state_dict['obs_normalizer'] = self._obs_normalizer.state_dict()
if self._reward_normalizer is not None:
state_dict[
'reward_normalizer'] = self._reward_normalizer.state_dict()
torch.save(state_dict, filename)
def load(self, filename):
checkpoint = torch.load(filename)
self._agent_online.load_state_dict(checkpoint['agent'])
self._agent_train.load_state_dict(checkpoint['agent'])
if 'obs_normalizer' in checkpoint and self._obs_normalizer is not None:
self._obs_normalizer.load_state_dict(checkpoint['obs_normalizer'])
if 'reward_normalizer' in checkpoint and self._reward_normalizer is not None:
self._reward_normalizer.load_state_dict(
checkpoint['reward_normalizer'])
def _act(self, fake_agent, observation, deterministic, **kwargs):
# this method used ONLY inside base class '._test_agent_service()' method
# 'fake_agent' arg is unused to make this method work in BaseTrainer.test_agent_service
observation = self._normalize_observation_fn(observation, False)
return super()._act(self._agent_online, observation, deterministic)
def _normalize_observation_fn(self, observation, training):
if self._obs_normalizer is not None:
if training:
self._obs_normalizer.update(observation)
observation = self._obs_normalizer.normalize(observation)
return observation
def _normalize_reward_fn(self, reward, training):
# 'baselines' version:
if self._scale_reward is not None:
if training:
self._reward_normalizer.update(self._env_discounted_return)
reward = self._reward_normalizer.scale(reward)
# 'my' version:
if self._reward_normalizer is not None:
if training:
self._reward_normalizer.update(reward)
reward = self._reward_normalizer.normalize(reward)
return reward
def _update_running_statistics(self, raw_reward):
self._env_total_reward += raw_reward
self._env_episode_len += 1
self._env_discounted_return = raw_reward + self._gamma * self._env_discounted_return
def _normalize_rollout(self, rollout):
if self._obs_normalizer is not None:
observations = rollout['observations']
normalized_observations = self._obs_normalizer.normalize_vec(
observations)
rollout['observations'] = normalized_observations
if self._train_obs_normalizer:
self._obs_normalizer.update_vec(observations)
if self._reward_normalizer is not None:
rewards = rollout['rewards']
if self._normalize_reward:
normalized_rewards = self._reward_normalizer.normalize_vec(
rewards)
rollout['rewards'] = normalized_rewards
if self._train_reward_normalizer:
self._reward_normalizer.update_vec(rewards)
elif self._scale_reward:
normalized_rewards = self._reward_normalizer.scale_vec(rewards)
rollout['rewards'] = normalized_rewards
if self._train_reward_normalizer:
# TODO: this update is incorrect,
# need to store last returns at each step during rollout gathering
self._reward_normalizer.update_vec(
self._env_discounted_return)
return rollout
def _act_and_step(self, observation):
# calculate action, step environment, collect results into dict
act_result, act_time = self._act(None,
observation,
deterministic=False)
action = act_result['action']
env_step_result, env_time = self._env_step(self._train_env, action)
observation, reward, done, info = env_step_result
# convert info from tuple of dicts to dict of np.arrays
info = {
key: np.stack([info_env.get(key, None) for info_env in info])
for key in info[0].keys()
}
self._done_callback(done)
self._update_running_statistics(reward)
# reward, observation = self._call_after_env_step(raw_reward, observation)
result = {
'observation': observation,
'reward': reward,
'done': done,
'info': info,
**act_result
}
return result, act_time, env_time
@staticmethod
def _list_of_dicts_to_dict_of_np_array(list_of_dicts, super_key):
# useful to convert observations and infos
result = {
key: np.stack([x[super_key][key] for x in list_of_dicts])
for key in list_of_dicts[0][super_key].keys()
}
return result
def _rollout_from_list_to_dict(self, rollout, first_observation):
plural = {
'observation': 'observations',
'action': 'actions',
'reward': 'rewards',
'done': 'is_done',
}
# observation may be of type dict so it requires 'special' concatenation
if type(rollout[0]['observation']) is dict:
cat_observations = self._list_of_dicts_to_dict_of_np_array(
[{
'observation': first_observation
}, *rollout], 'observation')
else:
cat_observations = np.stack([
x['observation'] for x in [{
'observation': first_observation
}, *rollout]
])
cat_infos = self._list_of_dicts_to_dict_of_np_array(rollout, 'info')
keys = rollout[0].keys()
keys = [k for k in keys if k not in ['observation', 'info']]
rollout = {
plural.get(k, k): np.stack([x[k] for x in rollout])
for k in keys
}
rollout['observations'] = cat_observations
rollout['infos'] = cat_infos
return rollout
def _gather_rollout(self, observation, rollout_len):
# this function is called only when agent is training
start_time = time.time()
first_observation = observation
rollout = []
mean_act_time = 0
mean_env_time = 0
for _ in range(rollout_len):
act_step_result, act_time, env_time = self._act_and_step(
observation)
observation = act_step_result['observation']
rollout.append(act_step_result)
mean_act_time += act_time
mean_env_time += env_time
mean_act_time /= rollout_len
mean_env_time /= rollout_len
# now rollout is a list of dicts, convert it to dict of 'numpy.array'
rollout = self._rollout_from_list_to_dict(rollout, first_observation)
elapsed_time = time.time() - start_time
rewards = rollout['rewards']
rollout_log = {
'reward_mean': rewards.mean(),
'reward_std': rewards.std()
}
time_log = {
'mean_act_time': mean_act_time,
'mean_env_time': mean_env_time,
'gather_rollout_time': elapsed_time
}
return observation, rollout, rollout_log, time_log
def _small_done_callback(self, i):
self._writer.add_scalars('agents/train_reward/',
{f'agent_{i}': self._env_total_reward[i]},
self._env_episode_number[i])
self._writer.add_scalars('agents/train_ep_len/',
{f'agent_{i}': self._env_episode_len[i]},
self._env_episode_number[i])
self._env_total_reward[i] = 0.0
self._env_episode_len[i] = 0
self._env_discounted_return[i] = 0.0
self._env_episode_number[i] += 1
def _done_callback(self, done):
if np.any(done):
for i, d in enumerate(done):
if d:
self._small_done_callback(i)
def _train_step(self, observation, rollout_len, step, train_agent=True):
# gather rollout -> train on it -> write training logs
observation, rollout, rollout_log, time_log = self._gather_rollout(
observation, rollout_len)
rollout = self._normalize_rollout(rollout)
if train_agent:
train_logs, time_logs = self._agent_train.train_on_rollout(rollout)
else:
train_logs, time_logs = dict(), dict()
train_logs.update(rollout_log)
time_logs.update(time_log)
self._write_logs('train/', train_logs, step)
self._write_logs('time/', time_logs, step)
return observation
def _update_online_agent(self):
self._agent_online.load_state_dict(self._agent_train.state_dict())
def train(self, n_epoch, n_steps_per_epoch, rollout_len,
n_tests_per_epoch):
"""
Run training for 'n_epoch', each epoch takes 'n_steps' training steps
on rollouts of len 'rollout_len'.
At the end of each epoch run 'n_tests' tests and saves checkpoint
:param n_epoch:
:param n_steps_per_epoch:
:param rollout_len:
:param n_tests_per_epoch:
:return:
"""
observation = self._train_env.reset()
self._save_n_test(0, n_tests_per_epoch, self._agent_online)
self._agent_train.train() # always in training mode
if self._warm_up_steps > 0:
# just update normalizers statistics without training agent
p_bar = trange(self._warm_up_steps, ncols=90, desc='warm_up')
for step in p_bar:
observation = self._train_step(observation,
rollout_len,
step,
train_agent=False)
for epoch in range(n_epoch):
self._agent_online.train()
p_bar = trange(n_steps_per_epoch, ncols=90, desc=f'epoch_{epoch}')
for train_step in p_bar:
step = train_step + epoch * n_steps_per_epoch + self._warm_up_steps
observation = self._train_step(observation, rollout_len, step)
if (step + 1) % self._update_period == 0:
self._update_online_agent()
self._update_online_agent()
self._save_n_test(epoch + 1, n_tests_per_epoch, self._agent_online)
self._writer.close()
class OnPolicyTrainer(BaseTrainer):
def __init__(
self,
agent_online, agent_train,
return_pi,
train_env,
update_period,
normalize_obs, train_obs_normalizer,
scale_reward, normalize_reward, train_reward_normalizer,
obs_clip, reward_clip,
warm_up_steps=0,
**kwargs
):
"""On-policy trainer
:param agent_online: agent which collects data
:param agent_train: agent which performs train-ops
:param return_pi: if True then 'act()' method will return
full policy parametrization instead of log-prob of sampled action
:param train_env: environment for collecting training data
:param test_env: environment for testing agent once per epoch
:param update_period: number of train-ops after which
online agent loads weights of training agent
:param normalize_obs: if True then observations will be normalized
by running mean and std of collected observations
:param train_obs_normalizer: if True then running mean and std of obs_normalizer
will be updated each environment step
:param scale_reward: if True then reward will be normalized
by running mean and std of collected episodes return
:param normalize_reward: if True then reward will be normalized
by running mean and std of collected rewards
:param train_reward_normalizer: if True then running mean and std of reward_normalizer
will be updated each environment step
:param obs_clip: abs(observation) will be clipped to this value after normalization
:param reward_clip: abs(reward) will be clipped to this value after normalization
:param warm_up_steps: number of steps not to update online agent,
useful to continue training from checkpoint
:param kwargs: test_env and log_dir
"""
super().__init__(**kwargs)
self._agent_online = agent_online # gather rollouts
self._agent_train = agent_train # do train-ops
self._update_online_agent()
# weights of online agent updated once in 'update_period' & at the end of training epoch
self._update_period = update_period
self._warm_up_steps = warm_up_steps
# if return_pi then agent append 'policy' tensor
# to rollout, else it append 'log_pi_a'
self._return_pi = return_pi
# both environments should:
# vectorized
# reset environment automatically
self._train_env = train_env
# normalizers:
self._obs_normalizer = RunningMeanStd() if normalize_obs else None
self._train_obs_normalizer = train_obs_normalizer
self._obs_clip = obs_clip
assert not (normalize_reward and scale_reward), \
'reward may be normalized or scaled, but not both at the same time!'
self._reward_scaler = RunningMeanStd() if scale_reward else None
self._reward_normalizer = RunningMeanStd() if normalize_reward else None
self._train_reward_normalizer = train_reward_normalizer
self._reward_clip = reward_clip
# store episode reward, length, return and number for each train environment
self._gamma = self._agent_train.gamma
self._env_reward = np.zeros(train_env.num_envs, dtype=np.float32)
self._env_episode_len = np.zeros(train_env.num_envs, dtype=np.int32)
self._env_return = np.zeros(train_env.num_envs, dtype=np.float32)
self._env_episode = np.zeros(train_env.num_envs, dtype=np.int32)
def save(self, filename):
state_dict = {'agent': self._agent_train.state_dict()}
if self._obs_normalizer is not None:
state_dict['obs_normalizer'] = self._obs_normalizer.state_dict()
if self._reward_normalizer is not None:
state_dict['reward_normalizer'] = self._reward_normalizer.state_dict()
torch.save(state_dict, filename)
def load(self, filename):
checkpoint = torch.load(filename)
self._agent_online.load_state_dict(checkpoint['agent'])
self._agent_train.load_state_dict(checkpoint['agent'])
if 'obs_normalizer' in checkpoint and self._obs_normalizer is not None:
self._obs_normalizer.load_state_dict(checkpoint['obs_normalizer'])
if 'reward_normalizer' in checkpoint and self._reward_normalizer is not None:
self._reward_normalizer.load_state_dict(checkpoint['reward_normalizer'])
@staticmethod
def stack_infos(infos):
keys = infos[0].keys()
stacked_info = dict()
for key in keys:
values = []
for info in infos:
values.append(info[key])
stacked_info[key] = np.stack(values)
return stacked_info
# def _act(self, fake_agent, observation, deterministic, training=False, **kwargs):
# # 'fake_agent' arg is unused to make this method work in BaseTrainer.test_agent_service
# observation = self._normalize_observation(observation, training)
# (action, log_prob), act_time = super()._act(
# self._agent_online, observation, deterministic,
# return_pi=self._return_pi
# )
# return (action, log_prob), act_time
def _act(self, fake_agent, observation, deterministic, need_norm=True, **kwargs):
# this method used ONLY inside base class '._test_agent_service()' method
# 'fake_agent' arg is unused to make this method work in BaseTrainer.test_agent_service
if need_norm:
observation = self._normalize_observation(observation, False)
(action, log_prob), act_time = super()._act(
self._agent_online, observation, deterministic,
return_pi=self._return_pi
)
return (action, log_prob), act_time
def _normalize_observation(self, observation, training):
if self._obs_normalizer is not None:
if training:
self._obs_normalizer.update(observation)
mean, var = self._obs_normalizer.mean, self._obs_normalizer.var
observation = (observation - mean) / np.sqrt(var + 1e-8)
observation = np.clip(observation, -self._obs_clip, self._obs_clip)
return observation
def _normalize_reward(self, reward, training):
# 'baselines' version:
if self._reward_scaler is not None:
if training:
self._reward_scaler.update(self._env_return)
var = self._reward_scaler.var
reward = reward / np.sqrt(var + 1e-8)
reward = np.clip(reward, -self._reward_clip, self._reward_clip)
# 'my' version:
if self._reward_normalizer is not None:
if training:
self._reward_normalizer.update(reward)
mean, var = self._reward_normalizer.mean, self._reward_normalizer.var
reward = (reward - mean) / np.sqrt(var + 1e-8)
reward = np.clip(reward, -self._reward_clip, self._reward_clip)
return reward
@time_it
def _gather_rollout(self, observation, rollout_len):
# this function only called when agent is trained
# initial observation (i.e. at the beginning of training) does not care about normalization
observations, actions, rewards, is_done = [observation], [], [], []
log_probs = []
raw_rewards = []
mean_act_time = 0
mean_env_time = 0
for _ in range(rollout_len):
# on-policy trainer does not requires actions to be differentiable
# however, agent may be used by different algorithms which may require that
(action, log_prob), act_time = self._act(None, observation, deterministic=False, need_norm=False)
mean_act_time += act_time
env_step_result, env_time = self._env_step(self._train_env, action)
observation, reward, done, _ = env_step_result
mean_env_time += env_time
self._env_reward += reward
self._env_episode_len += 1
self._env_return = reward + self._gamma * self._env_return
raw_rewards.append(np.copy(reward))
observation = self._normalize_observation(observation, training=self._train_obs_normalizer)
reward = self._normalize_reward(reward, training=self._train_reward_normalizer)
observations.append(observation)
actions.append(action)
rewards.append(reward)
is_done.append(done)
log_probs.append(log_prob)
self._done_callback(done)
mean_act_time /= rollout_len
mean_env_time /= rollout_len
rollout = observations, actions, rewards, is_done, log_probs
gather_result = rollout, raw_rewards, observation
mean_time = mean_act_time, mean_env_time
return gather_result, mean_time
def _done_callback(self, done):
if np.any(done):
for i, d in enumerate(done):
if d:
self._writer.add_scalars(
'agents/train_reward/',
{f'agent_{i}': self._env_reward[i]},
self._env_episode[i]
)
self._writer.add_scalars(
'agents/train_ep_len/',
{f'agent_{i}': self._env_episode_len[i]},
self._env_episode[i]
)
self._env_reward[i] = 0.0
self._env_episode_len[i] = 0
self._env_return[i] = 0.0
self._env_episode[i] += 1
def _train_step(self, observation, rollout_len, step):
# gather rollout -> train on it -> write training logs
(gather_result, mean_time), gather_time = self._gather_rollout(observation, rollout_len)
rollout, raw_rewards, observation = gather_result
mean_act_time, mean_env_time = mean_time
train_logs, time_logs = self._agent_train.train_on_rollout(rollout)
train_logs['reward_mean'] = np.mean(raw_rewards)
train_logs['reward_std'] = np.std(raw_rewards)
time_logs['mean_act_time'] = mean_act_time
time_logs['mean_env_time'] = mean_env_time
time_logs['gather_rollout_time'] = gather_time
self._write_logs('train/', train_logs, step)
self._write_logs('time/', time_logs, step)
return observation
def _update_online_agent(self):
self._agent_online.load_state_dict(self._agent_train.state_dict())
def _save_n_test(self, epoch, n_tests):
checkpoint_name = self._log_dir + 'checkpoints/' + f'epoch_{epoch}.pth'
self.save(checkpoint_name)
self._test_agent(epoch, n_tests, self._agent_online)
def train(self, n_epoch, n_steps_per_epoch, rollout_len, n_tests_per_epoch):
"""
Run training for 'n_epoch', each epoch takes 'n_steps' training steps
on rollouts of len 'rollout_len'.
At the end of each epoch run 'n_tests' tests and saves checkpoint
:param n_epoch:
:param n_steps_per_epoch:
:param rollout_len:
:param n_tests_per_epoch:
:return:
"""
observation = self._train_env.reset()
self._save_n_test(0, n_tests_per_epoch)
self._agent_train.train() # always in training mode
for epoch in range(n_epoch):
self._agent_online.train()
p_bar = trange(n_steps_per_epoch, ncols=90, desc=f'epoch_{epoch}')
for train_step in p_bar:
step = train_step + epoch * n_steps_per_epoch
observation = self._train_step(
observation, rollout_len, step
)
if step > self._warm_up_steps and (step + 1) % self._update_period == 0:
self._update_online_agent()
self._update_online_agent()
self._save_n_test(epoch + 1, n_tests_per_epoch)
self._writer.close()
class OnPolicyTrainer(BaseTrainer):
def __init__(
self,
agent_online,
agent_train,
train_env,
# kwargs comes from config
update_period=1,
normalize_obs=False,
train_obs_normalizer=False,
scale_reward=False,
normalize_reward=False,
train_reward_normalizer=False,
obs_clip=float('inf'),
reward_clip=float('inf'),
warm_up_steps=0,
**kwargs):
"""On-policy trainer
:param agent_online: agent which collects data
:param agent_train: agent which performs train-ops
:param train_env: environment for collecting training data
:param test_env: environment for testing agent once per epoch
:param update_period: number of train-ops after which
online agent loads weights of training agent
:param normalize_obs: if True then observations will be normalized
by running mean and std of collected observations
:param train_obs_normalizer: if True then running mean and std of obs_normalizer
will be updated each environment step
:param scale_reward: if True then reward will be normalized
by running mean and std of collected episodes return
:param normalize_reward: if True then reward will be normalized
by running mean and std of collected rewards
:param train_reward_normalizer: if True then running mean and std of reward_normalizer
will be updated each environment step
:param obs_clip: abs(observation) will be clipped to this value after normalization
:param reward_clip: abs(reward) will be clipped to this value after normalization
:param warm_up_steps: number of steps not to update online agent,
useful to continue training from checkpoint
:param kwargs: test_env and log_dir
"""
super().__init__(**kwargs)
self._agent_online = agent_online # gather rollouts
self._agent_train = agent_train # do train-ops
self._update_online_agent()
# weights of online agent updated once in 'update_period' & at the end of training epoch
self._update_period = update_period
self._warm_up_steps = warm_up_steps
# both environments should:
# vectorized
# reset environment automatically
self._train_env = train_env
# normalizers:
self._obs_normalizer = RunningMeanStd() if normalize_obs else None
self._train_obs_normalizer = train_obs_normalizer
self._obs_clip = obs_clip
assert not (normalize_reward and scale_reward), \
'reward may be normalized or scaled, but not both at the same time!'
self._reward_scaler = RunningMeanStd() if scale_reward else None
self._reward_normalizer = RunningMeanStd(
) if normalize_reward else None
self._train_reward_normalizer = train_reward_normalizer
self._reward_clip = reward_clip
self._gamma = self._agent_train.gamma
# store episode reward, length, return and number for each train environment
self._env_total_reward = np.zeros(train_env.num_envs, dtype=np.float32)
self._env_episode_len = np.zeros(train_env.num_envs, dtype=np.int32)
self._env_discounted_return = np.zeros(train_env.num_envs,
dtype=np.float32)
self._env_episode_number = np.zeros(train_env.num_envs, dtype=np.int32)
def save(self, filename):
state_dict = {'agent': self._agent_train.state_dict()}
if self._obs_normalizer is not None:
state_dict['obs_normalizer'] = self._obs_normalizer.state_dict()
if self._reward_normalizer is not None:
state_dict[
'reward_normalizer'] = self._reward_normalizer.state_dict()
torch.save(state_dict, filename)
def load(self, filename):
checkpoint = torch.load(filename)
self._agent_online.load_state_dict(checkpoint['agent'])
self._agent_train.load_state_dict(checkpoint['agent'])
if 'obs_normalizer' in checkpoint and self._obs_normalizer is not None:
self._obs_normalizer.load_state_dict(checkpoint['obs_normalizer'])
if 'reward_normalizer' in checkpoint and self._reward_normalizer is not None:
self._reward_normalizer.load_state_dict(
checkpoint['reward_normalizer'])
def _act(self,
fake_agent,
observation,
deterministic,
need_norm=True,
**kwargs):
# this method used ONLY inside base class '._test_agent_service()' method
# 'fake_agent' arg is unused to make this method work in BaseTrainer.test_agent_service
if need_norm:
observation = self._normalize_observation(observation, False)
return super()._act(self._agent_online, observation, deterministic)
def _normalize_observation(self, observation, training):
if self._obs_normalizer is not None:
if training:
self._obs_normalizer.update(observation)
mean, var = self._obs_normalizer.mean, self._obs_normalizer.var
observation = (observation - mean) / np.maximum(np.sqrt(var), 1e-6)
observation = np.clip(observation, -self._obs_clip, self._obs_clip)
return observation
def _normalize_reward(self, reward, training):
# 'baselines' version:
if self._reward_scaler is not None:
if training:
self._reward_scaler.update(self._env_discounted_return)
var = self._reward_scaler.var
reward = reward / np.maximum(np.sqrt(var), 1e-6)
reward = np.clip(reward, -self._reward_clip, self._reward_clip)
# 'my' version:
if self._reward_normalizer is not None:
if training:
self._reward_normalizer.update(reward)
mean, var = self._reward_normalizer.mean, self._reward_normalizer.var
reward = (reward - mean) / np.maximum(np.sqrt(var), 1e-6)
reward = np.clip(reward, -self._reward_clip, self._reward_clip)
return reward
def _call_after_env_step(self, reward, observation):
# update running statistics and normalize reward & observation
self._env_total_reward += reward
self._env_episode_len += 1
self._env_discounted_return = reward + self._gamma * self._env_discounted_return
observation = self._normalize_observation(
observation, training=self._train_obs_normalizer)
reward = self._normalize_reward(reward,
training=self._train_reward_normalizer)
return reward, observation
@time_it
def _gather_rollout(self, observation, rollout_len):
# this function is called only when agent is training
# initial observation (i.e. at the beginning of training) does not care about normalization
raw_rewards = []
observations, rewards, is_done = [observation], [], []
act_results = [] # actions, values, log-probs, policy goes here
mean_act_time = 0
mean_env_time = 0
for _ in range(rollout_len):
act_result, act_time = self._act(None,
observation,
deterministic=False,
need_norm=False)
action = act_result['action']
mean_act_time += act_time
env_step_result, env_time = self._env_step(self._train_env, action)
observation, reward, done, _ = env_step_result
mean_env_time += env_time
raw_rewards.append(np.copy(reward))
reward, observation = self._call_after_env_step(
reward, observation)
observations.append(observation)
rewards.append(reward)
is_done.append(done)
act_results.append(act_result)
self._done_callback(done)
mean_act_time /= rollout_len
mean_env_time /= rollout_len
# act_results here is a list of dicts, convert it to dict of 'numpy.array'
act_results = {
k: np.stack([x[k] for x in act_results])
for k in act_results[0].keys()
}
act_results['actions'] = act_results.pop('action')
rollout = {
'observations': observations,
'rewards': rewards,
'is_done': is_done,
**act_results
}
gather_result = rollout, raw_rewards, observation
mean_time = mean_act_time, mean_env_time
return gather_result, mean_time
def _small_done_callback(self, i):
self._writer.add_scalars('agents/train_reward/',
{f'agent_{i}': self._env_total_reward[i]},
self._env_episode_number[i])
self._writer.add_scalars('agents/train_ep_len/',
{f'agent_{i}': self._env_episode_len[i]},
self._env_episode_number[i])
self._env_total_reward[i] = 0.0
self._env_episode_len[i] = 0
self._env_discounted_return[i] = 0.0
self._env_episode_number[i] += 1
def _done_callback(self, done):
if np.any(done):
for i, d in enumerate(done):
if d:
self._small_done_callback(i)
def _train_step(self, observation, rollout_len, step):
# gather rollout -> train on it -> write training logs
(gather_result, mean_time), gather_time = self._gather_rollout(
observation, rollout_len)
rollout, raw_rewards, observation = gather_result
mean_act_time, mean_env_time = mean_time
train_logs, time_logs = self._agent_train.train_on_rollout(rollout)
train_logs['reward_mean'] = np.mean(raw_rewards)
train_logs['reward_std'] = np.std(raw_rewards)
time_logs['mean_act_time'] = mean_act_time
time_logs['mean_env_time'] = mean_env_time
time_logs['gather_rollout_time'] = gather_time
self._write_logs('train/', train_logs, step)
self._write_logs('time/', time_logs, step)
return observation
def _update_online_agent(self):
self._agent_online.load_state_dict(self._agent_train.state_dict())
def train(self, n_epoch, n_steps_per_epoch, rollout_len,
n_tests_per_epoch):
"""
Run training for 'n_epoch', each epoch takes 'n_steps' training steps
on rollouts of len 'rollout_len'.
At the end of each epoch run 'n_tests' tests and saves checkpoint
:param n_epoch:
:param n_steps_per_epoch:
:param rollout_len:
:param n_tests_per_epoch:
:return:
"""
observation = self._train_env.reset()
self._save_n_test(0, n_tests_per_epoch, self._agent_online)
self._agent_train.train() # always in training mode
for epoch in range(n_epoch):
self._agent_online.train()
p_bar = trange(n_steps_per_epoch, ncols=90, desc=f'epoch_{epoch}')
for train_step in p_bar:
step = train_step + epoch * n_steps_per_epoch
observation = self._train_step(observation, rollout_len, step)
if step > self._warm_up_steps and (
step + 1) % self._update_period == 0:
self._update_online_agent()
self._update_online_agent()
self._save_n_test(epoch + 1, n_tests_per_epoch, self._agent_online)
self._writer.close()