class TorchSACOptimizer(TorchOptimizer):
class PolicyValueNetwork(nn.Module):
def __init__(
self,
stream_names: List[str],
sensor_specs: List[SensorSpec],
network_settings: NetworkSettings,
action_spec: ActionSpec,
):
super().__init__()
num_value_outs = max(sum(action_spec.discrete_branches), 1)
num_action_ins = int(action_spec.continuous_size)
self.q1_network = ValueNetwork(
stream_names,
sensor_specs,
network_settings,
num_action_ins,
num_value_outs,
)
self.q2_network = ValueNetwork(
stream_names,
sensor_specs,
network_settings,
num_action_ins,
num_value_outs,
)
def forward(
self,
inputs: List[torch.Tensor],
actions: Optional[torch.Tensor] = None,
memories: Optional[torch.Tensor] = None,
sequence_length: int = 1,
q1_grad: bool = True,
q2_grad: bool = True,
) -> Tuple[Dict[str, torch.Tensor], Dict[str, torch.Tensor]]:
"""
Performs a forward pass on the value network, which consists of a Q1 and Q2
network. Optionally does not evaluate gradients for either the Q1, Q2, or both.
:param inputs: List of observation tensors.
:param actions: For a continuous Q function (has actions), tensor of actions.
Otherwise, None.
:param memories: Initial memories if using memory. Otherwise, None.
:param sequence_length: Sequence length if using memory.
:param q1_grad: Whether or not to compute gradients for the Q1 network.
:param q2_grad: Whether or not to compute gradients for the Q2 network.
:return: Tuple of two dictionaries, which both map {reward_signal: Q} for Q1 and Q2,
respectively.
"""
# ExitStack allows us to enter the torch.no_grad() context conditionally
with ExitStack() as stack:
if not q1_grad:
stack.enter_context(torch.no_grad()) # pylint: disable=E1101
q1_out, _ = self.q1_network(
inputs,
actions=actions,
memories=memories,
sequence_length=sequence_length,
)
with ExitStack() as stack:
if not q2_grad:
stack.enter_context(torch.no_grad()) # pylint: disable=E1101
q2_out, _ = self.q2_network(
inputs,
actions=actions,
memories=memories,
sequence_length=sequence_length,
)
return q1_out, q2_out
class TargetEntropy(NamedTuple):
discrete: List[float] = [] # One per branch
continuous: float = 0.0
class LogEntCoef(nn.Module):
def __init__(self, discrete, continuous):
super().__init__()
self.discrete = discrete
self.continuous = continuous
def __init__(self, policy: TorchPolicy, trainer_params: TrainerSettings):
super().__init__(policy, trainer_params)
hyperparameters: SACSettings = cast(SACSettings,
trainer_params.hyperparameters)
self.tau = hyperparameters.tau
self.init_entcoef = hyperparameters.init_entcoef
self.policy = policy
policy_network_settings = policy.network_settings
self.tau = hyperparameters.tau
self.burn_in_ratio = 0.0
# Non-exposed SAC parameters
self.discrete_target_entropy_scale = 0.2 # Roughly equal to e-greedy 0.05
self.continuous_target_entropy_scale = 1.0
self.stream_names = list(self.reward_signals.keys())
# Use to reduce "survivor bonus" when using Curiosity or GAIL.
self.gammas = [
_val.gamma for _val in trainer_params.reward_signals.values()
]
self.use_dones_in_backup = {
name: int(not self.reward_signals[name].ignore_done)
for name in self.stream_names
}
self._action_spec = self.policy.behavior_spec.action_spec
self.value_network = TorchSACOptimizer.PolicyValueNetwork(
self.stream_names,
self.policy.behavior_spec.sensor_specs,
policy_network_settings,
self._action_spec,
)
self.target_network = ValueNetwork(
self.stream_names,
self.policy.behavior_spec.sensor_specs,
policy_network_settings,
)
ModelUtils.soft_update(self.policy.actor_critic.critic,
self.target_network, 1.0)
# We create one entropy coefficient per action, whether discrete or continuous.
_disc_log_ent_coef = torch.nn.Parameter(
torch.log(
torch.as_tensor([self.init_entcoef] *
len(self._action_spec.discrete_branches))),
requires_grad=True,
)
_cont_log_ent_coef = torch.nn.Parameter(torch.log(
torch.as_tensor([self.init_entcoef])),
requires_grad=True)
self._log_ent_coef = TorchSACOptimizer.LogEntCoef(
discrete=_disc_log_ent_coef, continuous=_cont_log_ent_coef)
_cont_target = (
-1 * self.continuous_target_entropy_scale *
np.prod(self._action_spec.continuous_size).astype(np.float32))
_disc_target = [
self.discrete_target_entropy_scale * np.log(i).astype(np.float32)
for i in self._action_spec.discrete_branches
]
self.target_entropy = TorchSACOptimizer.TargetEntropy(
continuous=_cont_target, discrete=_disc_target)
policy_params = list(
self.policy.actor_critic.network_body.parameters()) + list(
self.policy.actor_critic.action_model.parameters())
value_params = list(self.value_network.parameters()) + list(
self.policy.actor_critic.critic.parameters())
logger.debug("value_vars")
for param in value_params:
logger.debug(param.shape)
logger.debug("policy_vars")
for param in policy_params:
logger.debug(param.shape)
self.decay_learning_rate = ModelUtils.DecayedValue(
hyperparameters.learning_rate_schedule,
hyperparameters.learning_rate,
1e-10,
self.trainer_settings.max_steps,
)
self.policy_optimizer = torch.optim.Adam(
policy_params, lr=hyperparameters.learning_rate)
self.value_optimizer = torch.optim.Adam(
value_params, lr=hyperparameters.learning_rate)
self.entropy_optimizer = torch.optim.Adam(
self._log_ent_coef.parameters(), lr=hyperparameters.learning_rate)
self._move_to_device(default_device())
def _move_to_device(self, device: torch.device) -> None:
self._log_ent_coef.to(device)
self.target_network.to(device)
self.value_network.to(device)
def sac_q_loss(
self,
q1_out: Dict[str, torch.Tensor],
q2_out: Dict[str, torch.Tensor],
target_values: Dict[str, torch.Tensor],
dones: torch.Tensor,
rewards: Dict[str, torch.Tensor],
loss_masks: torch.Tensor,
) -> Tuple[torch.Tensor, torch.Tensor]:
q1_losses = []
q2_losses = []
# Multiple q losses per stream
for i, name in enumerate(q1_out.keys()):
q1_stream = q1_out[name].squeeze()
q2_stream = q2_out[name].squeeze()
with torch.no_grad():
q_backup = rewards[name] + (
(1.0 - self.use_dones_in_backup[name] * dones) *
self.gammas[i] * target_values[name])
_q1_loss = 0.5 * ModelUtils.masked_mean(
torch.nn.functional.mse_loss(q_backup, q1_stream), loss_masks)
_q2_loss = 0.5 * ModelUtils.masked_mean(
torch.nn.functional.mse_loss(q_backup, q2_stream), loss_masks)
q1_losses.append(_q1_loss)
q2_losses.append(_q2_loss)
q1_loss = torch.mean(torch.stack(q1_losses))
q2_loss = torch.mean(torch.stack(q2_losses))
return q1_loss, q2_loss
def sac_value_loss(
self,
log_probs: ActionLogProbs,
values: Dict[str, torch.Tensor],
q1p_out: Dict[str, torch.Tensor],
q2p_out: Dict[str, torch.Tensor],
loss_masks: torch.Tensor,
) -> torch.Tensor:
min_policy_qs = {}
with torch.no_grad():
_cont_ent_coef = self._log_ent_coef.continuous.exp()
_disc_ent_coef = self._log_ent_coef.discrete.exp()
for name in values.keys():
if self._action_spec.discrete_size <= 0:
min_policy_qs[name] = torch.min(q1p_out[name],
q2p_out[name])
else:
disc_action_probs = log_probs.all_discrete_tensor.exp()
_branched_q1p = ModelUtils.break_into_branches(
q1p_out[name] * disc_action_probs,
self._action_spec.discrete_branches,
)
_branched_q2p = ModelUtils.break_into_branches(
q2p_out[name] * disc_action_probs,
self._action_spec.discrete_branches,
)
_q1p_mean = torch.mean(
torch.stack([
torch.sum(_br, dim=1, keepdim=True)
for _br in _branched_q1p
]),
dim=0,
)
_q2p_mean = torch.mean(
torch.stack([
torch.sum(_br, dim=1, keepdim=True)
for _br in _branched_q2p
]),
dim=0,
)
min_policy_qs[name] = torch.min(_q1p_mean, _q2p_mean)
value_losses = []
if self._action_spec.discrete_size <= 0:
for name in values.keys():
with torch.no_grad():
v_backup = min_policy_qs[name] - torch.sum(
_cont_ent_coef * log_probs.continuous_tensor, dim=1)
value_loss = 0.5 * ModelUtils.masked_mean(
torch.nn.functional.mse_loss(values[name], v_backup),
loss_masks)
value_losses.append(value_loss)
else:
disc_log_probs = log_probs.all_discrete_tensor
branched_per_action_ent = ModelUtils.break_into_branches(
disc_log_probs * disc_log_probs.exp(),
self._action_spec.discrete_branches,
)
# We have to do entropy bonus per action branch
branched_ent_bonus = torch.stack([
torch.sum(_disc_ent_coef[i] * _lp, dim=1, keepdim=True)
for i, _lp in enumerate(branched_per_action_ent)
])
for name in values.keys():
with torch.no_grad():
v_backup = min_policy_qs[name] - torch.mean(
branched_ent_bonus, axis=0)
# Add continuous entropy bonus to minimum Q
if self._action_spec.continuous_size > 0:
v_backup += torch.sum(
_cont_ent_coef * log_probs.continuous_tensor,
dim=1,
keepdim=True,
)
value_loss = 0.5 * ModelUtils.masked_mean(
torch.nn.functional.mse_loss(values[name],
v_backup.squeeze()),
loss_masks,
)
value_losses.append(value_loss)
value_loss = torch.mean(torch.stack(value_losses))
if torch.isinf(value_loss).any() or torch.isnan(value_loss).any():
raise UnityTrainerException("Inf found")
return value_loss
def sac_policy_loss(
self,
log_probs: ActionLogProbs,
q1p_outs: Dict[str, torch.Tensor],
loss_masks: torch.Tensor,
) -> torch.Tensor:
_cont_ent_coef, _disc_ent_coef = (
self._log_ent_coef.continuous,
self._log_ent_coef.discrete,
)
_cont_ent_coef = _cont_ent_coef.exp()
_disc_ent_coef = _disc_ent_coef.exp()
mean_q1 = torch.mean(torch.stack(list(q1p_outs.values())), axis=0)
batch_policy_loss = 0
if self._action_spec.discrete_size > 0:
disc_log_probs = log_probs.all_discrete_tensor
disc_action_probs = disc_log_probs.exp()
branched_per_action_ent = ModelUtils.break_into_branches(
disc_log_probs * disc_action_probs,
self._action_spec.discrete_branches)
branched_q_term = ModelUtils.break_into_branches(
mean_q1 * disc_action_probs,
self._action_spec.discrete_branches)
branched_policy_loss = torch.stack(
[
torch.sum(
_disc_ent_coef[i] * _lp - _qt, dim=1, keepdim=False)
for i, (_lp, _qt) in enumerate(
zip(branched_per_action_ent, branched_q_term))
],
dim=1,
)
batch_policy_loss += torch.sum(branched_policy_loss, dim=1)
all_mean_q1 = torch.sum(disc_action_probs * mean_q1, dim=1)
else:
all_mean_q1 = mean_q1
if self._action_spec.continuous_size > 0:
cont_log_probs = log_probs.continuous_tensor
batch_policy_loss += torch.mean(_cont_ent_coef * cont_log_probs -
all_mean_q1.unsqueeze(1),
dim=1)
policy_loss = ModelUtils.masked_mean(batch_policy_loss, loss_masks)
return policy_loss
def sac_entropy_loss(self, log_probs: ActionLogProbs,
loss_masks: torch.Tensor) -> torch.Tensor:
_cont_ent_coef, _disc_ent_coef = (
self._log_ent_coef.continuous,
self._log_ent_coef.discrete,
)
entropy_loss = 0
if self._action_spec.discrete_size > 0:
with torch.no_grad():
# Break continuous into separate branch
disc_log_probs = log_probs.all_discrete_tensor
branched_per_action_ent = ModelUtils.break_into_branches(
disc_log_probs * disc_log_probs.exp(),
self._action_spec.discrete_branches,
)
target_current_diff_branched = torch.stack(
[
torch.sum(_lp, axis=1, keepdim=True) + _te
for _lp, _te in zip(branched_per_action_ent,
self.target_entropy.discrete)
],
axis=1,
)
target_current_diff = torch.squeeze(
target_current_diff_branched, axis=2)
entropy_loss += -1 * ModelUtils.masked_mean(
torch.mean(_disc_ent_coef * target_current_diff, axis=1),
loss_masks)
if self._action_spec.continuous_size > 0:
with torch.no_grad():
cont_log_probs = log_probs.continuous_tensor
target_current_diff = torch.sum(cont_log_probs +
self.target_entropy.continuous,
dim=1)
# We update all the _cont_ent_coef as one block
entropy_loss += -1 * ModelUtils.masked_mean(
_cont_ent_coef * target_current_diff, loss_masks)
return entropy_loss
def _condense_q_streams(
self, q_output: Dict[str, torch.Tensor],
discrete_actions: torch.Tensor) -> Dict[str, torch.Tensor]:
condensed_q_output = {}
onehot_actions = ModelUtils.actions_to_onehot(
discrete_actions, self._action_spec.discrete_branches)
for key, item in q_output.items():
branched_q = ModelUtils.break_into_branches(
item, self._action_spec.discrete_branches)
only_action_qs = torch.stack([
torch.sum(_act * _q, dim=1, keepdim=True)
for _act, _q in zip(onehot_actions, branched_q)
])
condensed_q_output[key] = torch.mean(only_action_qs, dim=0)
return condensed_q_output
@timed
def update(self, batch: AgentBuffer,
num_sequences: int) -> Dict[str, float]:
"""
Updates model using buffer.
:param num_sequences: Number of trajectories in batch.
:param batch: Experience mini-batch.
:param update_target: Whether or not to update target value network
:param reward_signal_batches: Minibatches to use for updating the reward signals,
indexed by name. If none, don't update the reward signals.
:return: Output from update process.
"""
rewards = {}
for name in self.reward_signals:
rewards[name] = ModelUtils.list_to_tensor(batch[f"{name}_rewards"])
n_obs = len(self.policy.behavior_spec.sensor_specs)
current_obs = ObsUtil.from_buffer(batch, n_obs)
# Convert to tensors
current_obs = [ModelUtils.list_to_tensor(obs) for obs in current_obs]
next_obs = ObsUtil.from_buffer_next(batch, n_obs)
# Convert to tensors
next_obs = [ModelUtils.list_to_tensor(obs) for obs in next_obs]
act_masks = ModelUtils.list_to_tensor(batch["action_mask"])
actions = AgentAction.from_dict(batch)
memories_list = [
ModelUtils.list_to_tensor(batch["memory"][i]) for i in range(
0, len(batch["memory"]), self.policy.sequence_length)
]
# LSTM shouldn't have sequence length <1, but stop it from going out of the index if true.
offset = 1 if self.policy.sequence_length > 1 else 0
next_memories_list = [
ModelUtils.list_to_tensor(
batch["memory"][i]
[self.policy.m_size //
2:]) # only pass value part of memory to target network
for i in range(offset, len(batch["memory"]),
self.policy.sequence_length)
]
if len(memories_list) > 0:
memories = torch.stack(memories_list).unsqueeze(0)
next_memories = torch.stack(next_memories_list).unsqueeze(0)
else:
memories = None
next_memories = None
# Q network memories are 0'ed out, since we don't have them during inference.
q_memories = (torch.zeros_like(next_memories)
if next_memories is not None else None)
# Copy normalizers from policy
self.value_network.q1_network.network_body.copy_normalization(
self.policy.actor_critic.network_body)
self.value_network.q2_network.network_body.copy_normalization(
self.policy.actor_critic.network_body)
self.target_network.network_body.copy_normalization(
self.policy.actor_critic.network_body)
(
sampled_actions,
log_probs,
_,
value_estimates,
_,
) = self.policy.actor_critic.get_action_stats_and_value(
current_obs,
masks=act_masks,
memories=memories,
sequence_length=self.policy.sequence_length,
)
cont_sampled_actions = sampled_actions.continuous_tensor
cont_actions = actions.continuous_tensor
q1p_out, q2p_out = self.value_network(
current_obs,
cont_sampled_actions,
memories=q_memories,
sequence_length=self.policy.sequence_length,
q2_grad=False,
)
q1_out, q2_out = self.value_network(
current_obs,
cont_actions,
memories=q_memories,
sequence_length=self.policy.sequence_length,
)
if self._action_spec.discrete_size > 0:
disc_actions = actions.discrete_tensor
q1_stream = self._condense_q_streams(q1_out, disc_actions)
q2_stream = self._condense_q_streams(q2_out, disc_actions)
else:
q1_stream, q2_stream = q1_out, q2_out
with torch.no_grad():
target_values, _ = self.target_network(
next_obs,
memories=next_memories,
sequence_length=self.policy.sequence_length,
)
masks = ModelUtils.list_to_tensor(batch["masks"], dtype=torch.bool)
dones = ModelUtils.list_to_tensor(batch["done"])
q1_loss, q2_loss = self.sac_q_loss(q1_stream, q2_stream, target_values,
dones, rewards, masks)
value_loss = self.sac_value_loss(log_probs, value_estimates, q1p_out,
q2p_out, masks)
policy_loss = self.sac_policy_loss(log_probs, q1p_out, masks)
entropy_loss = self.sac_entropy_loss(log_probs, masks)
total_value_loss = q1_loss + q2_loss + value_loss
decay_lr = self.decay_learning_rate.get_value(
self.policy.get_current_step())
ModelUtils.update_learning_rate(self.policy_optimizer, decay_lr)
self.policy_optimizer.zero_grad()
policy_loss.backward()
self.policy_optimizer.step()
ModelUtils.update_learning_rate(self.value_optimizer, decay_lr)
self.value_optimizer.zero_grad()
total_value_loss.backward()
self.value_optimizer.step()
ModelUtils.update_learning_rate(self.entropy_optimizer, decay_lr)
self.entropy_optimizer.zero_grad()
entropy_loss.backward()
self.entropy_optimizer.step()
# Update target network
ModelUtils.soft_update(self.policy.actor_critic.critic,
self.target_network, self.tau)
update_stats = {
"Losses/Policy Loss":
policy_loss.item(),
"Losses/Value Loss":
value_loss.item(),
"Losses/Q1 Loss":
q1_loss.item(),
"Losses/Q2 Loss":
q2_loss.item(),
"Policy/Discrete Entropy Coeff":
torch.mean(torch.exp(self._log_ent_coef.discrete)).item(),
"Policy/Continuous Entropy Coeff":
torch.mean(torch.exp(self._log_ent_coef.continuous)).item(),
"Policy/Learning Rate":
decay_lr,
}
return update_stats
def update_reward_signals(self,
reward_signal_minibatches: Mapping[str,
AgentBuffer],
num_sequences: int) -> Dict[str, float]:
update_stats: Dict[str, float] = {}
for name, update_buffer in reward_signal_minibatches.items():
update_stats.update(
self.reward_signals[name].update(update_buffer))
return update_stats
def get_modules(self):
modules = {
"Optimizer:value_network": self.value_network,
"Optimizer:target_network": self.target_network,
"Optimizer:policy_optimizer": self.policy_optimizer,
"Optimizer:value_optimizer": self.value_optimizer,
"Optimizer:entropy_optimizer": self.entropy_optimizer,
}
for reward_provider in self.reward_signals.values():
modules.update(reward_provider.get_modules())
return modules
class TorchPPOOptimizer(TorchOptimizer):
def __init__(self, policy: TorchPolicy, trainer_settings: TrainerSettings):
"""
Takes a Policy and a Dict of trainer parameters and creates an Optimizer around the policy.
The PPO optimizer has a value estimator and a loss function.
:param policy: A TorchPolicy object that will be updated by this PPO Optimizer.
:param trainer_params: Trainer parameters dictionary that specifies the
properties of the trainer.
"""
# Create the graph here to give more granular control of the TF graph to the Optimizer.
super().__init__(policy, trainer_settings)
reward_signal_configs = trainer_settings.reward_signals
reward_signal_names = [
key.value for key, _ in reward_signal_configs.items()
]
if policy.shared_critic:
self._critic = policy.actor
else:
self._critic = ValueNetwork(
reward_signal_names,
policy.behavior_spec.observation_specs,
network_settings=trainer_settings.network_settings,
)
self._critic.to(default_device())
params = list(self.policy.actor.parameters()) + list(
self._critic.parameters())
self.hyperparameters: PPOSettings = cast(
PPOSettings, trainer_settings.hyperparameters)
self.decay_learning_rate = ModelUtils.DecayedValue(
self.hyperparameters.learning_rate_schedule,
self.hyperparameters.learning_rate,
1e-10,
self.trainer_settings.max_steps,
)
self.decay_epsilon = ModelUtils.DecayedValue(
self.hyperparameters.learning_rate_schedule,
self.hyperparameters.epsilon,
0.1,
self.trainer_settings.max_steps,
)
self.decay_beta = ModelUtils.DecayedValue(
self.hyperparameters.learning_rate_schedule,
self.hyperparameters.beta,
1e-5,
self.trainer_settings.max_steps,
)
self.optimizer = torch.optim.Adam(
params, lr=self.trainer_settings.hyperparameters.learning_rate)
self.stats_name_to_update_name = {
"Losses/Value Loss": "value_loss",
"Losses/Policy Loss": "policy_loss",
}
self.stream_names = list(self.reward_signals.keys())
@property
def critic(self):
return self._critic
def ppo_value_loss(
self,
values: Dict[str, torch.Tensor],
old_values: Dict[str, torch.Tensor],
returns: Dict[str, torch.Tensor],
epsilon: float,
loss_masks: torch.Tensor,
) -> torch.Tensor:
"""
Evaluates value loss for PPO.
:param values: Value output of the current network.
:param old_values: Value stored with experiences in buffer.
:param returns: Computed returns.
:param epsilon: Clipping value for value estimate.
:param loss_mask: Mask for losses. Used with LSTM to ignore 0'ed out experiences.
"""
value_losses = []
for name, head in values.items():
old_val_tensor = old_values[name]
returns_tensor = returns[name]
clipped_value_estimate = old_val_tensor + torch.clamp(
head - old_val_tensor, -1 * epsilon, epsilon)
v_opt_a = (returns_tensor - head)**2
v_opt_b = (returns_tensor - clipped_value_estimate)**2
value_loss = ModelUtils.masked_mean(torch.max(v_opt_a, v_opt_b),
loss_masks)
value_losses.append(value_loss)
value_loss = torch.mean(torch.stack(value_losses))
return value_loss
def ppo_policy_loss(
self,
advantages: torch.Tensor,
log_probs: torch.Tensor,
old_log_probs: torch.Tensor,
loss_masks: torch.Tensor,
) -> torch.Tensor:
"""
Evaluate PPO policy loss.
:param advantages: Computed advantages.
:param log_probs: Current policy probabilities
:param old_log_probs: Past policy probabilities
:param loss_masks: Mask for losses. Used with LSTM to ignore 0'ed out experiences.
"""
advantage = advantages.unsqueeze(-1)
decay_epsilon = self.hyperparameters.epsilon
r_theta = torch.exp(log_probs - old_log_probs)
p_opt_a = r_theta * advantage
p_opt_b = (
torch.clamp(r_theta, 1.0 - decay_epsilon, 1.0 + decay_epsilon) *
advantage)
policy_loss = -1 * ModelUtils.masked_mean(torch.min(p_opt_a, p_opt_b),
loss_masks)
return policy_loss
@timed
def update(self, batch: AgentBuffer,
num_sequences: int) -> Dict[str, float]:
"""
Performs update on model.
:param batch: Batch of experiences.
:param num_sequences: Number of sequences to process.
:return: Results of update.
"""
# Get decayed parameters
decay_lr = self.decay_learning_rate.get_value(
self.policy.get_current_step())
decay_eps = self.decay_epsilon.get_value(
self.policy.get_current_step())
decay_bet = self.decay_beta.get_value(self.policy.get_current_step())
returns = {}
old_values = {}
for name in self.reward_signals:
old_values[name] = ModelUtils.list_to_tensor(
batch[RewardSignalUtil.value_estimates_key(name)])
returns[name] = ModelUtils.list_to_tensor(
batch[RewardSignalUtil.returns_key(name)])
n_obs = len(self.policy.behavior_spec.observation_specs)
current_obs = ObsUtil.from_buffer(batch, n_obs)
# Convert to tensors
current_obs = [ModelUtils.list_to_tensor(obs) for obs in current_obs]
act_masks = ModelUtils.list_to_tensor(batch[BufferKey.ACTION_MASK])
actions = AgentAction.from_buffer(batch)
memories = [
ModelUtils.list_to_tensor(batch[BufferKey.MEMORY][i]) for i in
range(0, len(batch[BufferKey.MEMORY]), self.policy.sequence_length)
]
if len(memories) > 0:
memories = torch.stack(memories).unsqueeze(0)
# Get value memories
value_memories = [
ModelUtils.list_to_tensor(batch[BufferKey.CRITIC_MEMORY][i])
for i in range(0, len(batch[BufferKey.CRITIC_MEMORY]),
self.policy.sequence_length)
]
if len(value_memories) > 0:
value_memories = torch.stack(value_memories).unsqueeze(0)
log_probs, entropy = self.policy.evaluate_actions(
current_obs,
masks=act_masks,
actions=actions,
memories=memories,
seq_len=self.policy.sequence_length,
)
values, _ = self.critic.critic_pass(
current_obs,
memories=value_memories,
sequence_length=self.policy.sequence_length,
)
old_log_probs = ActionLogProbs.from_buffer(batch).flatten()
log_probs = log_probs.flatten()
loss_masks = ModelUtils.list_to_tensor(batch[BufferKey.MASKS],
dtype=torch.bool)
value_loss = self.ppo_value_loss(values, old_values, returns,
decay_eps, loss_masks)
policy_loss = self.ppo_policy_loss(
ModelUtils.list_to_tensor(batch[BufferKey.ADVANTAGES]),
log_probs,
old_log_probs,
loss_masks,
)
loss = (policy_loss + 0.5 * value_loss -
decay_bet * ModelUtils.masked_mean(entropy, loss_masks))
# Set optimizer learning rate
ModelUtils.update_learning_rate(self.optimizer, decay_lr)
self.optimizer.zero_grad()
loss.backward()
self.optimizer.step()
update_stats = {
# NOTE: abs() is not technically correct, but matches the behavior in TensorFlow.
# TODO: After PyTorch is default, change to something more correct.
"Losses/Policy Loss": torch.abs(policy_loss).item(),
"Losses/Value Loss": value_loss.item(),
"Policy/Learning Rate": decay_lr,
"Policy/Epsilon": decay_eps,
"Policy/Beta": decay_bet,
}
for reward_provider in self.reward_signals.values():
update_stats.update(reward_provider.update(batch))
return update_stats
def get_modules(self):
modules = {"Optimizer": self.optimizer}
for reward_provider in self.reward_signals.values():
modules.update(reward_provider.get_modules())
return modules
class TorchSACOptimizer(TorchOptimizer):
class PolicyValueNetwork(nn.Module):
def __init__(
self,
stream_names: List[str],
observation_shapes: List[Tuple[int, ...]],
network_settings: NetworkSettings,
act_type: ActionType,
act_size: List[int],
):
super().__init__()
if act_type == ActionType.CONTINUOUS:
num_value_outs = 1
num_action_ins = sum(act_size)
else:
num_value_outs = sum(act_size)
num_action_ins = 0
self.q1_network = ValueNetwork(
stream_names,
observation_shapes,
network_settings,
num_action_ins,
num_value_outs,
)
self.q2_network = ValueNetwork(
stream_names,
observation_shapes,
network_settings,
num_action_ins,
num_value_outs,
)
def forward(
self,
vec_inputs: List[torch.Tensor],
vis_inputs: List[torch.Tensor],
actions: Optional[torch.Tensor] = None,
memories: Optional[torch.Tensor] = None,
sequence_length: int = 1,
) -> Tuple[Dict[str, torch.Tensor], Dict[str, torch.Tensor]]:
q1_out, _ = self.q1_network(
vec_inputs,
vis_inputs,
actions=actions,
memories=memories,
sequence_length=sequence_length,
)
q2_out, _ = self.q2_network(
vec_inputs,
vis_inputs,
actions=actions,
memories=memories,
sequence_length=sequence_length,
)
return q1_out, q2_out
def __init__(self, policy: TorchPolicy, trainer_params: TrainerSettings):
super().__init__(policy, trainer_params)
hyperparameters: SACSettings = cast(SACSettings, trainer_params.hyperparameters)
self.tau = hyperparameters.tau
self.init_entcoef = hyperparameters.init_entcoef
self.policy = policy
self.act_size = policy.act_size
policy_network_settings = policy.network_settings
self.tau = hyperparameters.tau
self.burn_in_ratio = 0.0
# Non-exposed SAC parameters
self.discrete_target_entropy_scale = 0.2 # Roughly equal to e-greedy 0.05
self.continuous_target_entropy_scale = 1.0
self.stream_names = list(self.reward_signals.keys())
# Use to reduce "survivor bonus" when using Curiosity or GAIL.
self.gammas = [_val.gamma for _val in trainer_params.reward_signals.values()]
self.use_dones_in_backup = {
name: int(not self.reward_signals[name].ignore_done)
for name in self.stream_names
}
self.value_network = TorchSACOptimizer.PolicyValueNetwork(
self.stream_names,
self.policy.behavior_spec.observation_shapes,
policy_network_settings,
self.policy.behavior_spec.action_type,
self.act_size,
)
self.target_network = ValueNetwork(
self.stream_names,
self.policy.behavior_spec.observation_shapes,
policy_network_settings,
)
ModelUtils.soft_update(
self.policy.actor_critic.critic, self.target_network, 1.0
)
self._log_ent_coef = torch.nn.Parameter(
torch.log(torch.as_tensor([self.init_entcoef] * len(self.act_size))),
requires_grad=True,
)
if self.policy.use_continuous_act:
self.target_entropy = torch.as_tensor(
-1
* self.continuous_target_entropy_scale
* np.prod(self.act_size[0]).astype(np.float32)
)
else:
self.target_entropy = [
self.discrete_target_entropy_scale * np.log(i).astype(np.float32)
for i in self.act_size
]
policy_params = list(self.policy.actor_critic.network_body.parameters()) + list(
self.policy.actor_critic.distribution.parameters()
)
value_params = list(self.value_network.parameters()) + list(
self.policy.actor_critic.critic.parameters()
)
logger.debug("value_vars")
for param in value_params:
logger.debug(param.shape)
logger.debug("policy_vars")
for param in policy_params:
logger.debug(param.shape)
self.decay_learning_rate = ModelUtils.DecayedValue(
hyperparameters.learning_rate_schedule,
hyperparameters.learning_rate,
1e-10,
self.trainer_settings.max_steps,
)
self.policy_optimizer = torch.optim.Adam(
policy_params, lr=hyperparameters.learning_rate
)
self.value_optimizer = torch.optim.Adam(
value_params, lr=hyperparameters.learning_rate
)
self.entropy_optimizer = torch.optim.Adam(
[self._log_ent_coef], lr=hyperparameters.learning_rate
)
self._move_to_device(default_device())
def _move_to_device(self, device: torch.device) -> None:
self._log_ent_coef.to(device)
self.target_network.to(device)
self.value_network.to(device)
def sac_q_loss(
self,
q1_out: Dict[str, torch.Tensor],
q2_out: Dict[str, torch.Tensor],
target_values: Dict[str, torch.Tensor],
dones: torch.Tensor,
rewards: Dict[str, torch.Tensor],
loss_masks: torch.Tensor,
) -> Tuple[torch.Tensor, torch.Tensor]:
q1_losses = []
q2_losses = []
# Multiple q losses per stream
for i, name in enumerate(q1_out.keys()):
q1_stream = q1_out[name].squeeze()
q2_stream = q2_out[name].squeeze()
with torch.no_grad():
q_backup = rewards[name] + (
(1.0 - self.use_dones_in_backup[name] * dones)
* self.gammas[i]
* target_values[name]
)
_q1_loss = 0.5 * ModelUtils.masked_mean(
torch.nn.functional.mse_loss(q_backup, q1_stream), loss_masks
)
_q2_loss = 0.5 * ModelUtils.masked_mean(
torch.nn.functional.mse_loss(q_backup, q2_stream), loss_masks
)
q1_losses.append(_q1_loss)
q2_losses.append(_q2_loss)
q1_loss = torch.mean(torch.stack(q1_losses))
q2_loss = torch.mean(torch.stack(q2_losses))
return q1_loss, q2_loss
def sac_value_loss(
self,
log_probs: torch.Tensor,
values: Dict[str, torch.Tensor],
q1p_out: Dict[str, torch.Tensor],
q2p_out: Dict[str, torch.Tensor],
loss_masks: torch.Tensor,
discrete: bool,
) -> torch.Tensor:
min_policy_qs = {}
with torch.no_grad():
_ent_coef = torch.exp(self._log_ent_coef)
for name in values.keys():
if not discrete:
min_policy_qs[name] = torch.min(q1p_out[name], q2p_out[name])
else:
action_probs = log_probs.exp()
_branched_q1p = ModelUtils.break_into_branches(
q1p_out[name] * action_probs, self.act_size
)
_branched_q2p = ModelUtils.break_into_branches(
q2p_out[name] * action_probs, self.act_size
)
_q1p_mean = torch.mean(
torch.stack(
[
torch.sum(_br, dim=1, keepdim=True)
for _br in _branched_q1p
]
),
dim=0,
)
_q2p_mean = torch.mean(
torch.stack(
[
torch.sum(_br, dim=1, keepdim=True)
for _br in _branched_q2p
]
),
dim=0,
)
min_policy_qs[name] = torch.min(_q1p_mean, _q2p_mean)
value_losses = []
if not discrete:
for name in values.keys():
with torch.no_grad():
v_backup = min_policy_qs[name] - torch.sum(
_ent_coef * log_probs, dim=1
)
value_loss = 0.5 * ModelUtils.masked_mean(
torch.nn.functional.mse_loss(values[name], v_backup), loss_masks
)
value_losses.append(value_loss)
else:
branched_per_action_ent = ModelUtils.break_into_branches(
log_probs * log_probs.exp(), self.act_size
)
# We have to do entropy bonus per action branch
branched_ent_bonus = torch.stack(
[
torch.sum(_ent_coef[i] * _lp, dim=1, keepdim=True)
for i, _lp in enumerate(branched_per_action_ent)
]
)
for name in values.keys():
with torch.no_grad():
v_backup = min_policy_qs[name] - torch.mean(
branched_ent_bonus, axis=0
)
value_loss = 0.5 * ModelUtils.masked_mean(
torch.nn.functional.mse_loss(values[name], v_backup.squeeze()),
loss_masks,
)
value_losses.append(value_loss)
value_loss = torch.mean(torch.stack(value_losses))
if torch.isinf(value_loss).any() or torch.isnan(value_loss).any():
raise UnityTrainerException("Inf found")
return value_loss
def sac_policy_loss(
self,
log_probs: torch.Tensor,
q1p_outs: Dict[str, torch.Tensor],
loss_masks: torch.Tensor,
discrete: bool,
) -> torch.Tensor:
_ent_coef = torch.exp(self._log_ent_coef)
mean_q1 = torch.mean(torch.stack(list(q1p_outs.values())), axis=0)
if not discrete:
mean_q1 = mean_q1.unsqueeze(1)
batch_policy_loss = torch.mean(_ent_coef * log_probs - mean_q1, dim=1)
policy_loss = ModelUtils.masked_mean(batch_policy_loss, loss_masks)
else:
action_probs = log_probs.exp()
branched_per_action_ent = ModelUtils.break_into_branches(
log_probs * action_probs, self.act_size
)
branched_q_term = ModelUtils.break_into_branches(
mean_q1 * action_probs, self.act_size
)
branched_policy_loss = torch.stack(
[
torch.sum(_ent_coef[i] * _lp - _qt, dim=1, keepdim=True)
for i, (_lp, _qt) in enumerate(
zip(branched_per_action_ent, branched_q_term)
)
]
)
batch_policy_loss = torch.squeeze(branched_policy_loss)
policy_loss = torch.mean(loss_masks * batch_policy_loss)
return policy_loss
def sac_entropy_loss(
self, log_probs: torch.Tensor, loss_masks: torch.Tensor, discrete: bool
) -> torch.Tensor:
if not discrete:
with torch.no_grad():
target_current_diff = torch.sum(log_probs + self.target_entropy, dim=1)
entropy_loss = -torch.mean(
self._log_ent_coef * loss_masks * target_current_diff
)
else:
with torch.no_grad():
branched_per_action_ent = ModelUtils.break_into_branches(
log_probs * log_probs.exp(), self.act_size
)
target_current_diff_branched = torch.stack(
[
torch.sum(_lp, axis=1, keepdim=True) + _te
for _lp, _te in zip(
branched_per_action_ent, self.target_entropy
)
],
axis=1,
)
target_current_diff = torch.squeeze(
target_current_diff_branched, axis=2
)
entropy_loss = -1 * ModelUtils.masked_mean(
torch.mean(self._log_ent_coef * target_current_diff, axis=1), loss_masks
)
return entropy_loss
def _condense_q_streams(
self, q_output: Dict[str, torch.Tensor], discrete_actions: torch.Tensor
) -> Dict[str, torch.Tensor]:
condensed_q_output = {}
onehot_actions = ModelUtils.actions_to_onehot(discrete_actions, self.act_size)
for key, item in q_output.items():
branched_q = ModelUtils.break_into_branches(item, self.act_size)
only_action_qs = torch.stack(
[
torch.sum(_act * _q, dim=1, keepdim=True)
for _act, _q in zip(onehot_actions, branched_q)
]
)
condensed_q_output[key] = torch.mean(only_action_qs, dim=0)
return condensed_q_output
@timed
def update(self, batch: AgentBuffer, num_sequences: int) -> Dict[str, float]:
"""
Updates model using buffer.
:param num_sequences: Number of trajectories in batch.
:param batch: Experience mini-batch.
:param update_target: Whether or not to update target value network
:param reward_signal_batches: Minibatches to use for updating the reward signals,
indexed by name. If none, don't update the reward signals.
:return: Output from update process.
"""
rewards = {}
for name in self.reward_signals:
rewards[name] = ModelUtils.list_to_tensor(batch[f"{name}_rewards"])
vec_obs = [ModelUtils.list_to_tensor(batch["vector_obs"])]
next_vec_obs = [ModelUtils.list_to_tensor(batch["next_vector_in"])]
act_masks = ModelUtils.list_to_tensor(batch["action_mask"])
if self.policy.use_continuous_act:
actions = ModelUtils.list_to_tensor(batch["actions"]).unsqueeze(-1)
else:
actions = ModelUtils.list_to_tensor(batch["actions"], dtype=torch.long)
memories_list = [
ModelUtils.list_to_tensor(batch["memory"][i])
for i in range(0, len(batch["memory"]), self.policy.sequence_length)
]
# LSTM shouldn't have sequence length <1, but stop it from going out of the index if true.
offset = 1 if self.policy.sequence_length > 1 else 0
next_memories_list = [
ModelUtils.list_to_tensor(
batch["memory"][i][self.policy.m_size // 2 :]
) # only pass value part of memory to target network
for i in range(offset, len(batch["memory"]), self.policy.sequence_length)
]
if len(memories_list) > 0:
memories = torch.stack(memories_list).unsqueeze(0)
next_memories = torch.stack(next_memories_list).unsqueeze(0)
else:
memories = None
next_memories = None
# Q network memories are 0'ed out, since we don't have them during inference.
q_memories = (
torch.zeros_like(next_memories) if next_memories is not None else None
)
vis_obs: List[torch.Tensor] = []
next_vis_obs: List[torch.Tensor] = []
if self.policy.use_vis_obs:
vis_obs = []
for idx, _ in enumerate(
self.policy.actor_critic.network_body.visual_processors
):
vis_ob = ModelUtils.list_to_tensor(batch["visual_obs%d" % idx])
vis_obs.append(vis_ob)
next_vis_ob = ModelUtils.list_to_tensor(
batch["next_visual_obs%d" % idx]
)
next_vis_obs.append(next_vis_ob)
# Copy normalizers from policy
self.value_network.q1_network.network_body.copy_normalization(
self.policy.actor_critic.network_body
)
self.value_network.q2_network.network_body.copy_normalization(
self.policy.actor_critic.network_body
)
self.target_network.network_body.copy_normalization(
self.policy.actor_critic.network_body
)
(sampled_actions, log_probs, _, _) = self.policy.sample_actions(
vec_obs,
vis_obs,
masks=act_masks,
memories=memories,
seq_len=self.policy.sequence_length,
all_log_probs=not self.policy.use_continuous_act,
)
value_estimates, _ = self.policy.actor_critic.critic_pass(
vec_obs, vis_obs, memories, sequence_length=self.policy.sequence_length
)
if self.policy.use_continuous_act:
squeezed_actions = actions.squeeze(-1)
q1p_out, q2p_out = self.value_network(
vec_obs,
vis_obs,
sampled_actions,
memories=q_memories,
sequence_length=self.policy.sequence_length,
)
q1_out, q2_out = self.value_network(
vec_obs,
vis_obs,
squeezed_actions,
memories=q_memories,
sequence_length=self.policy.sequence_length,
)
q1_stream, q2_stream = q1_out, q2_out
else:
with torch.no_grad():
q1p_out, q2p_out = self.value_network(
vec_obs,
vis_obs,
memories=q_memories,
sequence_length=self.policy.sequence_length,
)
q1_out, q2_out = self.value_network(
vec_obs,
vis_obs,
memories=q_memories,
sequence_length=self.policy.sequence_length,
)
q1_stream = self._condense_q_streams(q1_out, actions)
q2_stream = self._condense_q_streams(q2_out, actions)
with torch.no_grad():
target_values, _ = self.target_network(
next_vec_obs,
next_vis_obs,
memories=next_memories,
sequence_length=self.policy.sequence_length,
)
masks = ModelUtils.list_to_tensor(batch["masks"], dtype=torch.bool)
use_discrete = not self.policy.use_continuous_act
dones = ModelUtils.list_to_tensor(batch["done"])
q1_loss, q2_loss = self.sac_q_loss(
q1_stream, q2_stream, target_values, dones, rewards, masks
)
value_loss = self.sac_value_loss(
log_probs, value_estimates, q1p_out, q2p_out, masks, use_discrete
)
policy_loss = self.sac_policy_loss(log_probs, q1p_out, masks, use_discrete)
entropy_loss = self.sac_entropy_loss(log_probs, masks, use_discrete)
total_value_loss = q1_loss + q2_loss + value_loss
decay_lr = self.decay_learning_rate.get_value(self.policy.get_current_step())
ModelUtils.update_learning_rate(self.policy_optimizer, decay_lr)
self.policy_optimizer.zero_grad()
policy_loss.backward()
self.policy_optimizer.step()
ModelUtils.update_learning_rate(self.value_optimizer, decay_lr)
self.value_optimizer.zero_grad()
total_value_loss.backward()
self.value_optimizer.step()
ModelUtils.update_learning_rate(self.entropy_optimizer, decay_lr)
self.entropy_optimizer.zero_grad()
entropy_loss.backward()
self.entropy_optimizer.step()
# Update target network
ModelUtils.soft_update(
self.policy.actor_critic.critic, self.target_network, self.tau
)
update_stats = {
"Losses/Policy Loss": policy_loss.item(),
"Losses/Value Loss": value_loss.item(),
"Losses/Q1 Loss": q1_loss.item(),
"Losses/Q2 Loss": q2_loss.item(),
"Policy/Entropy Coeff": torch.mean(torch.exp(self._log_ent_coef)).item(),
"Policy/Learning Rate": decay_lr,
}
return update_stats
def update_reward_signals(
self, reward_signal_minibatches: Mapping[str, AgentBuffer], num_sequences: int
) -> Dict[str, float]:
update_stats: Dict[str, float] = {}
for name, update_buffer in reward_signal_minibatches.items():
update_stats.update(self.reward_signals[name].update(update_buffer))
return update_stats
def get_modules(self):
modules = {
"Optimizer:value_network": self.value_network,
"Optimizer:target_network": self.target_network,
"Optimizer:policy_optimizer": self.policy_optimizer,
"Optimizer:value_optimizer": self.value_optimizer,
"Optimizer:entropy_optimizer": self.entropy_optimizer,
}
for reward_provider in self.reward_signals.values():
modules.update(reward_provider.get_modules())
return modules