def _compute_target_values(self, exp_batch):
batch_next_state = exp_batch["next_state"]
with evaluating(self.model):
if self.recurrent:
next_qout, _ = pack_and_forward(
self.model,
batch_next_state,
exp_batch["next_recurrent_state"],
)
else:
next_qout = self.model(batch_next_state)
if self.recurrent:
target_next_qout, _ = pack_and_forward(
self.target_model,
batch_next_state,
exp_batch["next_recurrent_state"],
)
else:
target_next_qout = self.target_model(batch_next_state)
next_q_max = target_next_qout.evaluate_actions(
next_qout.greedy_actions)
batch_rewards = exp_batch["reward"]
batch_terminal = exp_batch["is_state_terminal"]
discount = exp_batch["discount"]
return batch_rewards + discount * (1.0 - batch_terminal) * next_q_max
def _compute_y_and_t(self, exp_batch):
batch_state = exp_batch["state"]
batch_size = len(exp_batch["reward"])
if self.recurrent:
qout, _ = pack_and_forward(
self.model,
batch_state,
exp_batch["recurrent_state"],
)
else:
qout = self.model(batch_state)
batch_actions = exp_batch["action"]
batch_q = qout.evaluate_actions(batch_actions)
# Compute target values
batch_next_state = exp_batch["next_state"]
with torch.no_grad():
if self.recurrent:
target_qout, _ = pack_and_forward(
self.target_model,
batch_state,
exp_batch["recurrent_state"],
)
target_next_qout, _ = pack_and_forward(
self.target_model,
batch_next_state,
exp_batch["next_recurrent_state"],
)
else:
target_qout = self.target_model(batch_state)
target_next_qout = self.target_model(batch_next_state)
next_q_max = torch.reshape(target_next_qout.max, (batch_size, ))
batch_rewards = exp_batch["reward"]
batch_terminal = exp_batch["is_state_terminal"]
# T Q: Bellman operator
t_q = (batch_rewards + exp_batch["discount"] *
(1.0 - batch_terminal) * next_q_max)
# T_PAL Q: persistent advantage learning operator
cur_advantage = torch.reshape(
target_qout.compute_advantage(batch_actions), (batch_size, ))
next_advantage = torch.reshape(
target_next_qout.compute_advantage(batch_actions),
(batch_size, ))
tpal_q = t_q + self.alpha * torch.max(cur_advantage,
next_advantage)
return batch_q, tpal_q
def _add_log_prob_and_value_to_episodes_recurrent(
episodes,
model,
phi,
batch_states,
obs_normalizer,
device,
):
# Sort desc by lengths so that pack_sequence does not change the order
episodes = sorted(episodes, key=len, reverse=True)
# Prepare data for a recurrent model
seqs_states = []
seqs_next_states = []
for ep in episodes:
states = batch_states([transition["state"] for transition in ep],
device, phi)
next_states = batch_states(
[transition["next_state"] for transition in ep], device, phi)
if obs_normalizer:
states = obs_normalizer(states, update=False)
next_states = obs_normalizer(next_states, update=False)
seqs_states.append(states)
seqs_next_states.append(next_states)
flat_transitions = flatten_sequences_time_first(episodes)
# Predict values using a recurrent model
with torch.no_grad(), pfrl.utils.evaluating(model):
rs = concatenate_recurrent_states(
[ep[0]["recurrent_state"] for ep in episodes])
next_rs = concatenate_recurrent_states(
[ep[0]["next_recurrent_state"] for ep in episodes])
assert (rs is None) or (next_rs is None) or (len(rs) == len(next_rs))
(flat_distribs, flat_vs), _ = pack_and_forward(model, seqs_states, rs)
(_, flat_next_vs), _ = pack_and_forward(model, seqs_next_states,
next_rs)
flat_actions = torch.tensor([b["action"] for b in flat_transitions],
device=device)
flat_log_probs = flat_distribs.log_prob(flat_actions).cpu().numpy()
flat_vs = flat_vs.cpu().numpy()
flat_next_vs = flat_next_vs.cpu().numpy()
# Add predicted values to transitions
for transition, log_prob, v, next_v in zip(flat_transitions,
flat_log_probs, flat_vs,
flat_next_vs):
transition["log_prob"] = float(log_prob)
transition["v_pred"] = float(v)
transition["next_v_pred"] = float(next_v)
def _compute_y_and_t(self, exp_batch):
"""Compute a batch of predicted/target return distributions."""
batch_size = exp_batch["reward"].shape[0]
# Compute Q-values for current states
batch_state = exp_batch["state"]
# (batch_size, n_actions, n_atoms)
if self.recurrent:
qout, _ = pack_and_forward(self.model, batch_state,
exp_batch["recurrent_state"])
else:
qout = self.model(batch_state)
n_atoms = qout.z_values.size()[0]
batch_actions = exp_batch["action"]
batch_q = qout.evaluate_actions_as_distribution(batch_actions)
assert batch_q.shape == (batch_size, n_atoms)
with torch.no_grad():
batch_q_target = self._compute_target_values(exp_batch)
assert batch_q_target.shape == (batch_size, n_atoms)
batch_q_scalars = qout.evaluate_actions(batch_actions)
self.q_record.extend(batch_q_scalars.detach().cpu().numpy().ravel())
return batch_q, batch_q_target
def _update_vf_once_recurrent(self, episodes):
# Sort episodes desc by length for pack_sequence
episodes = sorted(episodes, key=len, reverse=True)
flat_transitions = flatten_sequences_time_first(episodes)
# Prepare data for a recurrent model
seqs_states = []
for ep in episodes:
states = self.batch_states(
[transition["state"] for transition in ep], self.device,
self.phi)
if self.obs_normalizer:
states = self.obs_normalizer(states, update=False)
seqs_states.append(states)
flat_vs_teacher = torch.as_tensor(
[[transition["v_teacher"]] for transition in flat_transitions],
device=self.device,
dtype=torch.float,
)
with torch.no_grad():
vf_rs = concatenate_recurrent_states(
_collect_first_recurrent_states_of_vf(episodes))
flat_vs_pred, _ = pack_and_forward(self.vf, seqs_states, vf_rs)
vf_loss = F.mse_loss(flat_vs_pred, flat_vs_teacher)
self.vf.zero_grad()
vf_loss.backward()
if self.max_grad_norm is not None:
clip_l2_grad_norm_(self.vf.parameters(), self.max_grad_norm)
self.vf_optimizer.step()
def _compute_target_values(self, exp_batch):
"""Compute a batch of target return distributions."""
batch_next_state = exp_batch["next_state"]
if self.recurrent:
target_next_qout, _ = pack_and_forward(
self.target_model,
batch_next_state,
exp_batch["next_recurrent_state"],
)
else:
target_next_qout = self.target_model(batch_next_state)
batch_rewards = exp_batch["reward"]
batch_terminal = exp_batch["is_state_terminal"]
batch_size = exp_batch["reward"].shape[0]
z_values = target_next_qout.z_values
n_atoms = z_values.size()[0]
# next_q_max: (batch_size, n_atoms)
next_q_max = target_next_qout.max_as_distribution.detach()
assert next_q_max.shape == (batch_size, n_atoms), next_q_max.shape
# Tz: (batch_size, n_atoms)
Tz = (batch_rewards[..., None] + (1.0 - batch_terminal[..., None]) *
torch.unsqueeze(exp_batch["discount"], 1) * z_values[None])
return _apply_categorical_projection(Tz, next_q_max, z_values)
def _compute_y_and_taus(self, exp_batch):
"""Compute a batch of predicted return distributions.
Returns:
torch.Tensor: Predicted return distributions.
(batch_size, N).
"""
batch_size = exp_batch["reward"].shape[0]
# Compute Q-values for current states
batch_state = exp_batch["state"]
# (batch_size, n_actions, n_atoms)
if self.recurrent:
tau2av, _ = pack_and_forward(
self.model,
batch_state,
exp_batch["recurrent_state"],
)
else:
tau2av = self.model(batch_state)
taus = torch.rand(
batch_size,
self.quantile_thresholds_N,
device=self.device,
dtype=torch.float,
)
av = tau2av(taus)
batch_actions = exp_batch["action"]
y = av.evaluate_actions_as_quantiles(batch_actions)
self.q_record.extend(av.q_values.detach().cpu().numpy().ravel())
return y, taus
def _compute_y_and_t(self, exp_batch):
batch_state = exp_batch["state"]
batch_size = len(exp_batch["reward"])
if self.recurrent:
qout, _ = pack_and_forward(
self.model,
batch_state,
exp_batch["recurrent_state"],
)
else:
qout = self.model(batch_state)
batch_actions = exp_batch["action"]
# Q(s_t,a_t)
batch_q = qout.evaluate_actions(batch_actions).reshape((batch_size, 1))
with torch.no_grad():
# Compute target values
if self.recurrent:
target_qout, _ = pack_and_forward(
self.target_model,
batch_state,
exp_batch["recurrent_state"],
)
else:
target_qout = self.target_model(batch_state)
# Q'(s_t,a_t)
target_q = target_qout.evaluate_actions(batch_actions).reshape(
(batch_size, 1))
# LQ'(s_t,a)
target_q_expect = self._l_operator(target_qout).reshape(
(batch_size, 1))
# r + g * LQ'(s_{t+1},a)
batch_q_target = self._compute_target_values(exp_batch).reshape(
(batch_size, 1))
# Q'(s_t,a_t) + r + g * LQ'(s_{t+1},a) - LQ'(s_t,a)
t = target_q + batch_q_target - target_q_expect
return batch_q, t
def _compute_target_values(self, exp_batch):
"""Compute a batch of target return distributions."""
batch_next_state = exp_batch["next_state"]
batch_rewards = exp_batch["reward"]
batch_terminal = exp_batch["is_state_terminal"]
with pfrl.utils.evaluating(self.target_model), pfrl.utils.evaluating(
self.model):
if self.recurrent:
target_next_qout, _ = pack_and_forward(
self.target_model,
batch_next_state,
exp_batch["next_recurrent_state"],
)
next_qout, _ = pack_and_forward(
self.model,
batch_next_state,
exp_batch["next_recurrent_state"],
)
else:
target_next_qout = self.target_model(batch_next_state)
next_qout = self.model(batch_next_state)
batch_size = batch_rewards.shape[0]
z_values = target_next_qout.z_values
n_atoms = z_values.numel()
# next_q_max: (batch_size, n_atoms)
next_q_max = target_next_qout.evaluate_actions_as_distribution(
next_qout.greedy_actions.detach())
assert next_q_max.shape == (batch_size, n_atoms), next_q_max.shape
# Tz: (batch_size, n_atoms)
Tz = (batch_rewards[..., None] + (1.0 - batch_terminal[..., None]) *
exp_batch["discount"][..., None] * z_values[None])
# Tz = (
# batch_rewards.squeeze(dim=-1)
# + (1.0 - batch_terminal.unsqueeze(dim=-1))
# * exp_batch["discount"].unsqueeze(dim=-1)
# * z_values.unsqueeze(dim=0)
# )
return _apply_categorical_projection(Tz, next_q_max, z_values)
def _compute_target_values(self, exp_batch):
"""Compute a batch of target return distributions.
Returns:
torch.Tensor: (batch_size, N_prime).
"""
batch_next_state = exp_batch["next_state"]
batch_size = len(exp_batch["reward"])
taus_tilde = torch.rand(
batch_size,
self.quantile_thresholds_K,
device=self.device,
dtype=torch.float,
)
if self.recurrent:
target_next_tau2av, _ = pack_and_forward(
self.target_model,
batch_next_state,
exp_batch["next_recurrent_state"],
)
else:
target_next_tau2av = self.target_model(batch_next_state)
greedy_actions = target_next_tau2av(taus_tilde).greedy_actions
taus_prime = torch.rand(
batch_size,
self.quantile_thresholds_N_prime,
device=self.device,
dtype=torch.float,
)
target_next_maxz = target_next_tau2av(
taus_prime).evaluate_actions_as_quantiles(greedy_actions)
batch_rewards = exp_batch["reward"]
batch_terminal = exp_batch["is_state_terminal"]
batch_discount = exp_batch["discount"]
assert batch_rewards.shape == (batch_size, )
assert batch_terminal.shape == (batch_size, )
assert batch_discount.shape == (batch_size, )
batch_rewards = batch_rewards.unsqueeze(-1)
batch_terminal = batch_terminal.unsqueeze(-1)
batch_discount = batch_discount.unsqueeze(-1)
return (batch_rewards + batch_discount *
(1.0 - batch_terminal) * target_next_maxz)
def _compute_target_values(self, exp_batch):
batch_next_state = exp_batch["next_state"]
if self.recurrent:
target_next_qout, _ = pack_and_forward(
self.target_model, batch_next_state, exp_batch["next_recurrent_state"],
)
else:
target_next_qout = self.target_model(batch_next_state)
next_q_expect = self._l_operator(target_next_qout)
batch_rewards = exp_batch["reward"]
batch_terminal = exp_batch["is_state_terminal"]
return (
batch_rewards + exp_batch["discount"] * (1 - batch_terminal) * next_q_expect
)
def _compute_target_values(self, exp_batch):
batch_next_state = exp_batch["next_state"]
if self.recurrent:
target_next_qout, _ = pack_and_forward(
self.target_model,
batch_next_state,
exp_batch["next_recurrent_state"],
)
else:
target_next_qout = self.target_model(batch_next_state)
next_q_max = target_next_qout.max
batch_terminal = exp_batch["is_state_terminal"]
discount = exp_batch["discount"]
batch_rewards = exp_batch["reward"]
return batch_rewards + discount * (1.0 - batch_terminal) * next_q_max
def _compute_y_and_t(self, exp_batch):
batch_size = exp_batch["reward"].shape[0]
# Compute Q-values for current states
batch_state = exp_batch["state"]
if self.recurrent:
qout, _ = pack_and_forward(self.model, batch_state,
exp_batch["recurrent_state"])
else:
qout = self.model(batch_state)
batch_actions = exp_batch["action"]
batch_q = torch.reshape(qout.evaluate_actions(batch_actions),
(batch_size, 1))
with torch.no_grad():
batch_q_target = torch.reshape(
self._compute_target_values(exp_batch), (batch_size, 1))
return batch_q, batch_q_target
def evaluate_current_policy():
distrib, _ = pack_and_forward(self.policy, seqs_states, policy_rs)
return distrib
def _update_policy_recurrent(self, dataset):
"""Update the policy using a given dataset.
The policy is updated via CG and line search.
"""
# Sort episodes desc by length for pack_sequence
dataset = sorted(dataset, key=len, reverse=True)
flat_transitions = flatten_sequences_time_first(dataset)
# Prepare data for a recurrent model
seqs_states = []
for ep in dataset:
states = self.batch_states(
[transition["state"] for transition in ep],
self.device,
self.phi,
)
if self.obs_normalizer:
states = self.obs_normalizer(states, update=False)
seqs_states.append(states)
flat_actions = torch.as_tensor(
[transition["action"] for transition in flat_transitions],
device=self.device,
)
flat_advs = torch.as_tensor(
[transition["adv"] for transition in flat_transitions],
device=self.device,
dtype=torch.float,
)
if self.standardize_advantages:
std_advs, mean_advs = torch.std_mean(flat_advs, unbiased=False)
flat_advs = (flat_advs - mean_advs) / (std_advs + 1e-8)
with torch.no_grad():
policy_rs = concatenate_recurrent_states(
_collect_first_recurrent_states_of_policy(dataset)
)
flat_distribs, _ = pack_and_forward(self.policy, seqs_states, policy_rs)
log_prob_old = torch.tensor(
[transition["log_prob"] for transition in flat_transitions],
device=self.device,
dtype=torch.float,
)
gain = self._compute_gain(
log_prob=flat_distribs.log_prob(flat_actions),
log_prob_old=log_prob_old,
entropy=flat_distribs.entropy(),
advs=flat_advs,
)
# Distribution to compute KL div against
with torch.no_grad():
# torch.distributions.Distribution cannot be deepcopied
action_distrib_old, _ = pack_and_forward(
self.policy, seqs_states, policy_rs
)
full_step = self._compute_kl_constrained_step(
action_distrib=flat_distribs,
action_distrib_old=action_distrib_old,
gain=gain,
)
self._line_search(
full_step=full_step,
dataset=dataset,
advs=flat_advs,
action_distrib_old=action_distrib_old,
gain=gain,
)
def update(self, statevar):
assert self.t_start < self.t
n = self.t - self.t_start
self.assert_shared_memory()
if statevar is None:
R = 0
else:
with torch.no_grad(), pfrl.utils.evaluating(self.model):
if self.recurrent:
(_,
vout), _ = one_step_forward(self.model, statevar,
self.train_recurrent_states)
else:
_, vout = self.model(statevar)
R = float(vout)
pi_loss_factor = self.pi_loss_coef
v_loss_factor = self.v_loss_coef
# Normalize the loss of sequences truncated by terminal states
if self.keep_loss_scale_same and self.t - self.t_start < self.t_max:
factor = self.t_max / (self.t - self.t_start)
pi_loss_factor *= factor
v_loss_factor *= factor
if self.normalize_grad_by_t_max:
pi_loss_factor /= self.t - self.t_start
v_loss_factor /= self.t - self.t_start
# Batch re-compute for efficient backprop
batch_obs = self.batch_states(
[self.past_obs[i] for i in range(self.t_start, self.t)],
self.device,
self.phi,
)
if self.recurrent:
(batch_distrib, batch_v), _ = pack_and_forward(
self.model,
[batch_obs],
self.past_recurrent_state[self.t_start],
)
else:
batch_distrib, batch_v = self.model(batch_obs)
batch_action = torch.stack(
[self.past_action[i] for i in range(self.t_start, self.t)])
batch_log_prob = batch_distrib.log_prob(batch_action)
batch_entropy = batch_distrib.entropy()
rev_returns = []
for i in reversed(range(self.t_start, self.t)):
R *= self.gamma
R += self.past_rewards[i]
rev_returns.append(R)
batch_return = torch.as_tensor(list(reversed(rev_returns)),
dtype=torch.float)
batch_adv = batch_return - batch_v.detach().squeeze(-1)
assert batch_log_prob.shape == (n, )
assert batch_adv.shape == (n, )
assert batch_entropy.shape == (n, )
pi_loss = torch.sum(-batch_adv * batch_log_prob -
self.beta * batch_entropy,
dim=0)
assert batch_v.shape == (n, 1)
assert batch_return.shape == (n, )
v_loss = F.mse_loss(batch_v, batch_return[..., None],
reduction="sum") / 2
if pi_loss_factor != 1.0:
pi_loss *= pi_loss_factor
if v_loss_factor != 1.0:
v_loss *= v_loss_factor
if self.process_idx == 0:
logger.debug("pi_loss:%s v_loss:%s", pi_loss, v_loss)
total_loss = torch.squeeze(pi_loss) + torch.squeeze(v_loss)
# Compute gradients using thread-specific model
self.model.zero_grad()
total_loss.backward()
if self.max_grad_norm is not None:
clip_l2_grad_norm_(self.model.parameters(), self.max_grad_norm)
# Copy the gradients to the globally shared model
copy_param.copy_grad(target_link=self.shared_model,
source_link=self.model)
# Update the globally shared model
self.optimizer.step()
if self.process_idx == 0:
logger.debug("update")
self.sync_parameters()
self.past_obs = {}
self.past_action = {}
self.past_rewards = {}
self.past_recurrent_state = {}
self.t_start = self.t
def _update_once_recurrent(self, episodes, mean_advs, std_advs):
assert std_advs is None or std_advs > 0
device = self.device
# Sort desc by lengths so that pack_sequence does not change the order
episodes = sorted(episodes, key=len, reverse=True)
flat_transitions = flatten_sequences_time_first(episodes)
# Prepare data for a recurrent model
seqs_states = []
for ep in episodes:
states = self.batch_states(
[transition["state"] for transition in ep],
self.device,
self.phi,
)
if self.obs_normalizer:
states = self.obs_normalizer(states, update=False)
seqs_states.append(states)
flat_actions = torch.tensor(
[transition["action"] for transition in flat_transitions],
device=device,
)
flat_advs = torch.tensor(
[transition["adv"] for transition in flat_transitions],
dtype=torch.float,
device=device,
)
if self.standardize_advantages:
flat_advs = (flat_advs - mean_advs) / (std_advs + 1e-8)
flat_log_probs_old = torch.tensor(
[transition["log_prob"] for transition in flat_transitions],
dtype=torch.float,
device=device,
)
flat_vs_pred_old = torch.tensor(
[[transition["v_pred"]] for transition in flat_transitions],
dtype=torch.float,
device=device,
)
flat_vs_teacher = torch.tensor(
[[transition["v_teacher"]] for transition in flat_transitions],
dtype=torch.float,
device=device,
)
with torch.no_grad(), pfrl.utils.evaluating(self.model):
rs = concatenate_recurrent_states(
[ep[0]["recurrent_state"] for ep in episodes])
(flat_distribs,
flat_vs_pred), _ = pack_and_forward(self.model, seqs_states, rs)
flat_log_probs = flat_distribs.log_prob(flat_actions)
flat_entropy = flat_distribs.entropy()
self.model.zero_grad()
loss = self._lossfun(
entropy=flat_entropy,
vs_pred=flat_vs_pred,
log_probs=flat_log_probs,
vs_pred_old=flat_vs_pred_old,
log_probs_old=flat_log_probs_old,
advs=flat_advs,
vs_teacher=flat_vs_teacher,
)
loss.backward()
if self.max_grad_norm is not None:
torch.nn.utils.clip_grad_norm_(self.model.parameters(),
self.max_grad_norm)
self.optimizer.step()
self.n_updates += 1
