def create_forward_model(
self, encoded_state: tf.Tensor, encoded_next_state: tf.Tensor
) -> None:
"""
Creates forward model TensorFlow ops for Curiosity module.
Predicts encoded future state based on encoded current state and given action.
:param encoded_state: Tensor corresponding to encoded current state.
:param encoded_next_state: Tensor corresponding to encoded next state.
"""
combined_input = tf.concat(
[encoded_state, self.policy.selected_actions], axis=1
)
hidden = tf.layers.dense(combined_input, 256, activation=ModelUtils.swish)
pred_next_state = tf.layers.dense(
hidden,
self.encoding_size
* (self.policy.vis_obs_size + int(self.policy.vec_obs_size > 0)),
activation=None,
)
squared_difference = 0.5 * tf.reduce_sum(
tf.squared_difference(pred_next_state, encoded_next_state), axis=1
)
self.intrinsic_reward = squared_difference
self.forward_loss = tf.reduce_mean(
tf.dynamic_partition(squared_difference, self.policy.mask, 2)[1]
)
def create_loss(self, learning_rate: float, anneal_steps: int) -> None:
"""
Creates the loss and update nodes for the BC module
:param learning_rate: The learning rate for the optimizer
:param anneal_steps: Number of steps over which to anneal the learning_rate
"""
selected_action = self.policy.output
if self.policy.use_continuous_act:
self.loss = tf.reduce_mean(
tf.squared_difference(selected_action, self.expert_action))
else:
log_probs = self.policy.all_log_probs
self.loss = tf.reduce_mean(
-tf.log(tf.nn.softmax(log_probs) + 1e-7) * self.expert_action)
if anneal_steps > 0:
self.annealed_learning_rate = tf.train.polynomial_decay(
learning_rate,
self.policy.global_step,
anneal_steps,
0.0,
power=1.0)
else:
self.annealed_learning_rate = tf.Variable(learning_rate)
optimizer = tf.train.AdamOptimizer(
learning_rate=self.annealed_learning_rate, name="bc_adam")
self.update_batch = optimizer.minimize(self.loss)
def create_inverse_model(self, encoded_state: tf.Tensor,
encoded_next_state: tf.Tensor) -> None:
"""
Creates inverse model TensorFlow ops for Curiosity module.
Predicts action taken given current and future encoded states.
:param encoded_state: Tensor corresponding to encoded current state.
:param encoded_next_state: Tensor corresponding to encoded next state.
"""
combined_input = tf.concat([encoded_state, encoded_next_state], axis=1)
hidden = tf.layers.dense(combined_input,
256,
activation=LearningModel.swish)
if self.policy_model.brain.vector_action_space_type == "continuous":
pred_action = tf.layers.dense(hidden,
self.policy_model.act_size[0],
activation=None)
squared_difference = tf.reduce_sum(
tf.squared_difference(pred_action,
self.policy_model.selected_actions),
axis=1,
)
self.inverse_loss = tf.reduce_mean(
tf.dynamic_partition(squared_difference,
self.policy_model.mask, 2)[1])
else:
pred_action = tf.concat(
[
tf.layers.dense(hidden,
self.policy_model.act_size[i],
activation=tf.nn.softmax)
for i in range(len(self.policy_model.act_size))
],
axis=1,
)
cross_entropy = tf.reduce_sum(
-tf.log(pred_action + 1e-10) *
self.policy_model.selected_actions,
axis=1,
)
self.inverse_loss = tf.reduce_mean(
tf.dynamic_partition(cross_entropy, self.policy_model.mask,
2)[1])
def _create_losses(self, probs, old_probs, value_heads, entropy, beta,
epsilon, lr, max_step):
"""
Creates training-specific Tensorflow ops for PPO models.
:param probs: Current policy probabilities
:param old_probs: Past policy probabilities
:param value_heads: Value estimate tensors from each value stream
:param beta: Entropy regularization strength
:param entropy: Current policy entropy
:param epsilon: Value for policy-divergence threshold
:param lr: Learning rate
:param max_step: Total number of training steps.
"""
self.returns_holders = {}
self.old_values = {}
for name in value_heads.keys():
returns_holder = tf.placeholder(shape=[None],
dtype=tf.float32,
name="{}_returns".format(name))
old_value = tf.placeholder(shape=[None],
dtype=tf.float32,
name="{}_value_estimate".format(name))
self.returns_holders[name] = returns_holder
self.old_values[name] = old_value
self.advantage = tf.placeholder(shape=[None],
dtype=tf.float32,
name="advantages")
advantage = tf.expand_dims(self.advantage, -1)
decay_epsilon = tf.train.polynomial_decay(epsilon,
self.policy.global_step,
max_step,
0.1,
power=1.0)
decay_beta = tf.train.polynomial_decay(beta,
self.policy.global_step,
max_step,
1e-5,
power=1.0)
value_losses = []
for name, head in value_heads.items():
clipped_value_estimate = self.old_values[name] + tf.clip_by_value(
tf.reduce_sum(head, axis=1) - self.old_values[name],
-decay_epsilon,
decay_epsilon,
)
v_opt_a = tf.squared_difference(self.returns_holders[name],
tf.reduce_sum(head, axis=1))
v_opt_b = tf.squared_difference(self.returns_holders[name],
clipped_value_estimate)
value_loss = tf.reduce_mean(
tf.dynamic_partition(tf.maximum(v_opt_a, v_opt_b),
self.policy.mask, 2)[1])
value_losses.append(value_loss)
self.value_loss = tf.reduce_mean(value_losses)
r_theta = tf.exp(probs - old_probs)
p_opt_a = r_theta * advantage
p_opt_b = (tf.clip_by_value(r_theta, 1.0 - decay_epsilon,
1.0 + decay_epsilon) * advantage)
self.policy_loss = -tf.reduce_mean(
tf.dynamic_partition(tf.minimum(p_opt_a, p_opt_b),
self.policy.mask, 2)[1])
# For cleaner stats reporting
self.abs_policy_loss = tf.abs(self.policy_loss)
self.loss = (
self.policy_loss + 0.5 * self.value_loss -
decay_beta * tf.reduce_mean(
tf.dynamic_partition(entropy, self.policy.mask, 2)[1]))
def _create_losses(
self,
q1_streams: Dict[str, tf.Tensor],
q2_streams: Dict[str, tf.Tensor],
lr: tf.Tensor,
max_step: int,
stream_names: List[str],
discrete: bool = False,
) -> None:
"""
Creates training-specific Tensorflow ops for SAC models.
:param q1_streams: Q1 streams from policy network
:param q1_streams: Q2 streams from policy network
:param lr: Learning rate
:param max_step: Total number of training steps.
:param stream_names: List of reward stream names.
:param discrete: Whether or not to use discrete action losses.
"""
if discrete:
self.target_entropy = [
self.discrete_target_entropy_scale *
np.log(i).astype(np.float32) for i in self.act_size
]
discrete_action_probs = tf.exp(self.policy.all_log_probs)
per_action_entropy = discrete_action_probs * self.policy.all_log_probs
else:
self.target_entropy = (
-1 * self.continuous_target_entropy_scale *
np.prod(self.act_size[0]).astype(np.float32))
self.rewards_holders = {}
self.min_policy_qs = {}
for name in stream_names:
if discrete:
_branched_mpq1 = ModelUtils.break_into_branches(
self.policy_network.q1_pheads[name] *
discrete_action_probs,
self.act_size,
)
branched_mpq1 = tf.stack([
tf.reduce_sum(_br, axis=1, keep_dims=True)
for _br in _branched_mpq1
])
_q1_p_mean = tf.reduce_mean(branched_mpq1, axis=0)
_branched_mpq2 = ModelUtils.break_into_branches(
self.policy_network.q2_pheads[name] *
discrete_action_probs,
self.act_size,
)
branched_mpq2 = tf.stack([
tf.reduce_sum(_br, axis=1, keep_dims=True)
for _br in _branched_mpq2
])
_q2_p_mean = tf.reduce_mean(branched_mpq2, axis=0)
self.min_policy_qs[name] = tf.minimum(_q1_p_mean, _q2_p_mean)
else:
self.min_policy_qs[name] = tf.minimum(
self.policy_network.q1_pheads[name],
self.policy_network.q2_pheads[name],
)
rewards_holder = tf.placeholder(shape=[None],
dtype=tf.float32,
name=f"{name}_rewards")
self.rewards_holders[name] = rewards_holder
q1_losses = []
q2_losses = []
# Multiple q losses per stream
expanded_dones = tf.expand_dims(self.dones_holder, axis=-1)
for i, name in enumerate(stream_names):
_expanded_rewards = tf.expand_dims(self.rewards_holders[name],
axis=-1)
q_backup = tf.stop_gradient(
_expanded_rewards +
(1.0 - self.use_dones_in_backup[name] * expanded_dones) *
self.gammas[i] * self.target_network.value_heads[name])
if discrete:
# We need to break up the Q functions by branch, and update them individually.
branched_q1_stream = ModelUtils.break_into_branches(
self.policy.selected_actions * q1_streams[name],
self.act_size)
branched_q2_stream = ModelUtils.break_into_branches(
self.policy.selected_actions * q2_streams[name],
self.act_size)
# Reduce each branch into scalar
branched_q1_stream = [
tf.reduce_sum(_branch, axis=1, keep_dims=True)
for _branch in branched_q1_stream
]
branched_q2_stream = [
tf.reduce_sum(_branch, axis=1, keep_dims=True)
for _branch in branched_q2_stream
]
q1_stream = tf.reduce_mean(branched_q1_stream, axis=0)
q2_stream = tf.reduce_mean(branched_q2_stream, axis=0)
else:
q1_stream = q1_streams[name]
q2_stream = q2_streams[name]
_q1_loss = 0.5 * tf.reduce_mean(
tf.to_float(self.policy.mask) *
tf.squared_difference(q_backup, q1_stream))
_q2_loss = 0.5 * tf.reduce_mean(
tf.to_float(self.policy.mask) *
tf.squared_difference(q_backup, q2_stream))
q1_losses.append(_q1_loss)
q2_losses.append(_q2_loss)
self.q1_loss = tf.reduce_mean(q1_losses)
self.q2_loss = tf.reduce_mean(q2_losses)
# Learn entropy coefficient
if discrete:
# Create a log_ent_coef for each branch
self.log_ent_coef = tf.get_variable(
"log_ent_coef",
dtype=tf.float32,
initializer=np.log([self.init_entcoef] *
len(self.act_size)).astype(np.float32),
trainable=True,
)
else:
self.log_ent_coef = tf.get_variable(
"log_ent_coef",
dtype=tf.float32,
initializer=np.log(self.init_entcoef).astype(np.float32),
trainable=True,
)
self.ent_coef = tf.exp(self.log_ent_coef)
if discrete:
# We also have to do a different entropy and target_entropy per branch.
branched_per_action_ent = ModelUtils.break_into_branches(
per_action_entropy, self.act_size)
branched_ent_sums = tf.stack(
[
tf.reduce_sum(_lp, axis=1, keep_dims=True) + _te for _lp,
_te in zip(branched_per_action_ent, self.target_entropy)
],
axis=1,
)
self.entropy_loss = -tf.reduce_mean(
tf.to_float(self.policy.mask) * tf.reduce_mean(
self.log_ent_coef *
tf.squeeze(tf.stop_gradient(branched_ent_sums), axis=2),
axis=1,
))
# Same with policy loss, we have to do the loss per branch and average them,
# so that larger branches don't get more weight.
# The equivalent KL divergence from Eq 10 of Haarnoja et al. is also pi*log(pi) - Q
branched_q_term = ModelUtils.break_into_branches(
discrete_action_probs * self.policy_network.q1_p,
self.act_size)
branched_policy_loss = tf.stack([
tf.reduce_sum(self.ent_coef[i] * _lp - _qt,
axis=1,
keep_dims=True)
for i, (_lp, _qt) in enumerate(
zip(branched_per_action_ent, branched_q_term))
])
self.policy_loss = tf.reduce_mean(
tf.to_float(self.policy.mask) *
tf.squeeze(branched_policy_loss))
# Do vbackup entropy bonus per branch as well.
branched_ent_bonus = tf.stack([
tf.reduce_sum(self.ent_coef[i] * _lp, axis=1, keep_dims=True)
for i, _lp in enumerate(branched_per_action_ent)
])
value_losses = []
for name in stream_names:
v_backup = tf.stop_gradient(
self.min_policy_qs[name] -
tf.reduce_mean(branched_ent_bonus, axis=0))
value_losses.append(0.5 * tf.reduce_mean(
tf.to_float(self.policy.mask) * tf.squared_difference(
self.policy_network.value_heads[name], v_backup)))
else:
self.entropy_loss = -tf.reduce_mean(
self.log_ent_coef * tf.to_float(self.policy.mask) *
tf.stop_gradient(
tf.reduce_sum(
self.policy.all_log_probs + self.target_entropy,
axis=1,
keep_dims=True,
)))
batch_policy_loss = tf.reduce_mean(
self.ent_coef * self.policy.all_log_probs -
self.policy_network.q1_p,
axis=1,
)
self.policy_loss = tf.reduce_mean(
tf.to_float(self.policy.mask) * batch_policy_loss)
value_losses = []
for name in stream_names:
v_backup = tf.stop_gradient(
self.min_policy_qs[name] - tf.reduce_sum(
self.ent_coef * self.policy.all_log_probs, axis=1))
value_losses.append(0.5 * tf.reduce_mean(
tf.to_float(self.policy.mask) * tf.squared_difference(
self.policy_network.value_heads[name], v_backup)))
self.value_loss = tf.reduce_mean(value_losses)
self.total_value_loss = self.q1_loss + self.q2_loss + self.value_loss
self.entropy = self.policy_network.entropy
def __init__(
self,
brain,
h_size=128,
lr=1e-4,
n_layers=2,
m_size=128,
normalize=False,
use_recurrent=False,
seed=0,
):
LearningModel.__init__(self, m_size, normalize, use_recurrent, brain, seed)
num_streams = 1
hidden_streams = self.create_observation_streams(num_streams, h_size, n_layers)
hidden = hidden_streams[0]
self.dropout_rate = tf.placeholder(
dtype=tf.float32, shape=[], name="dropout_rate"
)
hidden_reg = tf.layers.dropout(hidden, self.dropout_rate)
if self.use_recurrent:
tf.Variable(
self.m_size, name="memory_size", trainable=False, dtype=tf.int32
)
self.memory_in = tf.placeholder(
shape=[None, self.m_size], dtype=tf.float32, name="recurrent_in"
)
hidden_reg, self.memory_out = self.create_recurrent_encoder(
hidden_reg, self.memory_in, self.sequence_length
)
self.memory_out = tf.identity(self.memory_out, name="recurrent_out")
if brain.vector_action_space_type == "discrete":
policy_branches = []
for size in self.act_size:
policy_branches.append(
tf.layers.dense(
hidden_reg,
size,
activation=None,
use_bias=False,
kernel_initializer=tf.initializers.variance_scaling(0.01),
)
)
self.action_probs = tf.concat(
[tf.nn.softmax(branch) for branch in policy_branches],
axis=1,
name="action_probs",
)
self.action_masks = tf.placeholder(
shape=[None, sum(self.act_size)], dtype=tf.float32, name="action_masks"
)
self.sample_action_float, _, normalized_logits = self.create_discrete_action_masking_layer(
tf.concat(policy_branches, axis=1), self.action_masks, self.act_size
)
tf.identity(normalized_logits, name="action")
self.sample_action = tf.cast(self.sample_action_float, tf.int32)
self.true_action = tf.placeholder(
shape=[None, len(policy_branches)],
dtype=tf.int32,
name="teacher_action",
)
self.action_oh = tf.concat(
[
tf.one_hot(self.true_action[:, i], self.act_size[i])
for i in range(len(self.act_size))
],
axis=1,
)
self.loss = tf.reduce_sum(
-tf.log(self.action_probs + 1e-10) * self.action_oh
)
self.action_percent = tf.reduce_mean(
tf.cast(
tf.equal(
tf.cast(tf.argmax(self.action_probs, axis=1), tf.int32),
self.sample_action,
),
tf.float32,
)
)
else:
self.policy = tf.layers.dense(
hidden_reg,
self.act_size[0],
activation=None,
use_bias=False,
name="pre_action",
kernel_initializer=tf.initializers.variance_scaling(0.01),
)
self.clipped_sample_action = tf.clip_by_value(self.policy, -1, 1)
self.sample_action = tf.identity(self.clipped_sample_action, name="action")
self.true_action = tf.placeholder(
shape=[None, self.act_size[0]], dtype=tf.float32, name="teacher_action"
)
self.clipped_true_action = tf.clip_by_value(self.true_action, -1, 1)
self.loss = tf.reduce_sum(
tf.squared_difference(self.clipped_true_action, self.sample_action)
)
optimizer = tf.train.AdamOptimizer(learning_rate=lr)
self.update = optimizer.minimize(self.loss)
