def _build_sync_op(self):
"""Build the sync op."""
sync_count = tf.Variable(0, trainable=False)
sync_ops = [tf.assign_add(sync_count, 1)]
trainables_online = tf.get_collection(
tf.GraphKeys.TRAINABLE_VARIABLES, scope='Online')
trainables_target = tf.get_collection(
tf.GraphKeys.TRAINABLE_VARIABLES, scope='Target')
for (w_online, w_target) in zip(trainables_online, trainables_target):
sync_ops.append(w_target.assign(w_online, use_locking=True))
tf.summary.scalar('Learning/SyncCount', sync_count)
return sync_ops
def build_graph(self):
"""Builds the neural network graph."""
# define graph
self.g = tf.Graph()
with self.g.as_default():
# create and store a new session for the graph
self.sess = tf.Session()
# define placeholders
self.x = tf.placeholder(shape=[None, self.dim_input],
dtype=tf.float32)
self.y = tf.placeholder(shape=[None, self.num_classes],
dtype=tf.float32)
# define simple model
with tf.variable_scope('last_layer'):
self.z = tf.layers.dense(inputs=self.x, units=self.num_classes)
self.loss = tf.reduce_mean(
tf.nn.softmax_cross_entropy_with_logits_v2(labels=self.y,
logits=self.z))
self.output_probs = tf.nn.softmax(self.z)
# Variables of the last layer
self.ll_vars = tf.get_collection(tf.GraphKeys.TRAINABLE_VARIABLES)
self.ll_vars_concat = tf.concat(
[self.ll_vars[0],
tf.expand_dims(self.ll_vars[1], axis=0)], 0)
# Summary
_variable_summaries(self.ll_vars_concat)
# saving the weights of last layer when running bootstrap algorithm
self.saver = tf.train.Saver(var_list=self.ll_vars)
self.gd_opt = tf.train.GradientDescentOptimizer(self.step_size)
# SGD optimizer for the last layer
grads_vars_sgd = self.gd_opt.compute_gradients(self.loss)
self.train_op = self.gd_opt.apply_gradients(grads_vars_sgd)
for g, v in grads_vars_sgd:
if g is not None:
s = list(v.name)
s[v.name.rindex(':')] = '_'
tf.summary.histogram(''.join(s) + '/grad_hist_boot_sgd', g)
# Merge all the summaries and write them out
self.all_summaries = tf.summary.merge_all()
location = os.path.join(self.working_dir, 'logs')
self.writer = tf.summary.FileWriter(location, graph=self.g)
saver_network = tf.train.Saver(var_list=self.ll_vars)
print('Loading the network...')
# Restores from checkpoint
saver_network.restore(self.sess, self.model_dir)
print('Graph successfully loaded.')
def _build_sync_op(self):
"""Build ops for assigning weights from online to target network.
Returns:
ops: A list of ops assigning weights from online to target network.
"""
# Get trainable variables from online and target networks.
sync_qt_ops = []
trainables_online = tf.get_collection(tf.GraphKeys.TRAINABLE_VARIABLES,
scope='Online')
trainables_target = tf.get_collection(tf.GraphKeys.TRAINABLE_VARIABLES,
scope='Target')
for (w_online, w_target) in zip(trainables_online, trainables_target):
# Assign weights from online to target network.
sync_qt_ops.append(w_target.assign(w_online, use_locking=True))
return sync_qt_ops
def get_train_op(self, global_step):
"""Returns the operation that performs a training update."""
# UPDATE_OPS picks up batch_norm updates.
update_ops = tf.get_collection(tf.GraphKeys.UPDATE_OPS)
with tf.control_dependencies(update_ops):
train_op = self.optimizer.minimize(self.losses['train'],
global_step=global_step)
return train_op
def compute_loss(self, onehot_labels, predictions):
"""Computes the MSE loss of `predictions` with respect to `onehot_labels`.
Args:
onehot_labels: A `tf.Tensor` containing the the class labels; each vector
along the class dimension should hold a valid probability distribution.
predictions: A `tf.Tensor` containing the the class predictions,
interpreted as unnormalized log probabilities.
Returns:
A `tf.Tensor` representing the average loss.
"""
mse_loss = tf.losses.mean_squared_error(onehot_labels, predictions)
regularization = tf.reduce_sum(
tf.get_collection(tf.GraphKeys.REGULARIZATION_LOSSES))
loss = mse_loss + regularization
return loss
def train_q(dataset,
policy,
optimizer=None,
pack_transition_fn=None,
q_graph_fn=None,
log_dir=None,
master='',
task=0,
training_steps=None,
max_training_steps=100000,
reuse=False,
init_checkpoint=None,
update_target_every_n_steps=50,
log_every_n_steps=None,
save_checkpoint_steps=500,
save_summaries_steps=500):
"""Self-contained learning loop for offline Q-learning.
Code inspired by OpenAI Baselines' deepq.build_train. This function is
compatible with discrete Q-learning graphs, continuous Q learning graphs, and
SARSA.
Args:
dataset: tf.data.Dataset providing transitions.
policy: Instance of TFDQNPolicy class that provides functor for building the
critic function.
optimizer: Optional instance of an optimizer. If not specified, creates an
AdamOptimizer using the default constructor.
pack_transition_fn: Optional function that performs additional processing
of the transition. This is a convenience method for ad-hoc manipulation of
transition data passed to the learning function after parsing.
q_graph_fn: Function used to construct training objectives w.r.t. critic
outputs.
log_dir: Where to save model checkpoints and tensorboard summaries.
master: Optional address of master worker. Specify this when doing
distributed training.
task: Optional worker task for distributed training. Defaults to solo master
task on a single machine.
training_steps: Optional number of steps to run training before terminating
early. Max_training_steps remains unchanged - training will terminate
after max_training_steps whether or not training_steps is specified.
max_training_steps: maximum number of training iters.
reuse: If True, reuse existing variables for all declared variables by this
function.
init_checkpoint: Optional checkpoint to restore prior to training. If not
provided, variables are initialized using global_variables_initializer().
update_target_every_n_steps: How many global steps (training) between
copying the Q network weights (scope='q_func') to target network
(scope='target_q_func').
log_every_n_steps: How many global steps between logging loss tensors.
save_checkpoint_steps: How many global steps between saving TF variables
to a checkpoint file.
save_summaries_steps: How many global steps between saving TF summaries.
Returns:
(int) Current `global_step` reached after training for training_steps, or
`max_training_steps` if `global_step` has reached `max_training_steps`.
Raises:
ValueError: If a batch of transitions is empty or the zeroth element is
empty, when it's supposed to be of length batch_size.
"""
data_iterator = dataset.make_one_shot_iterator()
transition = data_iterator.get_next()
if pack_transition_fn:
transition = pack_transition_fn(transition)
if optimizer is None:
optimizer = tf.train.AdamOptimizer()
q_func = policy.get_q_func(is_training=True, reuse=reuse)
loss, all_summaries = q_graph_fn(q_func, transition)
q_func_vars = contrib_framework.get_trainable_variables(scope='q_func')
target_q_func_vars = contrib_framework.get_trainable_variables(
scope='target_q_func')
global_step = tf.train.get_or_create_global_step()
# Only optimize q_func and update its batchnorm params.
update_ops = tf.get_collection(tf.GraphKeys.UPDATE_OPS, scope='q_func')
with tf.control_dependencies(update_ops):
train_op = optimizer.minimize(loss,
global_step=global_step,
var_list=q_func_vars)
chief_hooks = []
hooks = []
# Save summaries periodically.
if save_summaries_steps is not None:
chief_hooks.append(
tf.train.SummarySaverHook(save_steps=save_summaries_steps,
output_dir=log_dir,
summary_op=all_summaries))
# Stop after training_steps
if max_training_steps:
hooks.append(tf.train.StopAtStepHook(last_step=max_training_steps))
# Report if loss tensor is NaN.
hooks.append(tf.train.NanTensorHook(loss))
if log_every_n_steps is not None:
tensor_dict = {'global_step': global_step, 'train loss': loss}
chief_hooks.append(
tf.train.LoggingTensorHook(tensor_dict,
every_n_iter=log_every_n_steps))
# Measure how fast we are training per sec and save to summary.
chief_hooks.append(
tf.train.StepCounterHook(every_n_steps=log_every_n_steps,
output_dir=log_dir))
# If target network exists, periodically update target Q network with new
# weights (frozen target network). We hack this by
# abusing a LoggingTensorHook for this.
if target_q_func_vars and update_target_every_n_steps is not None:
update_target_expr = []
for var, var_t in zip(sorted(q_func_vars, key=lambda v: v.name),
sorted(target_q_func_vars,
key=lambda v: v.name)):
update_target_expr.append(var_t.assign(var))
update_target_expr = tf.group(*update_target_expr)
with tf.control_dependencies([update_target_expr]):
update_target = tf.constant(0)
chief_hooks.append(
tf.train.LoggingTensorHook(
{'update_target': update_target},
every_n_iter=update_target_every_n_steps))
# Save checkpoints periodically, save all of them.
saver = tf.train.Saver(max_to_keep=None)
chief_hooks.append(
tf.train.CheckpointSaverHook(log_dir,
save_steps=save_checkpoint_steps,
saver=saver,
checkpoint_basename='model.ckpt'))
# Save our experiment params to checkpoint dir.
chief_hooks.append(
gin.tf.GinConfigSaverHook(log_dir, summarize_config=True))
session_config = tf.ConfigProto(log_device_placement=False)
init_fn = None
if init_checkpoint:
assign_fn = contrib_framework.assign_from_checkpoint_fn(
init_checkpoint, contrib_framework.get_model_variables())
init_fn = lambda _, sess: assign_fn(sess)
scaffold = tf.train.Scaffold(saver=saver, init_fn=init_fn)
with tf.train.MonitoredTrainingSession(
master=master,
is_chief=(task == 0),
config=session_config,
checkpoint_dir=log_dir,
scaffold=scaffold,
hooks=hooks,
chief_only_hooks=chief_hooks) as sess:
np_step = 0
while not sess.should_stop():
np_step, _ = sess.run([global_step, train_op])
if training_steps and np_step % training_steps == 0:
break
done = np_step >= max_training_steps
return np_step, done
def build_graph(self):
"""Builds the neural network graph."""
# define graph
self.g = tf.Graph()
with self.g.as_default():
# create and store a new session for the graph
self.sess = tf.Session()
# define placeholders
self.x = tf.placeholder(shape=[None, self.dim_input],
dtype=tf.float32)
self.y = tf.placeholder(shape=[None, self.num_classes],
dtype=tf.float32)
# linear layer(WX + b)
with tf.variable_scope('last_layer/dense') as scope:
weights = tf.get_variable('kernel',
[self.dim_input, self.num_classes],
dtype=tf.float32)
biases = tf.get_variable('bias', [self.num_classes],
dtype=tf.float32)
wb = tf.concat([weights, tf.expand_dims(biases, axis=0)], 0)
wb_renorm = tf.matmul(self.sigma_half_inv, wb)
weights_renorm = wb_renorm[:self.dim_input, :]
biases_renorm = wb_renorm[-1, :]
self.z = tf.add(tf.matmul(self.x, weights_renorm),
biases_renorm,
name=scope.name)
# Gaussian prior
# prior = tf.nn.l2_loss(weights) + tf.nn.l2_loss(biases)
# Non normalized loss, because of the preconditioning
self.loss = self.n * tf.reduce_mean(
tf.nn.softmax_cross_entropy_with_logits_v2(labels=self.y,
logits=self.z))
# Bayesian loss
self.bayesian_loss = self.loss # + prior
self.output_probs = tf.nn.softmax(self.z)
# Variables of the last layer
self.ll_vars = tf.get_collection(tf.GraphKeys.TRAINABLE_VARIABLES)
self.ll_vars_concat = tf.concat(
[self.ll_vars[0],
tf.expand_dims(self.ll_vars[1], axis=0)], 0)
# Summary
_variable_summaries(self.ll_vars_concat)
# saving the weights of last layer when running SGLD/SGD/MCMC algorithm
self.saver = tf.train.Saver(var_list=self.ll_vars,
max_to_keep=self.num_samples)
self.gd_opt = tf.train.GradientDescentOptimizer(self.step_size)
# SGLD optimizer for the last layer
if self.sampler in ['sgld', 'lmc']:
grads_vars = self.gd_opt.compute_gradients(self.bayesian_loss)
grads_vars_sgld = []
for g, v in grads_vars:
if g is not None:
s = list(v.name)
s[v.name.rindex(':')] = '_'
# Adding Gaussian noise to the gradient
gaussian_noise = (np.sqrt(2. / self.step_size) *
tf.random_normal(tf.shape(g)))
g_sgld = g + gaussian_noise
tf.summary.histogram(''.join(s) + '/grad_hist_mcmc', g)
tf.summary.histogram(
''.join(s) + '/gaussian_noise_hist_mcmc',
gaussian_noise)
tf.summary.histogram(
''.join(s) + '/grad_total_hist_mcmc', g_sgld)
grads_vars_sgld.append((g_sgld, v))
self.train_op = self.gd_opt.apply_gradients(grads_vars_sgld)
# SGD optimizer for the last layer
if self.sampler == 'sgd':
grads_vars_sgd = self.gd_opt.compute_gradients(self.loss)
self.train_op = self.gd_opt.apply_gradients(grads_vars_sgd)
for g, v in grads_vars_sgd:
if g is not None:
s = list(v.name)
s[v.name.rindex(':')] = '_'
tf.summary.histogram(''.join(s) + '/grad_hist_sgd', g)
# Merge all the summaries and write them out
self.all_summaries = tf.summary.merge_all()
location = os.path.join(self.working_dir, 'logs')
self.writer = tf.summary.FileWriter(location, graph=self.g)
saver_network = tf.train.Saver(var_list=self.ll_vars)
print('loading the network ...')
# Restores from checkpoint
saver_network.restore(self.sess, self.model_dir)
print('Graph successfully loaded.')
def compute_regularizer(self, onehot_labels, predictions):
"""Computes a regularizer, maybe using `predictions` and `onehot_labels`."""
del onehot_labels
del predictions
return tf.reduce_sum(
tf.get_collection(tf.GraphKeys.REGULARIZATION_LOSSES))
def build_graph(self):
"""Builds the neural network graph."""
# define graph
self.g = tf.Graph()
with self.g.as_default():
# create and store a new session for the graph
self.sess = tf.Session()
# define placeholders
self.x = tf.placeholder(shape=[None, self.dim_input],
dtype=tf.float32)
self.y = tf.placeholder(shape=[None, self.num_classes],
dtype=tf.float32)
# define simple model
with tf.variable_scope('last_layer'):
self.z = tf.layers.dense(inputs=self.x, units=self.num_classes)
self.loss = tf.reduce_mean(
tf.nn.softmax_cross_entropy_with_logits_v2(labels=self.y,
logits=self.z))
self.output_probs = tf.nn.softmax(self.z)
# Variables of the last layer
self.ll_vars = tf.get_collection(tf.GraphKeys.TRAINABLE_VARIABLES)
self.ll_vars_concat = tf.concat(
[self.ll_vars[0],
tf.expand_dims(self.ll_vars[1], axis=0)], 0)
# Summary
_variable_summaries(self.ll_vars_concat)
# add regularization that acts as a unit Gaussian prior on the last layer
regularizer = tf.contrib.layers.l2_regularizer(1.0)
# regularization
prior = tf.contrib.layers.apply_regularization(
regularizer, self.ll_vars)
self.bayesian_loss = self.n * self.loss + prior
# saving the weights of last layer when running SGLD/SGD/MCMC algorithm
self.saver = tf.train.Saver(var_list=self.ll_vars,
max_to_keep=self.num_samples)
# SGLD optimizer for the last layer
if self.sampler in ['sgld', 'lmc']:
step = self.step_size / self.n
gd_opt = tf.train.GradientDescentOptimizer(step)
grads_vars = gd_opt.compute_gradients(self.bayesian_loss)
grads_vars_sgld = []
for g, v in grads_vars:
if g is not None:
s = list(v.name)
s[v.name.rindex(':')] = '_'
# Adding Gaussian noise to the gradient
gaussian_noise = (np.sqrt(2. / step) *
tf.random_normal(tf.shape(g)))
g_sgld = g + gaussian_noise
tf.summary.histogram(''.join(s) + '/grad_hist_mcmc',
g / self.n)
tf.summary.histogram(
''.join(s) + '/gaussian_noise_hist_mcmc',
gaussian_noise / self.n)
tf.summary.histogram(
''.join(s) + '/grad_total_hist_mcmc',
g_sgld / self.n)
grads_vars_sgld.append((g_sgld, v))
self.train_op = gd_opt.apply_gradients(grads_vars_sgld)
# SGD optimizer for the last layer
if self.sampler == 'sgd':
gd_opt = tf.train.GradientDescentOptimizer(self.step_size)
grads_vars_sgd = gd_opt.compute_gradients(self.loss)
self.train_op = gd_opt.apply_gradients(grads_vars_sgd)
for g, v in grads_vars_sgd:
if g is not None:
s = list(v.name)
s[v.name.rindex(':')] = '_'
tf.summary.histogram(''.join(s) + '/grad_hist_sgd', g)
# Merge all the summaries and write them out
self.all_summaries = tf.summary.merge_all()
location = os.path.join(self.working_dir, 'logs')
self.writer = tf.summary.FileWriter(location, graph=self.g)
saver_network = tf.train.Saver(var_list=self.ll_vars)
print('loading the network ...')
# Restores from checkpoint
# self.sess.run(tf.global_variables_initializer())
saver_network.restore(self.sess, self.model_dir)
print('Graph successfully loaded.')
def compute_regularizer(self):
"""Computes a regularizer, independent of the data."""
return tf.reduce_sum(
tf.get_collection(tf.GraphKeys.REGULARIZATION_LOSSES))
def get_train_op(loss,
learning_rate=0.001,
lr_decay_steps=10000,
lr_decay_rate=0.98,
gradient_clip_norm=3.0,
use_tpu=True,
variables=None):
"""Get training operation with gradient clipping and learning rate decay.
Distilled from tf.contrib.layers.optimize_loss().
Args:
loss: Scalar tensor of the loss function.
learning_rate: Scalar initial learning rate.
lr_decay_steps: Exponential decay timescale.
lr_decay_rate: Exponential decay magnitude.
gradient_clip_norm: Global norm by which to scale gradients.
use_tpu: Use tpu for training.
variables: List of variables to optimize. tf.trainable_variables() if None.
Returns:
train_op: Operation that runs one iteration of training.
"""
global_step = tf.train.get_or_create_global_step()
with tf.variable_scope('training', values=[loss, global_step]):
# Make sure update ops run before computing loss.
update_ops = list(set(tf.get_collection(tf.GraphKeys.UPDATE_OPS)))
with tf.control_dependencies(update_ops):
loss = tf.identity(loss)
# Learning rate variable, with decay.
learning_rate_decay_fn = functools.partial(tf.train.exponential_decay,
decay_steps=lr_decay_steps,
decay_rate=lr_decay_rate,
staircase=True)
lr = tf.get_variable(
'learning_rate', [],
trainable=False,
initializer=tf.constant_initializer(learning_rate))
lr = learning_rate_decay_fn(lr, global_step)
# Optimizer.
opt = tf.train.AdamOptimizer(lr)
if use_tpu:
opt = tf.tpu.CrossShardOptimizer(opt)
# All trainable variables, if specific variables are not specified.
if variables is None:
variables = tf.trainable_variables()
# Compute gradients.
gradients = opt.compute_gradients(loss,
variables,
colocate_gradients_with_ops=False)
# Optionally clip gradients by global norm.
if isinstance(gradient_clip_norm, float):
gradients = _clip_gradients_by_norm(gradients, gradient_clip_norm)
# Create gradient updates.
grad_updates = opt.apply_gradients(gradients,
global_step=global_step,
name='train')
# Ensure the train_op computes grad_updates.
with tf.control_dependencies([grad_updates]):
train_op = tf.identity(loss)
return train_op