Merge branch 'master' into patch-13

research/fivo/fivo.py

+# Copyright 2017 The TensorFlow Authors All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+
+"""A script to run training for sequential latent variable models.
+"""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import tensorflow as tf
+
+import runners
+
+# Shared flags.
+tf.app.flags.DEFINE_string("mode", "train",
+                           "The mode of the binary. Must be 'train' or 'test'.")
+tf.app.flags.DEFINE_string("model", "vrnn",
+                           "Model choice. Currently only 'vrnn' is supported.")
+tf.app.flags.DEFINE_integer("latent_size", 64,
+                            "The size of the latent state of the model.")
+tf.app.flags.DEFINE_string("dataset_type", "pianoroll",
+                           "The type of dataset, either 'pianoroll' or 'speech'.")
+tf.app.flags.DEFINE_string("dataset_path", "",
+                           "Path to load the dataset from.")
+tf.app.flags.DEFINE_integer("data_dimension", None,
+                            "The dimension of each vector in the data sequence. "
+                            "Defaults to 88 for pianoroll datasets and 200 for speech "
+                            "datasets. Should not need to be changed except for "
+                            "testing.")
+tf.app.flags.DEFINE_integer("batch_size", 4,
+                            "Batch size.")
+tf.app.flags.DEFINE_integer("num_samples", 4,
+                           "The number of samples (or particles) for multisample "
+                           "algorithms.")
+tf.app.flags.DEFINE_string("logdir", "/tmp/smc_vi",
+                           "The directory to keep checkpoints and summaries in.")
+tf.app.flags.DEFINE_integer("random_seed", None,
+                            "A random seed for seeding the TensorFlow graph.")
+
+# Training flags.
+tf.app.flags.DEFINE_string("bound", "fivo",
+                           "The bound to optimize. Can be 'elbo', 'iwae', or 'fivo'.")
+tf.app.flags.DEFINE_boolean("normalize_by_seq_len", True,
+                            "If true, normalize the loss by the number of timesteps "
+                            "per sequence.")
+tf.app.flags.DEFINE_float("learning_rate", 0.0002,
+                          "The learning rate for ADAM.")
+tf.app.flags.DEFINE_integer("max_steps", int(1e9),
+                            "The number of gradient update steps to train for.")
+tf.app.flags.DEFINE_integer("summarize_every", 50,
+                            "The number of steps between summaries.")
+
+# Distributed training flags.
+tf.app.flags.DEFINE_string("master", "",
+                           "The BNS name of the TensorFlow master to use.")
+tf.app.flags.DEFINE_integer("task", 0,
+                            "Task id of the replica running the training.")
+tf.app.flags.DEFINE_integer("ps_tasks", 0,
+                            "Number of tasks in the ps job. If 0 no ps job is used.")
+tf.app.flags.DEFINE_boolean("stagger_workers", True,
+                            "If true, bring one worker online every 1000 steps.")
+
+# Evaluation flags.
+tf.app.flags.DEFINE_string("split", "train",
+                           "Split to evaluate the model on. Can be 'train', 'valid', or 'test'.")
+
+FLAGS = tf.app.flags.FLAGS
+
+PIANOROLL_DEFAULT_DATA_DIMENSION = 88
+SPEECH_DEFAULT_DATA_DIMENSION = 200
+
+
+def main(unused_argv):
+  tf.logging.set_verbosity(tf.logging.INFO)
+  if FLAGS.data_dimension is None:
+    if FLAGS.dataset_type == "pianoroll":
+      FLAGS.data_dimension = PIANOROLL_DEFAULT_DATA_DIMENSION
+    elif FLAGS.dataset_type == "speech":
+      FLAGS.data_dimension = SPEECH_DEFAULT_DATA_DIMENSION
+  if FLAGS.mode == "train":
+    runners.run_train(FLAGS)
+  elif FLAGS.mode == "eval":
+    runners.run_eval(FLAGS)
+
+if __name__ == "__main__":
+  tf.app.run()

research/fivo/models/vrnn.py

+# Copyright 2017 The TensorFlow Authors All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+
+"""VRNN classes."""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import sonnet as snt
+import tensorflow as tf
+
+
+class VRNNCell(snt.AbstractModule):
+  """Implementation of a Variational Recurrent Neural Network (VRNN).
+
+  Introduced in "A Recurrent Latent Variable Model for Sequential data"
+  by Chung et al. https://arxiv.org/pdf/1506.02216.pdf.
+
+  The VRNN is a sequence model similar to an RNN that uses stochastic latent
+  variables to improve its representational power. It can be thought of as a
+  sequential analogue to the variational auto-encoder (VAE).
+
+  The VRNN has a deterministic RNN as its backbone, represented by the
+  sequence of RNN hidden states h_t. At each timestep, the RNN hidden state h_t
+  is conditioned on the previous sequence element, x_{t-1}, as well as the
+  latent state from the previous timestep, z_{t-1}.
+
+  In this implementation of the VRNN the latent state z_t is Gaussian. The
+  model's prior over z_t is distributed as Normal(mu_t, diag(sigma_t^2)) where
+  mu_t and sigma_t are the mean and standard deviation output from a fully
+  connected network that accepts the rnn hidden state h_t as input.
+
+  The approximate posterior (also known as q or the encoder in the VAE
+  framework) is similar to the prior except that it is conditioned on the
+  current target, x_t, as well as h_t via a fully connected network.
+
+  This implementation uses the 'res_q' parameterization of the approximate
+  posterior, meaning that instead of directly predicting the mean of z_t, the
+  approximate posterior predicts the 'residual' from the prior's mean. This is
+  explored more in section 3.3 of https://arxiv.org/pdf/1605.07571.pdf.
+
+  During training, the latent state z_t is sampled from the approximate
+  posterior and the reparameterization trick is used to provide low-variance
+  gradients.
+
+  The generative distribution p(x_t|z_t, h_t) is conditioned on the latent state
+  z_t as well as the current RNN hidden state h_t via a fully connected network.
+
+  To increase the modeling power of the VRNN, two additional networks are
+  used to extract features from the data and the latent state. Those networks
+  are called data_feat_extractor and latent_feat_extractor respectively.
+
+  There are a few differences between this exposition and the paper.
+  First, the indexing scheme for h_t is different than the paper's -- what the
+  paper calls h_t we call h_{t+1}. This is the same notation used by Fraccaro
+  et al. to describe the VRNN in the paper linked above. Also, the VRNN paper
+  uses VAE terminology to refer to the different internal networks, so it
+  refers to the approximate posterior as the encoder and the generative
+  distribution as the decoder. This implementation also renamed the functions
+  phi_x and phi_z in the paper to data_feat_extractor and latent_feat_extractor.
+  """
+
+  def __init__(self,
+               rnn_cell,
+               data_feat_extractor,
+               latent_feat_extractor,
+               prior,
+               approx_posterior,
+               generative,
+               random_seed=None,
+               name="vrnn"):
+    """Creates a VRNN cell.
+
+    Args:
+      rnn_cell: A subclass of tf.nn.rnn_cell.RNNCell that will form the
+        deterministic backbone of the VRNN. The inputs to the RNN will be the
+        encoded latent state of the previous timestep with shape
+        [batch_size, encoded_latent_size] as well as the encoded input of the
+        current timestep, a Tensor of shape [batch_size, encoded_data_size].
+      data_feat_extractor: A callable that accepts a batch of data x_t and
+        'encodes' it, e.g. runs it through a fully connected network. Must
+        accept as argument the inputs x_t, a Tensor of the shape
+        [batch_size, data_size] and return a Tensor of shape
+        [batch_size, encoded_data_size]. This callable will be called multiple
+        times in the VRNN cell so if scoping is not handled correctly then
+        multiple copies of the variables in this network could be made. It is
+        recommended to use a snt.nets.MLP module, which takes care of this for
+        you.
+      latent_feat_extractor: A callable that accepts a latent state z_t and
+        'encodes' it, e.g. runs it through a fully connected network. Must
+        accept as argument a Tensor of shape [batch_size, latent_size] and
+        return a Tensor of shape [batch_size, encoded_latent_size].
+        This callable must also have the property 'output_size' defined,
+        returning encoded_latent_size.
+      prior: A callable that implements the prior p(z_t|h_t). Must accept as
+        argument the previous RNN hidden state and return a
+        tf.contrib.distributions.Normal distribution conditioned on the input.
+      approx_posterior: A callable that implements the approximate posterior
+        q(z_t|h_t,x_t). Must accept as arguments the encoded target of the
+        current timestep and the previous RNN hidden state. Must return
+        a tf.contrib.distributions.Normal distribution conditioned on the
+        inputs.
+      generative: A callable that implements the generative distribution
+        p(x_t|z_t, h_t). Must accept as arguments the encoded latent state
+        and the RNN hidden state and return a subclass of
+        tf.contrib.distributions.Distribution that can be used to evaluate
+        the logprob of the targets.
+      random_seed: The seed for the random ops. Used mainly for testing.
+      name: The name of this VRNN.
+    """
+    super(VRNNCell, self).__init__(name=name)
+    self.rnn_cell = rnn_cell
+    self.data_feat_extractor = data_feat_extractor
+    self.latent_feat_extractor = latent_feat_extractor
+    self.prior = prior
+    self.approx_posterior = approx_posterior
+    self.generative = generative
+    self.random_seed = random_seed
+    self.encoded_z_size = latent_feat_extractor.output_size
+    self.state_size = (self.rnn_cell.state_size, self.encoded_z_size)
+
+  def zero_state(self, batch_size, dtype):
+    """The initial state of the VRNN.
+
+    Contains the initial state of the RNN as well as a vector of zeros
+    corresponding to z_0.
+    Args:
+      batch_size: The batch size.
+      dtype: The data type of the VRNN.
+    Returns:
+      zero_state: The initial state of the VRNN.
+    """
+    return (self.rnn_cell.zero_state(batch_size, dtype),
+            tf.zeros([batch_size, self.encoded_z_size], dtype=dtype))
+
+  def _build(self, observations, state, mask):
+    """Computes one timestep of the VRNN.
+
+    Args:
+      observations: The observations at the current timestep, a tuple
+        containing the model inputs and targets as Tensors of shape
+        [batch_size, data_size].
+      state: The current state of the VRNN
+      mask: Tensor of shape [batch_size], 1.0 if the current timestep is active
+        active, 0.0 if it is not active.
+
+    Returns:
+      log_q_z: The logprob of the latent state according to the approximate
+        posterior.
+      log_p_z: The logprob of the latent state according to the prior.
+      log_p_x_given_z: The conditional log-likelihood, i.e. logprob of the
+        observation according to the generative distribution.
+      kl: The analytic kl divergence from q(z) to p(z).
+      state: The new state of the VRNN.
+    """
+    inputs, targets = observations
+    rnn_state, prev_latent_encoded = state
+    # Encode the data.
+    inputs_encoded = self.data_feat_extractor(inputs)
+    targets_encoded = self.data_feat_extractor(targets)
+    # Run the RNN cell.
+    rnn_inputs = tf.concat([inputs_encoded, prev_latent_encoded], axis=1)
+    rnn_out, new_rnn_state = self.rnn_cell(rnn_inputs, rnn_state)
+    # Create the prior and approximate posterior distributions.
+    latent_dist_prior = self.prior(rnn_out)
+    latent_dist_q = self.approx_posterior(rnn_out, targets_encoded,
+                                          prior_mu=latent_dist_prior.loc)
+    # Sample the new latent state z and encode it.
+    latent_state = latent_dist_q.sample(seed=self.random_seed)
+    latent_encoded = self.latent_feat_extractor(latent_state)
+    # Calculate probabilities of the latent state according to the prior p
+    # and approximate posterior q.
+    log_q_z = tf.reduce_sum(latent_dist_q.log_prob(latent_state), axis=-1)
+    log_p_z = tf.reduce_sum(latent_dist_prior.log_prob(latent_state), axis=-1)
+    analytic_kl = tf.reduce_sum(
+        tf.contrib.distributions.kl_divergence(
+            latent_dist_q, latent_dist_prior),
+        axis=-1)
+    # Create the generative dist. and calculate the logprob of the targets.
+    generative_dist = self.generative(latent_encoded, rnn_out)
+    log_p_x_given_z = tf.reduce_sum(generative_dist.log_prob(targets), axis=-1)
+    return (log_q_z, log_p_z, log_p_x_given_z, analytic_kl,
+            (new_rnn_state, latent_encoded))
+
+_DEFAULT_INITIALIZERS = {"w": tf.contrib.layers.xavier_initializer(),
+                         "b": tf.zeros_initializer()}
+
+
+def create_vrnn(
+    data_size,
+    latent_size,
+    generative_class,
+    rnn_hidden_size=None,
+    fcnet_hidden_sizes=None,
+    encoded_data_size=None,
+    encoded_latent_size=None,
+    sigma_min=0.0,
+    raw_sigma_bias=0.25,
+    generative_bias_init=0.0,
+    initializers=None,
+    random_seed=None):
+  """A factory method for creating VRNN cells.
+
+  Args:
+    data_size: The dimension of the vectors that make up the data sequences.
+    latent_size: The size of the stochastic latent state of the VRNN.
+    generative_class: The class of the generative distribution. Can be either
+      ConditionalNormalDistribution or ConditionalBernoulliDistribution.
+    rnn_hidden_size: The hidden state dimension of the RNN that forms the
+      deterministic part of this VRNN. If None, then it defaults
+      to latent_size.
+    fcnet_hidden_sizes: A list of python integers, the size of the hidden
+      layers of the fully connected networks that parameterize the conditional
+      distributions of the VRNN. If None, then it defaults to one hidden
+      layer of size latent_size.
+    encoded_data_size: The size of the output of the data encoding network. If
+      None, defaults to latent_size.
+    encoded_latent_size: The size of the output of the latent state encoding
+      network. If None, defaults to latent_size.
+    sigma_min: The minimum value that the standard deviation of the
+      distribution over the latent state can take.
+    raw_sigma_bias: A scalar that is added to the raw standard deviation
+      output from the neural networks that parameterize the prior and
+      approximate posterior. Useful for preventing standard deviations close
+      to zero.
+    generative_bias_init: A bias to added to the raw output of the fully
+      connected network that parameterizes the generative distribution. Useful
+      for initalizing the mean of the distribution to a sensible starting point
+      such as the mean of the training data. Only used with Bernoulli generative
+      distributions.
+    initializers: The variable intitializers to use for the fully connected
+      networks and RNN cell. Must be a dictionary mapping the keys 'w' and 'b'
+      to the initializers for the weights and biases. Defaults to xavier for
+      the weights and zeros for the biases when initializers is None.
+    random_seed: A random seed for the VRNN resampling operations.
+  Returns:
+    model: A VRNNCell object.
+  """
+  if rnn_hidden_size is None:
+    rnn_hidden_size = latent_size
+  if fcnet_hidden_sizes is None:
+    fcnet_hidden_sizes = [latent_size]
+  if encoded_data_size is None:
+    encoded_data_size = latent_size
+  if encoded_latent_size is None:
+    encoded_latent_size = latent_size
+  if initializers is None:
+    initializers = _DEFAULT_INITIALIZERS
+  data_feat_extractor = snt.nets.MLP(
+      output_sizes=fcnet_hidden_sizes + [encoded_data_size],
+      initializers=initializers,
+      name="data_feat_extractor")
+  latent_feat_extractor = snt.nets.MLP(
+      output_sizes=fcnet_hidden_sizes + [encoded_latent_size],
+      initializers=initializers,
+      name="latent_feat_extractor")
+  prior = ConditionalNormalDistribution(
+      size=latent_size,
+      hidden_layer_sizes=fcnet_hidden_sizes,
+      sigma_min=sigma_min,
+      raw_sigma_bias=raw_sigma_bias,
+      initializers=initializers,
+      name="prior")
+  approx_posterior = NormalApproximatePosterior(
+      size=latent_size,
+      hidden_layer_sizes=fcnet_hidden_sizes,
+      sigma_min=sigma_min,
+      raw_sigma_bias=raw_sigma_bias,
+      initializers=initializers,
+      name="approximate_posterior")
+  if generative_class == ConditionalBernoulliDistribution:
+    generative = ConditionalBernoulliDistribution(
+        size=data_size,
+        hidden_layer_sizes=fcnet_hidden_sizes,
+        initializers=initializers,
+        bias_init=generative_bias_init,
+        name="generative")
+  else:
+    generative = ConditionalNormalDistribution(
+        size=data_size,
+        hidden_layer_sizes=fcnet_hidden_sizes,
+        initializers=initializers,
+        name="generative")
+  rnn_cell = tf.nn.rnn_cell.LSTMCell(rnn_hidden_size,
+                                     initializer=initializers["w"])
+  return VRNNCell(rnn_cell, data_feat_extractor, latent_feat_extractor,
+                  prior, approx_posterior, generative, random_seed=random_seed)
+
+
+class ConditionalNormalDistribution(object):
+  """A Normal distribution conditioned on Tensor inputs via a fc network."""
+
+  def __init__(self, size, hidden_layer_sizes, sigma_min=0.0,
+               raw_sigma_bias=0.25, hidden_activation_fn=tf.nn.relu,
+               initializers=None, name="conditional_normal_distribution"):
+    """Creates a conditional Normal distribution.
+
+    Args:
+      size: The dimension of the random variable.
+      hidden_layer_sizes: The sizes of the hidden layers of the fully connected
+        network used to condition the distribution on the inputs.
+      sigma_min: The minimum standard deviation allowed, a scalar.
+      raw_sigma_bias: A scalar that is added to the raw standard deviation
+        output from the fully connected network. Set to 0.25 by default to
+        prevent standard deviations close to 0.
+      hidden_activation_fn: The activation function to use on the hidden layers
+        of the fully connected network.
+      initializers: The variable intitializers to use for the fully connected
+        network. The network is implemented using snt.nets.MLP so it must
+        be a dictionary mapping the keys 'w' and 'b' to the initializers for
+        the weights and biases. Defaults to xavier for the weights and zeros
+        for the biases when initializers is None.
+      name: The name of this distribution, used for sonnet scoping.
+    """
+    self.sigma_min = sigma_min
+    self.raw_sigma_bias = raw_sigma_bias
+    self.name = name
+    if initializers is None:
+      initializers = _DEFAULT_INITIALIZERS
+    self.fcnet = snt.nets.MLP(
+        output_sizes=hidden_layer_sizes + [2*size],
+        activation=hidden_activation_fn,
+        initializers=initializers,
+        activate_final=False,
+        use_bias=True,
+        name=name + "_fcnet")
+
+  def condition(self, tensor_list, **unused_kwargs):
+    """Computes the parameters of a normal distribution based on the inputs."""
+    inputs = tf.concat(tensor_list, axis=1)
+    outs = self.fcnet(inputs)
+    mu, sigma = tf.split(outs, 2, axis=1)
+    sigma = tf.maximum(tf.nn.softplus(sigma + self.raw_sigma_bias),
+                       self.sigma_min)
+    return mu, sigma
+
+  def __call__(self, *args, **kwargs):
+    """Creates a normal distribution conditioned on the inputs."""
+    mu, sigma = self.condition(args, **kwargs)
+    return tf.contrib.distributions.Normal(loc=mu, scale=sigma)
+
+
+class ConditionalBernoulliDistribution(object):
+  """A Bernoulli distribution conditioned on Tensor inputs via a fc net."""
+
+  def __init__(self, size, hidden_layer_sizes, hidden_activation_fn=tf.nn.relu,
+               initializers=None, bias_init=0.0,
+               name="conditional_bernoulli_distribution"):
+    """Creates a conditional Bernoulli distribution.
+
+    Args:
+      size: The dimension of the random variable.
+      hidden_layer_sizes: The sizes of the hidden layers of the fully connected
+        network used to condition the distribution on the inputs.
+      hidden_activation_fn: The activation function to use on the hidden layers
+        of the fully connected network.
+      initializers: The variable intiializers to use for the fully connected
+        network. The network is implemented using snt.nets.MLP so it must
+        be a dictionary mapping the keys 'w' and 'b' to the initializers for
+        the weights and biases. Defaults to xavier for the weights and zeros
+        for the biases when initializers is None.
+      bias_init: A scalar or vector Tensor that is added to the output of the
+        fully-connected network that parameterizes the mean of this
+        distribution.
+      name: The name of this distribution, used for sonnet scoping.
+    """
+    self.bias_init = bias_init
+    if initializers is None:
+      initializers = _DEFAULT_INITIALIZERS
+    self.fcnet = snt.nets.MLP(
+        output_sizes=hidden_layer_sizes + [size],
+        activation=hidden_activation_fn,
+        initializers=initializers,
+        activate_final=False,
+        use_bias=True,
+        name=name + "_fcnet")
+
+  def condition(self, tensor_list):
+    """Computes the p parameter of the Bernoulli distribution."""
+    inputs = tf.concat(tensor_list, axis=1)
+    return self.fcnet(inputs) + self.bias_init
+
+  def __call__(self, *args):
+    p = self.condition(args)
+    return tf.contrib.distributions.Bernoulli(logits=p)
+
+
+class NormalApproximatePosterior(ConditionalNormalDistribution):
+  """A Normally-distributed approx. posterior with res_q parameterization."""
+
+  def condition(self, tensor_list, prior_mu):
+    """Generates the mean and variance of the normal distribution.
+
+    Args:
+      tensor_list: The list of Tensors to condition on. Will be concatenated and
+        fed through a fully connected network.
+      prior_mu: The mean of the prior distribution associated with this
+        approximate posterior. Will be added to the mean produced by
+        this approximate posterior, in res_q fashion.
+    Returns:
+      mu: The mean of the approximate posterior.
+      sigma: The standard deviation of the approximate posterior.
+    """
+    mu, sigma = super(NormalApproximatePosterior, self).condition(tensor_list)
+    return mu + prior_mu, sigma

research/fivo/nested_utils.py

+# Copyright 2017 The TensorFlow Authors All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+
+"""A set of utils for dealing with nested lists and tuples of Tensors."""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import tensorflow as tf
+from tensorflow.python.util import nest
+
+def map_nested(map_fn, nested):
+  """Executes map_fn on every element in a (potentially) nested structure.
+
+  Args:
+    map_fn: A callable to execute on each element in 'nested'.
+    nested: A potentially nested combination of sequence objects. Sequence
+      objects include tuples, lists, namedtuples, and all subclasses of
+      collections.Sequence except strings. See nest.is_sequence for details.
+      For example [1, ('hello', 4.3)] is a nested structure containing elements
+      1, 'hello', and 4.3.
+  Returns:
+    out_structure: A potentially nested combination of sequence objects with the
+      same structure as the 'nested' input argument. out_structure
+      contains the result of applying map_fn to each element in 'nested'. For
+      example map_nested(lambda x: x+1, [1, (3, 4.3)]) returns [2, (4, 5.3)].
+  """
+  out = map(map_fn, nest.flatten(nested))
+  return nest.pack_sequence_as(nested, out)
+
+
+def tile_tensors(tensors, multiples):
+  """Tiles a set of Tensors.
+
+  Args:
+    tensors: A potentially nested tuple or list of Tensors with rank
+      greater than or equal to the length of 'multiples'. The Tensors do not
+      need to have the same rank, but their rank must not be dynamic.
+    multiples: A python list of ints indicating how to tile each Tensor
+      in 'tensors'. Similar to the 'multiples' argument to tf.tile.
+  Returns:
+    tiled_tensors: A potentially nested tuple or list of Tensors with the same
+      structure as the 'tensors' input argument. Contains the result of
+      applying tf.tile to each Tensor in 'tensors'. When the rank of a Tensor
+      in 'tensors' is greater than the length of multiples, multiples is padded
+      at the end with 1s. For example when tiling a 4-dimensional Tensor with
+      multiples [3, 4], multiples would be padded to [3, 4, 1, 1] before tiling.
+  """
+  def tile_fn(x):
+    return tf.tile(x, multiples + [1]*(x.shape.ndims - len(multiples)))
+
+  return map_nested(tile_fn, tensors)
+
+
+def gather_tensors(tensors, indices):
+  """Performs a tf.gather operation on a set of Tensors.
+
+  Args:
+    tensors: A potentially nested tuple or list of Tensors.
+    indices: The indices to use for the gather operation.
+  Returns:
+    gathered_tensors: A potentially nested tuple or list of Tensors with the
+      same structure as the 'tensors' input argument. Contains the result of
+      applying tf.gather(x, indices) on each element x in 'tensors'.
+  """
+  return map_nested(lambda x: tf.gather(x, indices), tensors)
+
+
+def tas_for_tensors(tensors, length):
+  """Unstacks a set of Tensors into TensorArrays.
+
+  Args:
+    tensors: A potentially nested tuple or list of Tensors with length in the
+      first dimension greater than or equal to the 'length' input argument.
+    length: The desired length of the TensorArrays.
+  Returns:
+    tensorarrays: A potentially nested tuple or list of TensorArrays with the
+      same structure as 'tensors'. Contains the result of unstacking each Tensor
+      in 'tensors'.
+  """
+  def map_fn(x):
+    ta = tf.TensorArray(x.dtype, length, name=x.name.split(':')[0] + '_ta')
+    return ta.unstack(x[:length, :])
+  return map_nested(map_fn, tensors)
+
+
+def read_tas(tas, index):
+  """Performs a read operation on a set of TensorArrays.
+
+  Args:
+    tas: A potentially nested tuple or list of TensorArrays with length greater
+      than 'index'.
+    index: The location to read from.
+  Returns:
+    read_tensors: A potentially nested tuple or list of Tensors with the same
+      structure as the 'tas' input argument. Contains the result of
+      performing a read operation at 'index' on each TensorArray in 'tas'.
+  """
+  return map_nested(lambda ta: ta.read(index), tas)

research/fivo/runners.py

+# Copyright 2017 The TensorFlow Authors All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+
+"""High-level code for creating and running FIVO-related Tensorflow graphs.
+"""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+
+import os
+import time
+
+import numpy as np
+import tensorflow as tf
+
+import bounds
+from data import datasets
+from models import vrnn
+
+
+def create_dataset_and_model(config, split, shuffle, repeat):
+  """Creates the dataset and model for a given config.
+
+  Args:
+    config: A configuration object with config values accessible as properties.
+      Most likely a FLAGS object. This function expects the properties
+      batch_size, dataset_path, dataset_type, and latent_size to be defined.
+    split: The dataset split to load.
+    shuffle: If true, shuffle the dataset randomly.
+    repeat: If true, repeat the dataset endlessly.
+  Returns:
+    inputs: A batch of input sequences represented as a dense Tensor of shape
+      [time, batch_size, data_dimension].
+    targets: A batch of target sequences represented as a dense Tensor of
+      shape [time, batch_size, data_dimension].
+    lens: An int Tensor of shape [batch_size] representing the lengths of each
+      sequence in the batch.
+    model: A vrnn.VRNNCell model object.
+  """
+  if config.dataset_type == "pianoroll":
+    inputs, targets, lengths, mean = datasets.create_pianoroll_dataset(
+        config.dataset_path, split, config.batch_size, shuffle=shuffle,
+        repeat=repeat)
+    # Convert the mean of the training set to logit space so it can be used to
+    # initialize the bias of the generative distribution.
+    generative_bias_init = -tf.log(
+        1. / tf.clip_by_value(mean, 0.0001, 0.9999) - 1)
+    generative_distribution_class = vrnn.ConditionalBernoulliDistribution
+  elif config.dataset_type == "speech":
+    inputs, targets, lengths = datasets.create_speech_dataset(
+        config.dataset_path, config.batch_size,
+        samples_per_timestep=config.data_dimension, prefetch_buffer_size=1,
+        shuffle=False, repeat=False)
+    generative_bias_init = None
+    generative_distribution_class = vrnn.ConditionalNormalDistribution
+  model = vrnn.create_vrnn(inputs.get_shape().as_list()[2],
+                           config.latent_size,
+                           generative_distribution_class,
+                           generative_bias_init=generative_bias_init,
+                           raw_sigma_bias=0.5)
+  return inputs, targets, lengths, model
+
+
+def restore_checkpoint_if_exists(saver, sess, logdir):
+  """Looks for a checkpoint and restores the session from it if found.
+
+  Args:
+    saver: A tf.train.Saver for restoring the session.
+    sess: A TensorFlow session.
+    logdir: The directory to look for checkpoints in.
+  Returns:
+    True if a checkpoint was found and restored, False otherwise.
+  """
+  checkpoint = tf.train.get_checkpoint_state(logdir)
+  if checkpoint:
+    checkpoint_name = os.path.basename(checkpoint.model_checkpoint_path)
+    full_checkpoint_path = os.path.join(logdir, checkpoint_name)
+    saver.restore(sess, full_checkpoint_path)
+    return True
+  return False
+
+
+def wait_for_checkpoint(saver, sess, logdir):
+  """Loops until the session is restored from a checkpoint in logdir.
+
+  Args:
+    saver: A tf.train.Saver for restoring the session.
+    sess: A TensorFlow session.
+    logdir: The directory to look for checkpoints in.
+  """
+  while True:
+    if restore_checkpoint_if_exists(saver, sess, logdir):
+      break
+    else:
+      tf.logging.info("Checkpoint not found in %s, sleeping for 60 seconds."
+                      % logdir)
+      time.sleep(60)
+
+
+def run_train(config):
+  """Runs training for a sequential latent variable model.
+
+  Args:
+    config: A configuration object with config values accessible as properties.
+      Most likely a FLAGS object. For a list of expected properties and their
+      meaning see the flags defined in fivo.py.
+  """
+
+  def create_logging_hook(step, bound_value):
+    """Creates a logging hook that prints the bound value periodically."""
+    bound_label = config.bound + " bound"
+    if config.normalize_by_seq_len:
+      bound_label += " per timestep"
+    else:
+      bound_label += " per sequence"
+    def summary_formatter(log_dict):
+      return "Step %d, %s: %f" % (
+          log_dict["step"], bound_label, log_dict["bound_value"])
+    logging_hook = tf.train.LoggingTensorHook(
+        {"step": step, "bound_value": bound_value},
+        every_n_iter=config.summarize_every,
+        formatter=summary_formatter)
+    return logging_hook
+
+  def create_loss():
+    """Creates the loss to be optimized.
+
+    Returns:
+      bound: A float Tensor containing the value of the bound that is
+        being optimized.
+      loss: A float Tensor that when differentiated yields the gradients
+        to apply to the model. Should be optimized via gradient descent.
+    """
+    inputs, targets, lengths, model = create_dataset_and_model(
+        config, split="train", shuffle=True, repeat=True)
+    # Compute lower bounds on the log likelihood.
+    if config.bound == "elbo":
+      ll_per_seq, _, _, _ = bounds.iwae(
+          model, (inputs, targets), lengths, num_samples=1)
+    elif config.bound == "iwae":
+      ll_per_seq, _, _, _ = bounds.iwae(
+          model, (inputs, targets), lengths, num_samples=config.num_samples)
+    elif config.bound == "fivo":
+      ll_per_seq, _, _, _, _ = bounds.fivo(
+          model, (inputs, targets), lengths, num_samples=config.num_samples,
+          resampling_criterion=bounds.ess_criterion)
+    # Compute loss scaled by number of timesteps.
+    ll_per_t = tf.reduce_mean(ll_per_seq / tf.to_float(lengths))
+    ll_per_seq = tf.reduce_mean(ll_per_seq)
+
+    tf.summary.scalar("train_ll_per_seq", ll_per_seq)
+    tf.summary.scalar("train_ll_per_t", ll_per_t)
+
+    if config.normalize_by_seq_len:
+      return ll_per_t, -ll_per_t
+    else:
+      return ll_per_seq, -ll_per_seq
+
+  def create_graph():
+    """Creates the training graph."""
+    global_step = tf.train.get_or_create_global_step()
+    bound, loss = create_loss()
+    opt = tf.train.AdamOptimizer(config.learning_rate)
+    grads = opt.compute_gradients(loss, var_list=tf.trainable_variables())
+    train_op = opt.apply_gradients(grads, global_step=global_step)
+    return bound, train_op, global_step
+
+  device = tf.train.replica_device_setter(ps_tasks=config.ps_tasks)
+  with tf.Graph().as_default():
+    if config.random_seed: tf.set_random_seed(config.random_seed)
+    with tf.device(device):
+      bound, train_op, global_step = create_graph()
+      log_hook = create_logging_hook(global_step, bound)
+      start_training = not config.stagger_workers
+      with tf.train.MonitoredTrainingSession(
+          master=config.master,
+          is_chief=config.task == 0,
+          hooks=[log_hook],
+          checkpoint_dir=config.logdir,
+          save_checkpoint_secs=120,
+          save_summaries_steps=config.summarize_every,
+          log_step_count_steps=config.summarize_every) as sess:
+        cur_step = -1
+        while True:
+          if sess.should_stop() or cur_step > config.max_steps: break
+          if config.task > 0 and not start_training:
+            cur_step = sess.run(global_step)
+            tf.logging.info("task %d not active yet, sleeping at step %d" %
+                            (config.task, cur_step))
+            time.sleep(30)
+            if cur_step >= config.task * 1000:
+              start_training = True
+          else:
+            _, cur_step = sess.run([train_op, global_step])
+
+
+def run_eval(config):
+  """Runs evaluation for a sequential latent variable model.
+
+  This method runs only one evaluation over the dataset, writes summaries to
+  disk, and then terminates. It does not loop indefinitely.
+
+  Args:
+    config: A configuration object with config values accessible as properties.
+      Most likely a FLAGS object. For a list of expected properties and their
+      meaning see the flags defined in fivo.py.
+  """
+
+  def create_graph():
+    """Creates the evaluation graph.
+
+    Returns:
+      lower_bounds: A tuple of float Tensors containing the values of the 3
+        evidence lower bounds, summed across the batch.
+      total_batch_length: The total number of timesteps in the batch, summed
+        across batch examples.
+      batch_size: The batch size.
+      global_step: The global step the checkpoint was loaded from.
+    """
+    global_step = tf.train.get_or_create_global_step()
+    inputs, targets, lengths, model = create_dataset_and_model(
+        config, split=config.split, shuffle=False, repeat=False)
+    # Compute lower bounds on the log likelihood.
+    elbo_ll_per_seq, _, _, _ = bounds.iwae(
+        model, (inputs, targets), lengths, num_samples=1)
+    iwae_ll_per_seq, _, _, _ = bounds.iwae(
+        model, (inputs, targets), lengths, num_samples=config.num_samples)
+    fivo_ll_per_seq, _, _, _, _ = bounds.fivo(
+        model, (inputs, targets), lengths, num_samples=config.num_samples,
+        resampling_criterion=bounds.ess_criterion)
+    elbo_ll = tf.reduce_sum(elbo_ll_per_seq)
+    iwae_ll = tf.reduce_sum(iwae_ll_per_seq)
+    fivo_ll = tf.reduce_sum(fivo_ll_per_seq)
+    batch_size = tf.shape(lengths)[0]
+    total_batch_length = tf.reduce_sum(lengths)
+    return ((elbo_ll, iwae_ll, fivo_ll), total_batch_length, batch_size,
+            global_step)
+
+  def average_bounds_over_dataset(lower_bounds, total_batch_length, batch_size,
+                                  sess):
+    """Computes the values of the bounds, averaged over the datset.
+
+    Args:
+      lower_bounds: Tuple of float Tensors containing the values of the bounds
+        evaluated on a single batch.
+      total_batch_length: Integer Tensor that represents the total number of
+        timesteps in the current batch.
+      batch_size: Integer Tensor containing the batch size. This can vary if the
+        requested batch_size does not evenly divide the size of the dataset.
+      sess: A TensorFlow Session object.
+    Returns:
+      ll_per_t: A length 3 numpy array of floats containing each bound's average
+        value, normalized by the total number of timesteps in the datset. Can
+        be interpreted as a lower bound on the average log likelihood per
+        timestep in the dataset.
+      ll_per_seq: A length 3 numpy array of floats containing each bound's
+        average value, normalized by the number of sequences in the dataset.
+        Can be interpreted as a lower bound on the average log likelihood per
+        sequence in the datset.
+    """
+    total_ll = np.zeros(3, dtype=np.float64)
+    total_n_elems = 0.0
+    total_length = 0.0
+    while True:
+      try:
+        outs = sess.run([lower_bounds, batch_size, total_batch_length])
+      except tf.errors.OutOfRangeError:
+        break
+      total_ll += outs[0]
+      total_n_elems += outs[1]
+      total_length += outs[2]
+    ll_per_t = total_ll / total_length
+    ll_per_seq = total_ll / total_n_elems
+    return ll_per_t, ll_per_seq
+
+  def summarize_lls(lls_per_t, lls_per_seq, summary_writer, step):
+    """Creates log-likelihood lower bound summaries and writes them to disk.
+
+    Args:
+      lls_per_t: An array of 3 python floats, contains the values of the
+        evaluated bounds normalized by the number of timesteps.
+      lls_per_seq: An array of 3 python floats, contains the values of the
+        evaluated bounds normalized by the number of sequences.
+      summary_writer: A tf.SummaryWriter.
+      step: The current global step.
+    """
+    def scalar_summary(name, value):
+      value = tf.Summary.Value(tag=name, simple_value=value)
+      return tf.Summary(value=[value])
+
+    for i, bound in enumerate(["elbo", "iwae", "fivo"]):
+      per_t_summary = scalar_summary("%s/%s_ll_per_t" % (config.split, bound),
+                                     lls_per_t[i])
+      per_seq_summary = scalar_summary("%s/%s_ll_per_seq" %
+                                       (config.split, bound),
+                                       lls_per_seq[i])
+      summary_writer.add_summary(per_t_summary, global_step=step)
+      summary_writer.add_summary(per_seq_summary, global_step=step)
+    summary_writer.flush()
+
+  with tf.Graph().as_default():
+    if config.random_seed: tf.set_random_seed(config.random_seed)
+    lower_bounds, total_batch_length, batch_size, global_step = create_graph()
+    summary_dir = config.logdir + "/" + config.split
+    summary_writer = tf.summary.FileWriter(
+        summary_dir, flush_secs=15, max_queue=100)
+    saver = tf.train.Saver()
+    with tf.train.SingularMonitoredSession() as sess:
+      wait_for_checkpoint(saver, sess, config.logdir)
+      step = sess.run(global_step)
+      tf.logging.info("Model restored from step %d, evaluating." % step)
+      ll_per_t, ll_per_seq = average_bounds_over_dataset(
+          lower_bounds, total_batch_length, batch_size, sess)
+      summarize_lls(ll_per_t, ll_per_seq, summary_writer, step)
+      tf.logging.info("%s elbo ll/t: %f, iwae ll/t: %f fivo ll/t: %f",
+                      config.split, ll_per_t[0], ll_per_t[1], ll_per_t[2])
+      tf.logging.info("%s elbo ll/seq: %f, iwae ll/seq: %f fivo ll/seq: %f",
+                      config.split, ll_per_seq[0], ll_per_seq[1], ll_per_seq[2])

research/gan/README.md

@@ -25,7 +25,8 @@ Maintainers of TFGAN:
 
 1. [Image compression (coming soon)](#compression)
 
-## MNIST {#mnist}
+## MNIST
+<a id='mnist'></a>
 
 We train a simple generator to produce [MNIST digits](http://yann.lecun.com/exdb/mnist/).
 The unconditional case maps noise to MNIST digits. The conditional case maps
@@ -36,22 +37,24 @@ network architectures are defined [here](https://github.com/tensorflow/models/tr
 We use a classifier trained on MNIST digit classification for evaluation.
 
 ### Unconditional MNIST
-![Unconditional GAN](g3doc/mnist_unconditional_gan.png "unconditional GAN")
+<img src="g3doc/mnist_unconditional_gan.png" title="Unconditional GAN" width="330" />
 
 ### Conditional MNIST
-![Conditional GAN](g3doc/mnist_conditional_gan.png "conditional GAN")
+<img src="g3doc/mnist_conditional_gan.png" title="Conditional GAN" width="330" />
 
 ### InfoGAN MNIST
-![InfoGAN](g3doc/mnist_infogan.png "InfoGAN")
+<img src="g3doc/mnist_infogan.png" title="InfoGAN" width="330" />
 
-## MNIST with GANEstimator {#mnist_estimator}
+## MNIST with GANEstimator
+<a id='mnist_estimator'></a>
 
 This setup is exactly the same as in the [unconditional MNIST example](#mnist), but
 uses the `tf.Learn` `GANEstimator`.
 
-![Unconditional GAN](g3doc/mnist_estimator_unconditional_gan.png "unconditional GAN")
+<img src="g3doc/mnist_estimator_unconditional_gan.png" title="Unconditional GAN" width="330" />
 
-## CIFAR10 {#cifar10}
+## CIFAR10
+<a id='cifar10'></a>
 
 We train a [DCGAN generator](https://arxiv.org/abs/1511.06434) to produce [CIFAR10 images](https://www.cs.toronto.edu/~kriz/cifar.html).
 The unconditional case maps noise to CIFAR10 images. The conditional case maps
@@ -61,12 +64,13 @@ network architectures are defined [here](https://github.com/tensorflow/models/tr
 We use the [Inception Score](https://arxiv.org/abs/1606.03498) to evaluate the images.
 
 ### Unconditional CIFAR10
-![Unconditional GAN](g3doc/cifar_unconditional_gan.png "unconditional GAN")
+<img src="g3doc/cifar_unconditional_gan.png" title="Unconditional GAN" width="330" />
 
 ### Conditional CIFAR10
-![Unconditional GAN](g3doc/cifar_conditional_gan.png "unconditional GAN"){width="330"}
+<img src="g3doc/cifar_conditional_gan.png" title="Conditional GAN" width="330" />
 
-## Image compression {#compression}
+## Image compression
+<a id='compression'></a>
 
 In neural image compression, we attempt to reduce an image to a smaller representation
 such that we can recreate the original image as closely as possible. See [`Full Resolution Image Compression with Recurrent Neural Networks`](https://arxiv.org/abs/1608.05148) for more details on using neural networks
@@ -93,12 +97,10 @@ Some other notes on the problem:
 ### Results
 
 #### No adversarial loss
-
-![compresson_no_adversarial](g3doc/compression_wf0.png "no adversarial loss")
+<img src="g3doc/compression_wf0.png" title="No adversarial loss" width="500" />
 
 #### Adversarial loss
-
-![compresson_no_adversarial](g3doc/compression_wf10000.png "with adversarial loss")
+<img src="g3doc/compression_wf10000.png" title="With adversarial loss" width="500" />
 
 ### Architectures
 

research/gan/cifar/util.py

@@ -18,6 +18,7 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
+from six.moves import xrange
 import tensorflow as tf
 tfgan = tf.contrib.gan
 

research/gan/cifar/util_test.py

@@ -37,26 +37,25 @@ class UtilTest(tf.test.TestCase):
         num_classes=3,
         num_images_per_class=1)
 
-  def test_get_inception_scores(self):
-    # Mock `inception_score` which is expensive.
-    with mock.patch.object(
-        util.tfgan.eval, 'inception_score') as mock_inception_score:
-      mock_inception_score.return_value = 1.0
-      util.get_inception_scores(
-          tf.placeholder(tf.float32, shape=[None, 28, 28, 3]),
-          batch_size=100,
-          num_inception_images=10)
-
-  def test_get_frechet_inception_distance(self):
-    # Mock `frechet_inception_distance` which is expensive.
-    with mock.patch.object(
-        util.tfgan.eval, 'frechet_inception_distance') as mock_fid:
-      mock_fid.return_value = 1.0
-      util.get_frechet_inception_distance(
-          tf.placeholder(tf.float32, shape=[None, 28, 28, 3]),
-          tf.placeholder(tf.float32, shape=[None, 28, 28, 3]),
-          batch_size=100,
-          num_inception_images=10)
+  # Mock `inception_score` which is expensive.
+  @mock.patch.object(util.tfgan.eval, 'inception_score', autospec=True)
+  def test_get_inception_scores(self, mock_inception_score):
+    mock_inception_score.return_value = 1.0
+    util.get_inception_scores(
+        tf.placeholder(tf.float32, shape=[None, 28, 28, 3]),
+        batch_size=100,
+        num_inception_images=10)
+
+  # Mock `frechet_inception_distance` which is expensive.
+  @mock.patch.object(util.tfgan.eval, 'frechet_inception_distance',
+                     autospec=True)
+  def test_get_frechet_inception_distance(self, mock_fid):
+    mock_fid.return_value = 1.0
+    util.get_frechet_inception_distance(
+        tf.placeholder(tf.float32, shape=[None, 28, 28, 3]),
+        tf.placeholder(tf.float32, shape=[None, 28, 28, 3]),
+        batch_size=100,
+        num_inception_images=10)
 
 
 if __name__ == '__main__':

research/gan/image_compression/data_provider.py

+# Copyright 2017 The TensorFlow Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+"""Contains code for loading and preprocessing the compression image data."""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+
+import tensorflow as tf
+
+from slim.datasets import dataset_factory as datasets
+
+slim = tf.contrib.slim
+
+
+def provide_data(split_name, batch_size, dataset_dir,
+                 dataset_name='imagenet', num_readers=1, num_threads=1,
+                 patch_size=128):
+  """Provides batches of image data for compression.
+
+  Args:
+    split_name: Either 'train' or 'validation'.
+    batch_size: The number of images in each batch.
+    dataset_dir: The directory where the data can be found. If `None`, use
+      default.
+    dataset_name: Name of the dataset.
+    num_readers: Number of dataset readers.
+    num_threads: Number of prefetching threads.
+    patch_size: Size of the path to extract from the image.
+
+  Returns:
+    images: A `Tensor` of size [batch_size, patch_size, patch_size, channels]
+  """
+  randomize = split_name == 'train'
+  dataset = datasets.get_dataset(
+      dataset_name, split_name, dataset_dir=dataset_dir)
+  provider = slim.dataset_data_provider.DatasetDataProvider(
+      dataset,
+      num_readers=num_readers,
+      common_queue_capacity=5 * batch_size,
+      common_queue_min=batch_size,
+      shuffle=randomize)
+  [image] = provider.get(['image'])
+
+  # Sample a patch of fixed size.
+  patch = tf.image.resize_image_with_crop_or_pad(image, patch_size, patch_size)
+  patch.shape.assert_is_compatible_with([patch_size, patch_size, 3])
+
+  # Preprocess the images. Make the range lie in a strictly smaller range than
+  # [-1, 1], so that network outputs aren't forced to the extreme ranges.
+  patch = (tf.to_float(patch) - 128.0) / 142.0
+
+  if randomize:
+    image_batch = tf.train.shuffle_batch(
+        [patch],
+        batch_size=batch_size,
+        num_threads=num_threads,
+        capacity=5 * batch_size,
+        min_after_dequeue=batch_size)
+  else:
+    image_batch = tf.train.batch(
+        [patch],
+        batch_size=batch_size,
+        num_threads=1,  # no threads so it's deterministic
+        capacity=5 * batch_size)
+
+  return image_batch
+
+
+def float_image_to_uint8(image):
+  """Convert float image in ~[-0.9, 0.9) to [0, 255] uint8.
+
+  Args:
+    image: An image tensor. Values should be in [-0.9, 0.9).
+
+  Returns:
+    Input image cast to uint8 and with integer values in [0, 255].
+  """
+  image = (image * 142.0) + 128.0
+  return tf.cast(image, tf.uint8)

research/gan/image_compression/data_provider_test.py

+# Copyright 2017 The TensorFlow Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+"""Tests for data_provider."""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import os
+
+import numpy as np
+
+import tensorflow as tf
+
+import data_provider
+
+
+class DataProviderTest(tf.test.TestCase):
+
+  def _test_data_provider_helper(self, split_name):
+    dataset_dir = os.path.join(
+        tf.flags.FLAGS.test_srcdir,
+        'google3/third_party/tensorflow_models/gan/image_compression/testdata/')
+
+    batch_size = 3
+    patch_size = 8
+    images = data_provider.provide_data(
+        split_name, batch_size, dataset_dir, patch_size=8)
+    self.assertListEqual([batch_size, patch_size, patch_size, 3],
+                         images.shape.as_list())
+
+    with self.test_session(use_gpu=True) as sess:
+      with tf.contrib.slim.queues.QueueRunners(sess):
+        images_out = sess.run(images)
+        self.assertEqual((batch_size, patch_size, patch_size, 3),
+                         images_out.shape)
+        # Check range.
+        self.assertTrue(np.all(np.abs(images_out) <= 1.0))
+
+  def test_data_provider_train(self):
+    self._test_data_provider_helper('train')
+
+  def test_data_provider_validation(self):
+    self._test_data_provider_helper('validation')
+
+
+if __name__ == '__main__':
+  tf.test.main()

research/gan/image_compression/eval.py

+# Copyright 2017 The TensorFlow Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+"""Evaluates a TFGAN trained compression model."""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+
+
+import tensorflow as tf
+
+import data_provider
+import networks
+import summaries
+
+flags = tf.flags
+FLAGS = flags.FLAGS
+
+flags.DEFINE_string('master', '', 'Name of the TensorFlow master to use.')
+
+flags.DEFINE_string('checkpoint_dir', '/tmp/compression/',
+                    'Directory where the model was written to.')
+
+flags.DEFINE_string('eval_dir', '/tmp/compression/',
+                    'Directory where the results are saved to.')
+
+flags.DEFINE_integer('max_number_of_evaluations', None,
+                     'Number of times to run evaluation. If `None`, run '
+                     'forever.')
+
+flags.DEFINE_string('dataset_dir', None, 'Location of data.')
+
+# Compression-specific flags.
+flags.DEFINE_integer('batch_size', 32, 'The number of images in each batch.')
+
+flags.DEFINE_integer('patch_size', 32, 'The size of the patches to train on.')
+
+flags.DEFINE_integer('bits_per_patch', 1230,
+                     'The number of bits to produce per patch.')
+
+flags.DEFINE_integer('model_depth', 64,
+                     'Number of filters for compression model')
+
+
+def main(_, run_eval_loop=True):
+  with tf.name_scope('inputs'):
+    images = data_provider.provide_data(
+        'validation', FLAGS.batch_size, dataset_dir=FLAGS.dataset_dir,
+        patch_size=FLAGS.patch_size)
+
+  # In order for variables to load, use the same variable scope as in the
+  # train job.
+  with tf.variable_scope('generator'):
+    reconstructions, _, prebinary = networks.compression_model(
+        images,
+        num_bits=FLAGS.bits_per_patch,
+        depth=FLAGS.model_depth,
+        is_training=False)
+  summaries.add_reconstruction_summaries(images, reconstructions, prebinary)
+
+  # Visualize losses.
+  pixel_loss_per_example = tf.reduce_mean(
+      tf.abs(images - reconstructions), axis=[1, 2, 3])
+  pixel_loss = tf.reduce_mean(pixel_loss_per_example)
+  tf.summary.histogram('pixel_l1_loss_hist', pixel_loss_per_example)
+  tf.summary.scalar('pixel_l1_loss', pixel_loss)
+
+  # Create ops to write images to disk.
+  uint8_images = data_provider.float_image_to_uint8(images)
+  uint8_reconstructions = data_provider.float_image_to_uint8(reconstructions)
+  uint8_reshaped = summaries.stack_images(uint8_images, uint8_reconstructions)
+  image_write_ops = tf.write_file(
+      '%s/%s'% (FLAGS.eval_dir, 'compression.png'),
+      tf.image.encode_png(uint8_reshaped[0]))
+
+  # For unit testing, use `run_eval_loop=False`.
+  if not run_eval_loop: return
+  tf.contrib.training.evaluate_repeatedly(
+      FLAGS.checkpoint_dir,
+      master=FLAGS.master,
+      hooks=[tf.contrib.training.SummaryAtEndHook(FLAGS.eval_dir),
+             tf.contrib.training.StopAfterNEvalsHook(1)],
+      eval_ops=image_write_ops,
+      max_number_of_evaluations=FLAGS.max_number_of_evaluations)
+
+
+if __name__ == '__main__':
+  tf.app.run()

research/gan/image_compression/eval_test.py

+# Copyright 2017 The TensorFlow Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+"""Tests for gan.image_compression.eval."""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import tensorflow as tf
+import eval  # pylint:disable=redefined-builtin
+
+
+class EvalTest(tf.test.TestCase):
+
+  def test_build_graph(self):
+    eval.main(None, run_eval_loop=False)
+
+
+if __name__ == '__main__':
+  tf.test.main()