Merge pull request #1382 from rsepassi/adv_text

Add adversarial text model

adversarial_text/BUILD

+# Binaries
+# ==============================================================================
+py_binary(
+    name = "evaluate",
+    srcs = ["evaluate.py"],
+    deps = [
+        ":graphs",
+    ],
+)
+
+py_binary(
+    name = "train_classifier",
+    srcs = ["train_classifier.py"],
+    deps = [
+        ":graphs",
+        ":train_utils",
+    ],
+)
+
+py_binary(
+    name = "pretrain",
+    srcs = [
+        "pretrain.py",
+    ],
+    deps = [
+        ":graphs",
+        ":train_utils",
+    ],
+)
+
+# Libraries
+# ==============================================================================
+py_library(
+    name = "graphs",
+    srcs = ["graphs.py"],
+    deps = [
+        ":adversarial_losses",
+        ":inputs",
+        ":layers",
+    ],
+)
+
+py_library(
+    name = "adversarial_losses",
+    srcs = ["adversarial_losses.py"],
+)
+
+py_library(
+    name = "inputs",
+    srcs = ["inputs.py"],
+    deps = [
+        "//adversarial_text/data:data_utils",
+    ],
+)
+
+py_library(
+    name = "layers",
+    srcs = ["layers.py"],
+)
+
+py_library(
+    name = "train_utils",
+    srcs = ["train_utils.py"],
+)
+
+# Tests
+# ==============================================================================
+py_test(
+    name = "graphs_test",
+    size = "large",
+    srcs = ["graphs_test.py"],
+    deps = [
+        ":graphs",
+        "//adversarial_text/data:data_utils",
+    ],
+)

adversarial_text/README.md

+# Adversarial Text Classification
+
+Code for *Adversarial Training Methods for Semi-Supervised Text Classification*
+(https://arxiv.org/abs/1605.07725) and *Semi-Supervised Sequence Learning*
+(https://arxiv.org/abs/1511.01432).
+
+## Requirements
+
+* Bazel ([install](https://bazel.build/versions/master/docs/install.html))
+* TensorFlow >= v1.1
+
+## End-to-end IMDB Sentiment Classification
+
+### Fetch data
+
+```
+$ wget http://ai.stanford.edu/~amaas/data/sentiment/aclImdb_v1.tar.gz \
+    -O /tmp/imdb.tar.gz
+$ tar -xf /tmp/imdb.tar.gz -C /tmp
+```
+
+The directory `/tmp/aclImdb` contains the raw IMDB data.
+
+### Generate vocabulary
+
+```
+$ IMDB_DATA_DIR=/tmp/imdb
+$ bazel run data:gen_vocab -- \
+    --output_dir=$IMDB_DATA_DIR \
+    --dataset=imdb \
+    --imdb_input_dir=/tmp/aclImdb \
+    --lowercase=False
+```
+
+Vocabulary and frequency files will be generated in `$IMDB_DATA_DIR`.
+
+###  Generate training, validation, and test data
+
+```
+$ bazel run data:gen_data -- \
+    --output_dir=$IMDB_DATA_DIR \
+    --dataset=imdb \
+    --imdb_input_dir=/tmp/aclImdb \
+    --lowercase=False \
+    --label_gain=False
+```
+
+`$IMDB_DATA_DIR` contains TFRecords files.
+
+### Pretrain IMDB Language Model
+
+```
+$ PRETRAIN_DIR=/tmp/models/imdb_pretrain
+$ bazel run :pretrain -- \
+    --train_dir=$PRETRAIN_DIR \
+    --data_dir=$IMDB_DATA_DIR \
+    --vocab_size=86934 \
+    --embedding_dims=256 \
+    --rnn_cell_size=1024 \
+    --num_candidate_samples=1024 \
+    --optimizer=adam \
+    --batch_size=256 \
+    --learning_rate=0.001 \
+    --learning_rate_decay_factor=0.9999 \
+    --max_steps=100000 \
+    --max_grad_norm=1.0 \
+    --num_timesteps=400 \
+    --keep_prob_emb=0.5 \
+    --normalize_embeddings
+```
+
+`$PRETRAIN_DIR` contains checkpoints of the pretrained language model.
+
+### Train classifier
+
+Most flags stay the same, save for the removal of candidate sampling and the
+addition of `pretrained_model_dir`, from which the classifier will load the
+pretrained embedding and LSTM variables, and flags related to adversarial
+training and classification.
+
+```
+$ TRAIN_DIR=/tmp/models/imdb_classify
+$ bazel run :train_classifier -- \
+    --train_dir=$TRAIN_DIR \
+    --pretrained_model_dir=$PRETRAIN_DIR \
+    --data_dir=$IMDB_DATA_DIR \
+    --vocab_size=86934 \
+    --embedding_dims=256 \
+    --rnn_cell_size=1024 \
+    --cl_num_layers=1 \
+    --cl_hidden_size=30 \
+    --optimizer=adam \
+    --batch_size=64 \
+    --learning_rate=0.0005 \
+    --learning_rate_decay_factor=0.9998 \
+    --max_steps=15000 \
+    --max_grad_norm=1.0 \
+    --num_timesteps=400 \
+    --keep_prob_emb=0.5 \
+    --normalize_embeddings \
+    --adv_training_method=vat
+```
+
+### Evaluate on test data
+
+```
+$ EVAL_DIR=/tmp/models/imdb_eval
+$ bazel run :evaluate -- \
+    --eval_dir=$EVAL_DIR \
+    --checkpoint_dir=$TRAIN_DIR \
+    --eval_data=test \
+    --run_once \
+    --num_examples=25000 \
+    --data_dir=$IMDB_DATA_DIR \
+    --vocab_size=86934 \
+    --embedding_dims=256 \
+    --rnn_cell_size=1024 \
+    --batch_size=256 \
+    --num_timesteps=400 \
+    --normalize_embeddings
+```
+
+## Code Overview
+
+The main entry points are the binaries listed below. Each training binary builds
+a `VatxtModel`, defined in `graphs.py`, which in turn uses graph building blocks
+defined in `inputs.py` (defines input data reading and parsing), `layers.py`
+(defines core model components), and `adversarial_losses.py` (defines
+adversarial training losses). The training loop itself is defined in
+`train_utils.py`.
+
+### Binaries
+
+*   Pretraining: `pretrain.py`
+*   Classifier Training: `train_classifier.py`
+*   Evaluation: `evaluate.py`
+
+### Command-Line Flags
+
+Flags related to distributed training and the training loop itself are defined
+in `train_utils.py`.
+
+Flags related to model hyperparameters are defined in `graphs.py`.
+
+Flags related to adversarial training are defined in `adversarial_losses.py`.
+
+Flags particular to each job are defined in the main binary files.
+
+### Data Generation
+
+*   Vocabulary generation: `gen_vocab.py`
+*   Data generation: `gen_data.py`
+
+Command-line flags defined in `document_generators.py` control which dataset is
+processed and how.
+
+## Contact for Issues
+
+* Ryan Sepassi, @rsepassi

adversarial_text/adversarial_losses.py

+# Copyright 2017 Google, Inc. 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.
+# ==============================================================================
+
+"""Adversarial losses for text models."""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import tensorflow as tf
+
+flags = tf.app.flags
+FLAGS = flags.FLAGS
+
+# Adversarial and virtual adversarial training parameters.
+flags.DEFINE_float('perturb_norm_length', 0.1,
+                   'Norm length of adversarial perturbation to be '
+                   'optimized with validation')
+
+# Virtual adversarial training parameters
+flags.DEFINE_integer('num_power_iteration', 1, 'The number of power iteration')
+flags.DEFINE_float('small_constant_for_finite_diff', 1e-3,
+                   'Small constant for finite difference method')
+
+# Parameters for building the graph
+flags.DEFINE_string('adv_training_method', None,
+                    'The flag which specifies training method. '
+                    '"rp"  : random perturbation training '
+                    '"at"  : adversarial training '
+                    '"vat" : virtual adversarial training '
+                    '"atvat" : at + vat ')
+flags.DEFINE_float('adv_reg_coeff', 1.0,
+                   'Regularization coefficient of adversarial loss.')
+
+
+def random_perturbation_loss(embedded, length, loss_fn):
+  """Adds noise to embeddings and recomputes classification loss."""
+  noise = tf.random_normal(shape=tf.shape(embedded))
+  perturb = _scale_l2(_mask_by_length(noise, length), FLAGS.perturb_norm_length)
+  return loss_fn(embedded + perturb)
+
+
+def adversarial_loss(embedded, loss, loss_fn):
+  """Adds gradient to embedding and recomputes classification loss."""
+  grad, = tf.gradients(
+      loss,
+      embedded,
+      aggregation_method=tf.AggregationMethod.EXPERIMENTAL_ACCUMULATE_N)
+  grad = tf.stop_gradient(grad)
+  perturb = _scale_l2(grad, FLAGS.perturb_norm_length)
+  return loss_fn(embedded + perturb)
+
+
+def virtual_adversarial_loss(logits, embedded, inputs,
+                             logits_from_embedding_fn):
+  """Virtual adversarial loss.
+
+  Computes virtual adversarial perturbation by finite difference method and
+  power iteration, adds it to the embedding, and computes the KL divergence
+  between the new logits and the original logits.
+
+  Args:
+    logits: 2-D float Tensor, [num_timesteps*batch_size, m], where m=1 if
+      num_classes=2, otherwise m=num_classes.
+    embedded: 3-D float Tensor, [batch_size, num_timesteps, embedding_dim].
+    inputs: VatxtInput.
+    logits_from_embedding_fn: callable that takes embeddings and returns
+      classifier logits.
+
+  Returns:
+    kl: float scalar.
+  """
+  # Stop gradient of logits. See https://arxiv.org/abs/1507.00677 for details.
+  logits = tf.stop_gradient(logits)
+  weights = _end_of_seq_mask(inputs.labels)
+
+  # shape(embedded) = (batch_size, num_timesteps, embedding_dim)
+  d = _mask_by_length(tf.random_normal(shape=tf.shape(embedded)), inputs.length)
+
+  # Perform finite difference method and power iteration.
+  # See Eq.(8) in the paper http://arxiv.org/pdf/1507.00677.pdf,
+  # Adding small noise to input and taking gradient with respect to the noise
+  # corresponds to 1 power iteration.
+  for _ in xrange(FLAGS.num_power_iteration):
+    d = _scale_l2(d, FLAGS.small_constant_for_finite_diff)
+    d_logits = logits_from_embedding_fn(embedded + d)
+    kl = _kl_divergence_with_logits(logits, d_logits, weights)
+    d, = tf.gradients(
+        kl,
+        d,
+        aggregation_method=tf.AggregationMethod.EXPERIMENTAL_ACCUMULATE_N)
+    d = tf.stop_gradient(d)
+
+  perturb = _scale_l2(
+      _mask_by_length(d, inputs.length), FLAGS.perturb_norm_length)
+  vadv_logits = logits_from_embedding_fn(embedded + perturb)
+  return _kl_divergence_with_logits(logits, vadv_logits, weights)
+
+
+def random_perturbation_loss_bidir(embedded, length, loss_fn):
+  """Adds noise to embeddings and recomputes classification loss."""
+  noise = [tf.random_normal(shape=tf.shape(emb)) for emb in embedded]
+  masked = [_mask_by_length(n, length) for n in noise]
+  scaled = [_scale_l2(m, FLAGS.perturb_norm_length) for m in masked]
+  return loss_fn([e + s for (e, s) in zip(embedded, scaled)])
+
+
+def adversarial_loss_bidir(embedded, loss, loss_fn):
+  """Adds gradient to embeddings and recomputes classification loss."""
+  grads = tf.gradients(
+      loss,
+      embedded,
+      aggregation_method=tf.AggregationMethod.EXPERIMENTAL_ACCUMULATE_N)
+  adv_exs = [
+      emb + _scale_l2(tf.stop_gradient(g), FLAGS.perturb_norm_length)
+      for emb, g in zip(embedded, grads)
+  ]
+  return loss_fn(adv_exs)
+
+
+def virtual_adversarial_loss_bidir(logits, embedded, inputs,
+                                   logits_from_embedding_fn):
+  """Virtual adversarial loss for bidirectional models."""
+  logits = tf.stop_gradient(logits)
+  f_inputs, _ = inputs
+  weights = _end_of_seq_mask(f_inputs.labels)
+
+  perturbs = [
+      _mask_by_length(tf.random_normal(shape=tf.shape(emb)), f_inputs.length)
+      for emb in embedded
+  ]
+  for _ in xrange(FLAGS.num_power_iteration):
+    perturbs = [
+        _scale_l2(d, FLAGS.small_constant_for_finite_diff) for d in perturbs
+    ]
+    d_logits = logits_from_embedding_fn(
+        [emb + d for (emb, d) in zip(embedded, perturbs)])
+    kl = _kl_divergence_with_logits(logits, d_logits, weights)
+    perturbs = tf.gradients(
+        kl,
+        perturbs,
+        aggregation_method=tf.AggregationMethod.EXPERIMENTAL_ACCUMULATE_N)
+    perturbs = [tf.stop_gradient(d) for d in perturbs]
+
+  perturbs = [
+      _scale_l2(_mask_by_length(d, f_inputs.length), FLAGS.perturb_norm_length)
+      for d in perturbs
+  ]
+  vadv_logits = logits_from_embedding_fn(
+      [emb + d for (emb, d) in zip(embedded, perturbs)])
+  return _kl_divergence_with_logits(logits, vadv_logits, weights)
+
+
+def _mask_by_length(t, length):
+  """Mask t, 3-D [batch, time, dim], by length, 1-D [batch,]."""
+  maxlen = t.get_shape().as_list()[1]
+  mask = tf.sequence_mask(length, maxlen=maxlen)
+  mask = tf.expand_dims(tf.cast(mask, tf.float32), -1)
+  # shape(mask) = (batch, num_timesteps, 1)
+  return t * mask
+
+
+def _scale_l2(x, norm_length):
+  # shape(x) = (batch, num_timesteps, d)
+  x /= (1e-12 + tf.reduce_max(tf.abs(x), 2, keep_dims=True))
+  x_2 = tf.reduce_sum(tf.pow(x, 2), 2, keep_dims=True)
+  x /= tf.sqrt(1e-6 + x_2)
+
+  return norm_length * x
+
+
+def _end_of_seq_mask(tokens):
+  """Generate a mask for the EOS token (1.0 on EOS, 0.0 otherwise).
+
+  Args:
+    tokens: 1-D integer tensor [num_timesteps*batch_size]. Each element is an
+      id from the vocab.
+
+  Returns:
+    Float tensor same shape as tokens, whose values are 1.0 on the end of
+    sequence and 0.0 on the others.
+  """
+  eos_id = FLAGS.vocab_size - 1
+  return tf.cast(tf.equal(tokens, eos_id), tf.float32)
+
+
+def _kl_divergence_with_logits(q_logits, p_logits, weights):
+  """Returns weighted KL divergence between distributions q and p.
+
+  Args:
+    q_logits: logits for 1st argument of KL divergence shape
+              [num_timesteps * batch_size, num_classes] if num_classes > 2, and
+              [num_timesteps * batch_size] if num_classes == 2.
+    p_logits: logits for 2nd argument of KL divergence with same shape q_logits.
+    weights: 1-D float tensor with shape [num_timesteps * batch_size].
+             Elements should be 1.0 only on end of sequences
+
+  Returns:
+    KL: float scalar.
+  """
+  # For logistic regression
+  if FLAGS.num_classes == 2:
+    q = tf.nn.sigmoid(q_logits)
+    p = tf.nn.sigmoid(p_logits)
+    kl = (-tf.nn.sigmoid_cross_entropy_with_logits(logits=q_logits, labels=q) +
+          tf.nn.sigmoid_cross_entropy_with_logits(logits=p_logits, labels=q))
+
+  # For softmax regression
+  else:
+    q = tf.nn.softmax(q_logits)
+    p = tf.nn.softmax(p_logits)
+    kl = tf.reduce_sum(q * (tf.log(q) - tf.log(p)), 1)
+
+  num_labels = tf.reduce_sum(weights)
+  num_labels = tf.where(tf.equal(num_labels, 0.), 1., num_labels)
+
+  loss = tf.identity(tf.reduce_sum(weights * kl) / num_labels, name='kl')
+  return loss

adversarial_text/data/BUILD

+package(
+    default_visibility = [
+        "//adversarial_text:__subpackages__",
+    ],
+)
+
+py_binary(
+    name = "gen_vocab",
+    srcs = ["gen_vocab.py"],
+    deps = [
+        ":data_utils",
+        ":document_generators",
+    ],
+)
+
+py_binary(
+    name = "gen_data",
+    srcs = ["gen_data.py"],
+    deps = [
+        ":data_utils",
+        ":document_generators",
+    ],
+)
+
+py_library(
+    name = "document_generators",
+    srcs = ["document_generators.py"],
+)
+
+py_library(
+    name = "data_utils",
+    srcs = ["data_utils.py"],
+)
+
+py_test(
+    name = "data_utils_test",
+    srcs = ["data_utils_test.py"],
+    deps = [
+        ":data_utils",
+    ],
+)

adversarial_text/data/data_utils.py

+# Copyright 2017 Google, Inc. 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.
+# ==============================================================================
+
+"""Utilities for generating/preprocessing data for adversarial text models."""
+
+import operator
+import os
+import random
+import re
+import tensorflow as tf
+
+EOS_TOKEN = '</s>'
+
+# Data filenames
+# Sequence Autoencoder
+ALL_SA = 'all_sa.tfrecords'
+TRAIN_SA = 'train_sa.tfrecords'
+TEST_SA = 'test_sa.tfrecords'
+# Language Model
+ALL_LM = 'all_lm.tfrecords'
+TRAIN_LM = 'train_lm.tfrecords'
+TEST_LM = 'test_lm.tfrecords'
+# Classification
+TRAIN_CLASS = 'train_classification.tfrecords'
+TEST_CLASS = 'test_classification.tfrecords'
+VALID_CLASS = 'validate_classification.tfrecords'
+# LM with bidirectional LSTM
+TRAIN_REV_LM = 'train_reverse_lm.tfrecords'
+TEST_REV_LM = 'test_reverse_lm.tfrecords'
+# Classification with bidirectional LSTM
+TRAIN_BD_CLASS = 'train_bidir_classification.tfrecords'
+TEST_BD_CLASS = 'test_bidir_classification.tfrecords'
+VALID_BD_CLASS = 'validate_bidir_classification.tfrecords'
+
+
+class ShufflingTFRecordWriter(object):
+  """Thin wrapper around TFRecordWriter that shuffles records."""
+
+  def __init__(self, path):
+    self._path = path
+    self._records = []
+    self._closed = False
+
+  def write(self, record):
+    assert not self._closed
+    self._records.append(record)
+
+  def close(self):
+    assert not self._closed
+    random.shuffle(self._records)
+    with tf.python_io.TFRecordWriter(self._path) as f:
+      for record in self._records:
+        f.write(record)
+    self._closed = True
+
+  def __enter__(self):
+    return self
+
+  def __exit__(self, unused_type, unused_value, unused_traceback):
+    self.close()
+
+
+class Timestep(object):
+  """Represents a single timestep in a SequenceWrapper."""
+
+  def __init__(self, token, label, weight, multivalent_tokens=False):
+    """Constructs Timestep from empty Features."""
+    self._token = token
+    self._label = label
+    self._weight = weight
+    self._multivalent_tokens = multivalent_tokens
+    self._fill_with_defaults()
+
+  @property
+  def token(self):
+    if self._multivalent_tokens:
+      raise TypeError('Timestep may contain multiple values; use `tokens`')
+    return self._token.int64_list.value[0]
+
+  @property
+  def tokens(self):
+    return self._token.int64_list.value
+
+  @property
+  def label(self):
+    return self._label.int64_list.value[0]
+
+  @property
+  def weight(self):
+    return self._weight.float_list.value[0]
+
+  def set_token(self, token):
+    if self._multivalent_tokens:
+      raise TypeError('Timestep may contain multiple values; use `add_token`')
+    self._token.int64_list.value[0] = token
+    return self
+
+  def add_token(self, token):
+    self._token.int64_list.value.append(token)
+    return self
+
+  def set_label(self, label):
+    self._label.int64_list.value[0] = label
+    return self
+
+  def set_weight(self, weight):
+    self._weight.float_list.value[0] = weight
+    return self
+
+  def copy_from(self, timestep):
+    self.set_token(timestep.token).set_label(timestep.label).set_weight(
+        timestep.weight)
+    return self
+
+  def _fill_with_defaults(self):
+    if not self._multivalent_tokens:
+      self._token.int64_list.value.append(0)
+    self._label.int64_list.value.append(0)
+    self._weight.float_list.value.append(0.0)
+
+
+class SequenceWrapper(object):
+  """Wrapper around tf.SequenceExample."""
+
+  F_TOKEN_ID = 'token_id'
+  F_LABEL = 'label'
+  F_WEIGHT = 'weight'
+
+  def __init__(self, multivalent_tokens=False):
+    self._seq = tf.train.SequenceExample()
+    self._flist = self._seq.feature_lists.feature_list
+    self._timesteps = []
+    self._multivalent_tokens = multivalent_tokens
+
+  @property
+  def seq(self):
+    return self._seq
+
+  @property
+  def multivalent_tokens(self):
+    return self._multivalent_tokens
+
+  @property
+  def _tokens(self):
+    return self._flist[SequenceWrapper.F_TOKEN_ID].feature
+
+  @property
+  def _labels(self):
+    return self._flist[SequenceWrapper.F_LABEL].feature
+
+  @property
+  def _weights(self):
+    return self._flist[SequenceWrapper.F_WEIGHT].feature
+
+  def add_timestep(self):
+    timestep = Timestep(
+        self._tokens.add(),
+        self._labels.add(),
+        self._weights.add(),
+        multivalent_tokens=self._multivalent_tokens)
+    self._timesteps.append(timestep)
+    return timestep
+
+  def __iter__(self):
+    for timestep in self._timesteps:
+      yield timestep
+
+  def __len__(self):
+    return len(self._timesteps)
+
+  def __getitem__(self, idx):
+    return self._timesteps[idx]
+
+
+def build_reverse_sequence(seq):
+  """Builds a sequence that is the reverse of the input sequence."""
+  reverse_seq = SequenceWrapper()
+
+  # Copy all but last timestep
+  for timestep in reversed(seq[:-1]):
+    reverse_seq.add_timestep().copy_from(timestep)
+
+  # Copy final timestep
+  reverse_seq.add_timestep().copy_from(seq[-1])
+
+  return reverse_seq
+
+
+def build_bidirectional_seq(seq, rev_seq):
+  bidir_seq = SequenceWrapper(multivalent_tokens=True)
+  for forward_ts, reverse_ts in zip(seq, rev_seq):
+    bidir_seq.add_timestep().add_token(forward_ts.token).add_token(
+        reverse_ts.token)
+
+  return bidir_seq
+
+
+def build_lm_sequence(seq):
+  """Builds language model sequence from input sequence.
+
+  Args:
+    seq: SequenceWrapper.
+
+  Returns:
+    SequenceWrapper with `seq` tokens copied over to output sequence tokens and
+    labels (offset by 1, i.e. predict next token) with weights set to 1.0.
+  """
+  lm_seq = SequenceWrapper()
+  for i, timestep in enumerate(seq[:-1]):
+    lm_seq.add_timestep().set_token(timestep.token).set_label(
+        seq[i + 1].token).set_weight(1.0)
+
+  return lm_seq
+
+
+def build_seq_ae_sequence(seq):
+  """Builds seq_ae sequence from input sequence.
+
+  Args:
+    seq: SequenceWrapper.
+
+  Returns:
+    SequenceWrapper with `seq` inputs copied and concatenated, and with labels
+    copied in on the right-hand (i.e. decoder) side with weights set to 1.0.
+    The new sequence will have length `len(seq) * 2 - 1`, as the last timestep
+    of the encoder section and the first step of the decoder section will
+    overlap.
+  """
+  seq_ae_seq = SequenceWrapper()
+
+  for i in range(len(seq) * 2 - 1):
+    ts = seq_ae_seq.add_timestep()
+
+    if i < len(seq) - 1:
+      # Encoder
+      ts.set_token(seq[i].token)
+    elif i == len(seq) - 1:
+      # Transition step
+      ts.set_token(seq[i].token)
+      ts.set_label(seq[0].token)
+      ts.set_weight(1.0)
+    else:
+      # Decoder
+      ts.set_token(seq[i % len(seq)].token)
+      ts.set_label(seq[(i + 1) % len(seq)].token)
+      ts.set_weight(1.0)
+
+  return seq_ae_seq
+
+
+def build_labeled_sequence(seq, class_label, label_gain=False):
+  """Builds labeled sequence from input sequence.
+
+  Args:
+    seq: SequenceWrapper.
+    class_label: bool.
+    label_gain: bool. If True, class_label will be put on every timestep and
+      weight will increase linearly from 0 to 1.
+
+  Returns:
+    SequenceWrapper with `seq` copied in and `class_label` added as label to
+    final timestep.
+  """
+  label_seq = SequenceWrapper(multivalent_tokens=seq.multivalent_tokens)
+
+  # Copy sequence without labels
+  seq_len = len(seq)
+  final_timestep = None
+  for i, timestep in enumerate(seq):
+    label_timestep = label_seq.add_timestep()
+    if seq.multivalent_tokens:
+      for token in timestep.tokens:
+        label_timestep.add_token(token)
+    else:
+      label_timestep.set_token(timestep.token)
+    if label_gain:
+      label_timestep.set_label(int(class_label))
+      weight = 1.0 if seq_len < 2 else float(i) / (seq_len - 1)
+      label_timestep.set_weight(weight)
+    if i == (seq_len - 1):
+      final_timestep = label_timestep
+
+  # Edit final timestep to have class label and weight = 1.
+  final_timestep.set_label(int(class_label)).set_weight(1.0)
+
+  return label_seq
+
+
+def split_by_punct(segment):
+  """Splits str segment by punctuation, filters our empties and spaces."""
+  return [s for s in re.split(r'\W+', segment) if s and not s.isspace()]
+
+
+def sort_vocab_by_frequency(vocab_freq_map):
+  """Sorts vocab_freq_map by count.
+
+  Args:
+    vocab_freq_map: dict<str term, int count>, vocabulary terms with counts.
+
+  Returns:
+    list<tuple<str term, int count>> sorted by count, descending.
+  """
+  return sorted(
+      vocab_freq_map.items(), key=operator.itemgetter(1), reverse=True)
+
+
+def write_vocab_and_frequency(ordered_vocab_freqs, output_dir):
+  """Writes ordered_vocab_freqs into vocab.txt and vocab_freq.txt."""
+  tf.gfile.MakeDirs(output_dir)
+  with open(os.path.join(output_dir, 'vocab.txt'), 'w') as vocab_f:
+    with open(os.path.join(output_dir, 'vocab_freq.txt'), 'w') as freq_f:
+      for word, freq in ordered_vocab_freqs:
+        vocab_f.write('{}\n'.format(word))
+        freq_f.write('{}\n'.format(freq))

adversarial_text/data/data_utils_test.py

+# Copyright 2017 Google, Inc. 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_utils."""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import tensorflow as tf
+
+from adversarial_text.data import data_utils
+
+data = data_utils
+
+
+class SequenceWrapperTest(tf.test.TestCase):
+
+  def testDefaultTimesteps(self):
+    seq = data.SequenceWrapper()
+    t1 = seq.add_timestep()
+    _ = seq.add_timestep()
+    self.assertEqual(len(seq), 2)
+
+    self.assertEqual(t1.weight, 0.0)
+    self.assertEqual(t1.label, 0)
+    self.assertEqual(t1.token, 0)
+
+  def testSettersAndGetters(self):
+    ts = data.SequenceWrapper().add_timestep()
+    ts.set_token(3)
+    ts.set_label(4)
+    ts.set_weight(2.0)
+    self.assertEqual(ts.token, 3)
+    self.assertEqual(ts.label, 4)
+    self.assertEqual(ts.weight, 2.0)
+
+  def testTimestepIteration(self):
+    seq = data.SequenceWrapper()
+    seq.add_timestep().set_token(0)
+    seq.add_timestep().set_token(1)
+    seq.add_timestep().set_token(2)
+    for i, ts in enumerate(seq):
+      self.assertEqual(ts.token, i)
+
+  def testFillsSequenceExampleCorrectly(self):
+    seq = data.SequenceWrapper()
+    seq.add_timestep().set_token(1).set_label(2).set_weight(3.0)
+    seq.add_timestep().set_token(10).set_label(20).set_weight(30.0)
+
+    seq_ex = seq.seq
+    fl = seq_ex.feature_lists.feature_list
+    fl_token = fl[data.SequenceWrapper.F_TOKEN_ID].feature
+    fl_label = fl[data.SequenceWrapper.F_LABEL].feature
+    fl_weight = fl[data.SequenceWrapper.F_WEIGHT].feature
+    _ = [self.assertEqual(len(f), 2) for f in [fl_token, fl_label, fl_weight]]
+    self.assertAllEqual([f.int64_list.value[0] for f in fl_token], [1, 10])
+    self.assertAllEqual([f.int64_list.value[0] for f in fl_label], [2, 20])
+    self.assertAllEqual([f.float_list.value[0] for f in fl_weight], [3.0, 30.0])
+
+
+class DataUtilsTest(tf.test.TestCase):
+
+  def testSplitByPunct(self):
+    output = data.split_by_punct(
+        'hello! world, i\'ve been\nwaiting\tfor\ryou for.a long time')
+    expected = [
+        'hello', 'world', 'i', 've', 'been', 'waiting', 'for', 'you', 'for',
+        'a', 'long', 'time'
+    ]
+    self.assertListEqual(output, expected)
+
+  def _buildDummySequence(self):
+    seq = data.SequenceWrapper()
+    for i in range(10):
+      seq.add_timestep().set_token(i)
+    return seq
+
+  def testBuildLMSeq(self):
+    seq = self._buildDummySequence()
+    lm_seq = data.build_lm_sequence(seq)
+    for i, ts in enumerate(lm_seq):
+      self.assertEqual(ts.token, i)
+      self.assertEqual(ts.label, i + 1)
+      self.assertEqual(ts.weight, 1.0)
+
+  def testBuildSAESeq(self):
+    seq = self._buildDummySequence()
+    sa_seq = data.build_seq_ae_sequence(seq)
+
+    self.assertEqual(len(sa_seq), len(seq) * 2 - 1)
+
+    # Tokens should be sequence twice, minus the EOS token at the end
+    for i, ts in enumerate(sa_seq):
+      self.assertEqual(ts.token, seq[i % 10].token)
+
+    # Weights should be len-1 0.0's and len 1.0's.
+    for i in range(len(seq) - 1):
+      self.assertEqual(sa_seq[i].weight, 0.0)
+    for i in range(len(seq) - 1, len(sa_seq)):
+      self.assertEqual(sa_seq[i].weight, 1.0)
+
+    # Labels should be len-1 0's, and then the sequence
+    for i in range(len(seq) - 1):
+      self.assertEqual(sa_seq[i].label, 0)
+    for i in range(len(seq) - 1, len(sa_seq)):
+      self.assertEqual(sa_seq[i].label, seq[i - (len(seq) - 1)].token)
+
+  def testBuildLabelSeq(self):
+    seq = self._buildDummySequence()
+    eos_id = len(seq) - 1
+    label_seq = data.build_labeled_sequence(seq, True)
+    for i, ts in enumerate(label_seq[:-1]):
+      self.assertEqual(ts.token, i)
+      self.assertEqual(ts.label, 0)
+      self.assertEqual(ts.weight, 0.0)
+
+    final_timestep = label_seq[-1]
+    self.assertEqual(final_timestep.token, eos_id)
+    self.assertEqual(final_timestep.label, 1)
+    self.assertEqual(final_timestep.weight, 1.0)
+
+  def testBuildBidirLabelSeq(self):
+    seq = self._buildDummySequence()
+    reverse_seq = data.build_reverse_sequence(seq)
+    bidir_seq = data.build_bidirectional_seq(seq, reverse_seq)
+    label_seq = data.build_labeled_sequence(bidir_seq, True)
+
+    for (i, ts), j in zip(
+        enumerate(label_seq[:-1]), reversed(range(len(seq) - 1))):
+      self.assertAllEqual(ts.tokens, [i, j])
+      self.assertEqual(ts.label, 0)
+      self.assertEqual(ts.weight, 0.0)
+
+    final_timestep = label_seq[-1]
+    eos_id = len(seq) - 1
+    self.assertAllEqual(final_timestep.tokens, [eos_id, eos_id])
+    self.assertEqual(final_timestep.label, 1)
+    self.assertEqual(final_timestep.weight, 1.0)
+
+  def testReverseSeq(self):
+    seq = self._buildDummySequence()
+    reverse_seq = data.build_reverse_sequence(seq)
+    for i, ts in enumerate(reversed(reverse_seq[:-1])):
+      self.assertEqual(ts.token, i)
+      self.assertEqual(ts.label, 0)
+      self.assertEqual(ts.weight, 0.0)
+
+    final_timestep = reverse_seq[-1]
+    eos_id = len(seq) - 1
+    self.assertEqual(final_timestep.token, eos_id)
+    self.assertEqual(final_timestep.label, 0)
+    self.assertEqual(final_timestep.weight, 0.0)
+
+  def testBidirSeq(self):
+    seq = self._buildDummySequence()
+    reverse_seq = data.build_reverse_sequence(seq)
+    bidir_seq = data.build_bidirectional_seq(seq, reverse_seq)
+    for (i, ts), j in zip(
+        enumerate(bidir_seq[:-1]), reversed(range(len(seq) - 1))):
+      self.assertAllEqual(ts.tokens, [i, j])
+      self.assertEqual(ts.label, 0)
+      self.assertEqual(ts.weight, 0.0)
+
+    final_timestep = bidir_seq[-1]
+    eos_id = len(seq) - 1
+    self.assertAllEqual(final_timestep.tokens, [eos_id, eos_id])
+    self.assertEqual(final_timestep.label, 0)
+    self.assertEqual(final_timestep.weight, 0.0)
+
+  def testLabelGain(self):
+    seq = self._buildDummySequence()
+    label_seq = data.build_labeled_sequence(seq, True, label_gain=True)
+    for i, ts in enumerate(label_seq):
+      self.assertEqual(ts.token, i)
+      self.assertEqual(ts.label, 1)
+      self.assertNear(ts.weight, float(i) / (len(seq) - 1), 1e-3)
+
+
+if __name__ == '__main__':
+  tf.test.main()

adversarial_text/data/document_generators.py

+# Copyright 2017 Google, Inc. 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.
+# ==============================================================================
+
+"""Input readers and document/token generators for datasets."""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+from collections import namedtuple
+import csv
+import os
+import random
+
+import tensorflow as tf
+
+from adversarial_text.data import data_utils
+
+flags = tf.app.flags
+FLAGS = flags.FLAGS
+
+flags.DEFINE_string('dataset', '', 'Which dataset to generate data for')
+
+# Preprocessing config
+flags.DEFINE_boolean('output_unigrams', True, 'Whether to output unigrams.')
+flags.DEFINE_boolean('output_bigrams', False, 'Whether to output bigrams.')
+flags.DEFINE_boolean('output_char', False, 'Whether to output characters.')
+flags.DEFINE_boolean('lowercase', True, 'Whether to lowercase document terms.')
+
+# IMDB
+flags.DEFINE_string('imdb_input_dir', '', 'The input directory containing the '
+                    'IMDB sentiment dataset.')
+flags.DEFINE_integer('imdb_validation_pos_start_id', 10621, 'File id of the '
+                     'first file in the pos sentiment validation set.')
+flags.DEFINE_integer('imdb_validation_neg_start_id', 10625, 'File id of the '
+                     'first file in the neg sentiment validation set.')
+
+# DBpedia
+flags.DEFINE_string('dbpedia_input_dir', '',
+                    'Path to DBpedia directory containing train.csv and '
+                    'test.csv.')
+
+# Reuters Corpus (rcv1)
+flags.DEFINE_string('rcv1_input_dir', '',
+                    'Path to rcv1 directory containing train.csv, unlab.csv, '
+                    'and test.csv.')
+
+# Rotten Tomatoes
+flags.DEFINE_string('rt_input_dir', '',
+                    'The Rotten Tomatoes dataset input directory.')
+
+
+# The amazon reviews input file to use in either the RT or IMDB datasets.
+flags.DEFINE_string('amazon_unlabeled_input_file', '',
+                    'The unlabeled Amazon Reviews dataset input file. If set, '
+                    'the input file is used to augment RT and IMDB vocab.')
+
+Document = namedtuple('Document',
+                      'content is_validation is_test label add_tokens')
+
+
+def documents(dataset='train',
+              include_unlabeled=False,
+              include_validation=False):
+  """Generates Documents based on FLAGS.dataset.
+
+  Args:
+    dataset: str, identifies folder within IMDB data directory, test or train.
+    include_unlabeled: bool, whether to include the unsup directory. Only valid
+      when dataset=train.
+    include_validation: bool, whether to include validation data.
+
+  Yields:
+    Document
+
+  Raises:
+    ValueError: if include_unlabeled is true but dataset is not 'train'
+  """
+
+  if include_unlabeled and dataset != 'train':
+    raise ValueError('If include_unlabeled=True, must use train dataset')
+
+  # Set the random seed so that we have the same validation set when running
+  # gen_data and gen_vocab.
+  random.seed(302)
+
+  ds = FLAGS.dataset
+  if ds == 'imdb':
+    docs_gen = imdb_documents
+  elif ds == 'dbpedia':
+    docs_gen = dbpedia_documents
+  elif ds == 'rcv1':
+    docs_gen = rcv1_documents
+  elif ds == 'rt':
+    docs_gen = rt_documents
+  else:
+    raise ValueError('Unrecognized dataset %s' % FLAGS.dataset)
+
+  for doc in docs_gen(dataset, include_unlabeled, include_validation):
+    yield doc
+
+
+def tokens(doc):
+  """Given a Document, produces character or word tokens.
+
+  Tokens can be either characters, or word-level tokens (unigrams and/or
+  bigrams).
+
+  Args:
+    doc: Document to produce tokens from.
+
+  Yields:
+    token
+
+  Raises:
+    ValueError: if all FLAGS.{output_unigrams, output_bigrams, output_char}
+      are False.
+  """
+  if not (FLAGS.output_unigrams or FLAGS.output_bigrams or FLAGS.output_char):
+    raise ValueError(
+        'At least one of {FLAGS.output_unigrams, FLAGS.output_bigrams, '
+        'FLAGS.output_char} must be true')
+
+  content = doc.content.strip()
+  if FLAGS.lowercase:
+    content = content.lower()
+
+  if FLAGS.output_char:
+    for char in content:
+      yield char
+
+  else:
+    tokens_ = data_utils.split_by_punct(content)
+    for i, token in enumerate(tokens_):
+      if FLAGS.output_unigrams:
+        yield token
+
+      if FLAGS.output_bigrams:
+        previous_token = (tokens_[i - 1] if i > 0 else data_utils.EOS_TOKEN)
+        bigram = '_'.join([previous_token, token])
+        yield bigram
+        if (i + 1) == len(tokens_):
+          bigram = '_'.join([token, data_utils.EOS_TOKEN])
+          yield bigram
+
+
+def imdb_documents(dataset='train',
+                   include_unlabeled=False,
+                   include_validation=False):
+  """Generates Documents for IMDB dataset.
+
+  Data from http://ai.stanford.edu/~amaas/data/sentiment/
+
+  Args:
+    dataset: str, identifies folder within IMDB data directory, test or train.
+    include_unlabeled: bool, whether to include the unsup directory. Only valid
+      when dataset=train.
+    include_validation: bool, whether to include validation data.
+
+  Yields:
+    Document
+
+  Raises:
+    ValueError: if FLAGS.imdb_input_dir is empty.
+  """
+  if not FLAGS.imdb_input_dir:
+    raise ValueError('Must provide FLAGS.imdb_input_dir')
+
+  tf.logging.info('Generating IMDB documents...')
+
+  def check_is_validation(filename, class_label):
+    if class_label is None:
+      return False
+    file_idx = int(filename.split('_')[0])
+    is_pos_valid = (class_label and
+                    file_idx >= FLAGS.imdb_validation_pos_start_id)
+    is_neg_valid = (not class_label and
+                    file_idx >= FLAGS.imdb_validation_neg_start_id)
+    return is_pos_valid or is_neg_valid
+
+  dirs = [(dataset + '/pos', True), (dataset + '/neg', False)]
+  if include_unlabeled:
+    dirs.append(('train/unsup', None))
+
+  for d, class_label in dirs:
+    for filename in os.listdir(os.path.join(FLAGS.imdb_input_dir, d)):
+      is_validation = check_is_validation(filename, class_label)
+      if is_validation and not include_validation:
+        continue
+
+      with open(os.path.join(FLAGS.imdb_input_dir, d, filename)) as imdb_f:
+        content = imdb_f.read()
+      yield Document(
+          content=content,
+          is_validation=is_validation,
+          is_test=False,
+          label=class_label,
+          add_tokens=True)
+
+  if FLAGS.amazon_unlabeled_input_file and include_unlabeled:
+    with open(FLAGS.amazon_unlabeled_input_file) as rt_f:
+      for content in rt_f:
+        yield Document(content=content, is_validation=False, is_test=False,
+                       label=None, add_tokens=False)
+
+
+def dbpedia_documents(dataset='train',
+                      include_unlabeled=False,
+                      include_validation=False):
+  """Generates Documents for DBpedia dataset.
+
+  Dataset linked to at https://github.com/zhangxiangxiao/Crepe.
+
+  Args:
+    dataset: str, identifies the csv file within the DBpedia data directory,
+      test or train.
+    include_unlabeled: bool, unused.
+    include_validation: bool, whether to include validation data, which is a
+      randomly selected 10% of the data.
+
+  Yields:
+    Document
+
+  Raises:
+    ValueError: if FLAGS.dbpedia_input_dir is empty.
+  """
+  del include_unlabeled
+
+  if not FLAGS.dbpedia_input_dir:
+    raise ValueError('Must provide FLAGS.dbpedia_input_dir')
+
+  tf.logging.info('Generating DBpedia documents...')
+
+  with open(os.path.join(FLAGS.dbpedia_input_dir, dataset + '.csv')) as db_f:
+    reader = csv.reader(db_f)
+    for row in reader:
+      # 10% of the data is randomly held out
+      is_validation = random.randint(1, 10) == 1
+      if is_validation and not include_validation:
+        continue
+
+      content = row[1] + ' ' + row[2]
+      yield Document(
+          content=content,
+          is_validation=is_validation,
+          is_test=False,
+          label=int(row[0]),
+          add_tokens=True)
+
+
+def rcv1_documents(dataset='train',
+                   include_unlabeled=True,
+                   include_validation=False):
+  # pylint:disable=line-too-long
+  """Generates Documents for Reuters Corpus (rcv1) dataset.
+
+  Dataset described at http://www.ai.mit.edu/projects/jmlr/papers/volume5/lewis04a/lyrl2004_rcv1v2_README.htm
+
+  Args:
+    dataset: str, identifies the csv file within the rcv1 data directory.
+    include_unlabeled: bool, whether to include the unlab file. Only valid
+      when dataset=train.
+    include_validation: bool, whether to include validation data, which is a
+      randomly selected 10% of the data.
+
+  Yields:
+    Document
+
+  Raises:
+    ValueError: if FLAGS.rcv1_input_dir is empty.
+  """
+  # pylint:enable=line-too-long
+
+  if not FLAGS.rcv1_input_dir:
+    raise ValueError('Must provide FLAGS.rcv1_input_dir')
+
+  tf.logging.info('Generating rcv1 documents...')
+
+  datasets = [dataset]
+  if include_unlabeled:
+    if dataset == 'train':
+      datasets.append('unlab')
+  for dset in datasets:
+    with open(os.path.join(FLAGS.rcv1_input_dir, dset + '.csv')) as db_f:
+      reader = csv.reader(db_f)
+      for row in reader:
+        # 10% of the data is randomly held out
+        is_validation = random.randint(1, 10) == 1
+        if is_validation and not include_validation:
+          continue
+
+        content = row[1]
+        yield Document(
+            content=content,
+            is_validation=is_validation,
+            is_test=False,
+            label=int(row[0]),
+            add_tokens=True)
+
+
+def rt_documents(dataset='train',
+                 include_unlabeled=True,
+                 include_validation=False):
+  # pylint:disable=line-too-long
+  """Generates Documents for the Rotten Tomatoes dataset.
+
+  Dataset available at http://www.cs.cornell.edu/people/pabo/movie-review-data/
+  In this dataset, amazon reviews are used for the unlabeled data.
+
+  Args:
+    dataset: str, identifies the data subdirectory.
+    include_unlabeled: bool, whether to include the unlabeled data. Only valid
+      when dataset=train.
+    include_validation: bool, whether to include validation data, which is a
+      randomly selected 10% of the data.
+
+  Yields:
+    Document
+
+  Raises:
+    ValueError: if FLAGS.rt_input_dir is empty.
+  """
+  # pylint:enable=line-too-long
+
+  if not FLAGS.rt_input_dir:
+    raise ValueError('Must provide FLAGS.rt_input_dir')
+
+  tf.logging.info('Generating rt documents...')
+
+  data_files = []
+  input_filenames = os.listdir(FLAGS.rt_input_dir)
+  for inp_fname in input_filenames:
+    if inp_fname.endswith('.pos'):
+      data_files.append((os.path.join(FLAGS.rt_input_dir, inp_fname), True))
+    elif inp_fname.endswith('.neg'):
+      data_files.append((os.path.join(FLAGS.rt_input_dir, inp_fname), False))
+  if include_unlabeled and FLAGS.amazon_unlabeled_input_file:
+    data_files.append((FLAGS.amazon_unlabeled_input_file, None))
+
+  for filename, class_label in data_files:
+    with open(filename) as rt_f:
+      for content in rt_f:
+        if class_label is None:
+          # Process Amazon Review data for unlabeled dataset
+          if content.startswith('review/text'):
+            yield Document(content=content, is_validation=False,
+                           is_test=False, label=None, add_tokens=False)
+        else:
+          # 10% of the data is randomly held out for the validation set and
+          # another 10% of it is randomly held out for the test set
+          random_int = random.randint(1, 10)
+          is_validation = random_int == 1
+          is_test = random_int == 2
+          if (is_test and dataset != 'test') or (
+              is_validation and not include_validation):
+            continue
+
+          yield Document(content=content, is_validation=is_validation,
+                         is_test=is_test, label=class_label, add_tokens=True)

adversarial_text/data/gen_data.py

+# Copyright 2017 Google, Inc. 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.
+# ==============================================================================
+
+"""Create TFRecord files of SequenceExample protos from dataset.
+
+Constructs 3 datasets:
+  1. Labeled data for the LSTM classification model, optionally with label gain.
+     "*_classification.tfrecords" (for both unidirectional and bidirectional
+     models).
+  2. Data for the unsupervised LM-LSTM model that predicts the next token.
+     "*_lm.tfrecords" (generates forward and reverse data).
+  3. Data for the unsupervised SA-LSTM model that uses Seq2Seq.
+     "*_sa.tfrecords".
+"""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import os
+import string
+
+import tensorflow as tf
+
+from adversarial_text.data import data_utils
+from adversarial_text.data import document_generators
+
+data = data_utils
+flags = tf.app.flags
+FLAGS = flags.FLAGS
+
+# Flags for input data are in document_generators.py
+flags.DEFINE_string('vocab_file', '', 'Path to the vocabulary file. Defaults '
+                    'to FLAGS.output_dir/vocab.txt.')
+flags.DEFINE_string('output_dir', '', 'Path to save tfrecords.')
+
+# Config
+flags.DEFINE_boolean('label_gain', False,
+                     'Enable linear label gain. If True, sentiment label will '
+                     'be included at each timestep with linear weight '
+                     'increase.')
+
+
+def build_shuffling_tf_record_writer(fname):
+  return data.ShufflingTFRecordWriter(os.path.join(FLAGS.output_dir, fname))
+
+
+def build_tf_record_writer(fname):
+  return tf.python_io.TFRecordWriter(os.path.join(FLAGS.output_dir, fname))
+
+
+def build_input_sequence(doc, vocab_ids):
+  """Builds input sequence from file.
+
+  Splits lines on whitespace. Treats punctuation as whitespace. For word-level
+  sequences, only keeps terms that are in the vocab.
+
+  Terms are added as token in the SequenceExample.  The EOS_TOKEN is also
+  appended. Label and weight features are set to 0.
+
+  Args:
+    doc: Document (defined in `document_generators`) from which to build the
+      sequence.
+    vocab_ids: dict<term, id>.
+
+  Returns:
+    SequenceExampleWrapper.
+  """
+  seq = data.SequenceWrapper()
+  for token in document_generators.tokens(doc):
+    if token in vocab_ids:
+      seq.add_timestep().set_token(vocab_ids[token])
+
+  # Add EOS token to end
+  seq.add_timestep().set_token(vocab_ids[data.EOS_TOKEN])
+
+  return seq
+
+
+def make_vocab_ids(vocab_filename):
+  if FLAGS.output_char:
+    ret = dict([(char, i) for i, char in enumerate(string.printable)])
+    ret[data.EOS_TOKEN] = len(string.printable)
+    return ret
+  else:
+    with open(vocab_filename) as vocab_f:
+      return dict([(line.strip(), i) for i, line in enumerate(vocab_f)])
+
+
+def generate_training_data(vocab_ids, writer_lm_all, writer_seq_ae_all):
+  """Generates training data."""
+
+  # Construct training data writers
+  writer_lm = build_shuffling_tf_record_writer(data.TRAIN_LM)
+  writer_seq_ae = build_shuffling_tf_record_writer(data.TRAIN_SA)
+  writer_class = build_shuffling_tf_record_writer(data.TRAIN_CLASS)
+  writer_valid_class = build_tf_record_writer(data.VALID_CLASS)
+  writer_rev_lm = build_shuffling_tf_record_writer(data.TRAIN_REV_LM)
+  writer_bd_class = build_shuffling_tf_record_writer(data.TRAIN_BD_CLASS)
+  writer_bd_valid_class = build_shuffling_tf_record_writer(data.VALID_BD_CLASS)
+
+  for doc in document_generators.documents(
+      dataset='train', include_unlabeled=True, include_validation=True):
+    input_seq = build_input_sequence(doc, vocab_ids)
+    if len(input_seq) < 2:
+      continue
+    rev_seq = data.build_reverse_sequence(input_seq)
+    lm_seq = data.build_lm_sequence(input_seq)
+    rev_lm_seq = data.build_lm_sequence(rev_seq)
+    seq_ae_seq = data.build_seq_ae_sequence(input_seq)
+    if doc.label is not None:
+      # Used for sentiment classification.
+      label_seq = data.build_labeled_sequence(
+          input_seq,
+          doc.label,
+          label_gain=(FLAGS.label_gain and not doc.is_validation))
+      bd_label_seq = data.build_labeled_sequence(
+          data.build_bidirectional_seq(input_seq, rev_seq),
+          doc.label,
+          label_gain=(FLAGS.label_gain and not doc.is_validation))
+      class_writer = writer_valid_class if doc.is_validation else writer_class
+      bd_class_writer = (writer_bd_valid_class
+                         if doc.is_validation else writer_bd_class)
+      class_writer.write(label_seq.seq.SerializeToString())
+      bd_class_writer.write(bd_label_seq.seq.SerializeToString())
+
+    # Write
+    lm_seq_ser = lm_seq.seq.SerializeToString()
+    seq_ae_seq_ser = seq_ae_seq.seq.SerializeToString()
+    writer_lm_all.write(lm_seq_ser)
+    writer_seq_ae_all.write(seq_ae_seq_ser)
+    if not doc.is_validation:
+      writer_lm.write(lm_seq_ser)
+      writer_rev_lm.write(rev_lm_seq.seq.SerializeToString())
+      writer_seq_ae.write(seq_ae_seq_ser)
+
+  # Close writers
+  writer_lm.close()
+  writer_seq_ae.close()
+  writer_class.close()
+  writer_valid_class.close()
+  writer_rev_lm.close()
+  writer_bd_class.close()
+  writer_bd_valid_class.close()
+
+
+def generate_test_data(vocab_ids, writer_lm_all, writer_seq_ae_all):
+  """Generates test data."""
+  # Construct test data writers
+  writer_lm = build_shuffling_tf_record_writer(data.TEST_LM)
+  writer_rev_lm = build_shuffling_tf_record_writer(data.TEST_REV_LM)
+  writer_seq_ae = build_shuffling_tf_record_writer(data.TEST_SA)
+  writer_class = build_tf_record_writer(data.TEST_CLASS)
+  writer_bd_class = build_shuffling_tf_record_writer(data.TEST_BD_CLASS)
+
+  for doc in document_generators.documents(
+      dataset='test', include_unlabeled=False, include_validation=True):
+    input_seq = build_input_sequence(doc, vocab_ids)
+    if len(input_seq) < 2:
+      continue
+    rev_seq = data.build_reverse_sequence(input_seq)
+    lm_seq = data.build_lm_sequence(input_seq)
+    rev_lm_seq = data.build_lm_sequence(rev_seq)
+    seq_ae_seq = data.build_seq_ae_sequence(input_seq)
+    label_seq = data.build_labeled_sequence(input_seq, doc.label)
+    bd_label_seq = data.build_labeled_sequence(
+        data.build_bidirectional_seq(input_seq, rev_seq), doc.label)
+
+    # Write
+    writer_class.write(label_seq.seq.SerializeToString())
+    writer_bd_class.write(bd_label_seq.seq.SerializeToString())
+    lm_seq_ser = lm_seq.seq.SerializeToString()
+    seq_ae_seq_ser = seq_ae_seq.seq.SerializeToString()
+    writer_lm.write(lm_seq_ser)
+    writer_rev_lm.write(rev_lm_seq.seq.SerializeToString())
+    writer_seq_ae.write(seq_ae_seq_ser)
+    writer_lm_all.write(lm_seq_ser)
+    writer_seq_ae_all.write(seq_ae_seq_ser)
+
+  # Close test writers
+  writer_lm.close()
+  writer_rev_lm.close()
+  writer_seq_ae.close()
+  writer_class.close()
+  writer_bd_class.close()
+
+
+def main(_):
+  tf.logging.info('Assigning vocabulary ids...')
+  vocab_ids = make_vocab_ids(
+      FLAGS.vocab_file or os.path.join(FLAGS.output_dir, 'vocab.txt'))
+
+  with build_shuffling_tf_record_writer(data.ALL_LM) as writer_lm_all:
+    with build_shuffling_tf_record_writer(data.ALL_SA) as writer_seq_ae_all:
+
+      tf.logging.info('Generating training data...')
+      generate_training_data(vocab_ids, writer_lm_all, writer_seq_ae_all)
+
+      tf.logging.info('Generating test data...')
+      generate_test_data(vocab_ids, writer_lm_all, writer_seq_ae_all)
+
+
+if __name__ == '__main__':
+  tf.app.run()

adversarial_text/data/gen_vocab.py

+# Copyright 2017 Google, Inc. 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.
+# ==============================================================================
+
+"""Generates vocabulary and term frequency files for datasets."""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+from collections import defaultdict
+
+import tensorflow as tf
+
+from adversarial_text.data import data_utils
+from adversarial_text.data import document_generators
+
+flags = tf.app.flags
+FLAGS = flags.FLAGS
+
+# Flags controlling input are in document_generators.py
+
+flags.DEFINE_string('output_dir', '',
+                    'Path to save vocab.txt and vocab_freq.txt.')
+
+flags.DEFINE_boolean('use_unlabeled', True, 'Whether to use the '
+                     'unlabeled sentiment dataset in the vocabulary.')
+flags.DEFINE_boolean('include_validation', False, 'Whether to include the '
+                     'validation set in the vocabulary.')
+flags.DEFINE_integer('doc_count_threshold', 1, 'The minimum number of '
+                     'documents a word or bigram should occur in to keep '
+                     'it in the vocabulary.')
+
+MAX_VOCAB_SIZE = 100 * 1000
+
+
+def fill_vocab_from_doc(doc, vocab_freqs, doc_counts):
+  """Fills vocabulary and doc counts with tokens from doc.
+
+  Args:
+    doc: Document to read tokens from.
+    vocab_freqs: dict<token, frequency count>
+    doc_counts: dict<token, document count>
+
+  Returns:
+    None
+  """
+  doc_seen = set()
+
+  for token in document_generators.tokens(doc):
+    if doc.add_tokens or token in vocab_freqs:
+      vocab_freqs[token] += 1
+    if token not in doc_seen:
+      doc_counts[token] += 1
+      doc_seen.add(token)
+
+
+def main(_):
+  vocab_freqs = defaultdict(int)
+  doc_counts = defaultdict(int)
+
+  # Fill vocabulary frequencies map and document counts map
+  for doc in document_generators.documents(
+      dataset='train',
+      include_unlabeled=FLAGS.use_unlabeled,
+      include_validation=FLAGS.include_validation):
+    fill_vocab_from_doc(doc, vocab_freqs, doc_counts)
+
+  # Filter out low-occurring terms
+  vocab_freqs = dict((term, freq) for term, freq in vocab_freqs.iteritems()
+                     if doc_counts[term] > FLAGS.doc_count_threshold)
+
+  # Sort by frequency
+  ordered_vocab_freqs = data_utils.sort_vocab_by_frequency(vocab_freqs)
+
+  # Limit vocab size
+  ordered_vocab_freqs = ordered_vocab_freqs[:MAX_VOCAB_SIZE]
+
+  # Add EOS token
+  ordered_vocab_freqs.append((data_utils.EOS_TOKEN, 1))
+
+  # Write
+  tf.gfile.MakeDirs(FLAGS.output_dir)
+  data_utils.write_vocab_and_frequency(ordered_vocab_freqs, FLAGS.output_dir)
+
+
+if __name__ == '__main__':
+  tf.app.run()

adversarial_text/evaluate.py

+# Copyright 2017 Google, Inc. 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 text classification model."""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import math
+import time
+
+import tensorflow as tf
+
+import graphs
+
+flags = tf.app.flags
+FLAGS = flags.FLAGS
+
+flags.DEFINE_string('master', '',
+                    'BNS name prefix of the Tensorflow eval master, '
+                    'or "local".')
+flags.DEFINE_string('eval_dir', '/tmp/text_eval',
+                    'Directory where to write event logs.')
+flags.DEFINE_string('eval_data', 'test', 'Specify which dataset is used. '
+                    '("train", "valid", "test") ')
+
+flags.DEFINE_string('checkpoint_dir', '/tmp/text_train',
+                    'Directory where to read model checkpoints.')
+flags.DEFINE_integer('eval_interval_secs', 60, 'How often to run the eval.')
+flags.DEFINE_integer('num_examples', 32, 'Number of examples to run.')
+flags.DEFINE_bool('run_once', False, 'Whether to run eval only once.')
+
+
+def restore_from_checkpoint(sess, saver):
+  """Restore model from checkpoint.
+
+  Args:
+    sess: Session.
+    saver: Saver for restoring the checkpoint.
+
+  Returns:
+    bool: Whether the checkpoint was found and restored
+  """
+  ckpt = tf.train.get_checkpoint_state(FLAGS.checkpoint_dir)
+  if not ckpt or not ckpt.model_checkpoint_path:
+    tf.logging.info('No checkpoint found at %s', FLAGS.checkpoint_dir)
+    return False
+
+  saver.restore(sess, ckpt.model_checkpoint_path)
+  return True
+
+
+def run_eval(eval_ops, summary_writer, saver):
+  """Runs evaluation over FLAGS.num_examples examples.
+
+  Args:
+    eval_ops: dict<metric name, tuple(value, update_op)>
+    summary_writer: Summary writer.
+    saver: Saver.
+
+  Returns:
+    dict<metric name, value>, with value being the average over all examples.
+  """
+  sv = tf.train.Supervisor(logdir=FLAGS.eval_dir, saver=None, summary_op=None)
+  with sv.managed_session(
+      master=FLAGS.master, start_standard_services=False) as sess:
+    if not restore_from_checkpoint(sess, saver):
+      return
+    sv.start_queue_runners(sess)
+
+    metric_names, ops = zip(*eval_ops.items())
+    value_ops, update_ops = zip(*ops)
+
+    # Run update ops
+    num_batches = int(math.ceil(FLAGS.num_examples / FLAGS.batch_size))
+    tf.logging.info('Running %d batches for evaluation.', num_batches)
+    for i in range(num_batches):
+      if (i + 1) % 10 == 0:
+        tf.logging.info('Running batch %d/%d...', i + 1, num_batches)
+      sess.run(update_ops)
+
+    values = sess.run(value_ops)
+    metric_values = dict(zip(metric_names, values))
+
+    tf.logging.info('Eval metric values:')
+    summary = tf.summary.Summary()
+    for name, val in metric_values.items():
+      summary.value.add(tag=name, simple_value=val)
+      tf.logging.info('%s = %.3f', name, val)
+
+    global_step_val = sess.run(tf.train.get_global_step())
+    summary_writer.add_summary(summary, global_step_val)
+
+    return metric_values
+
+
+def main(_):
+  tf.logging.set_verbosity(tf.logging.INFO)
+  tf.gfile.MakeDirs(FLAGS.eval_dir)
+  tf.logging.info('Building eval graph...')
+  output = graphs.get_model().eval_graph(FLAGS.eval_data)
+  eval_ops, moving_averaged_variables = output
+
+  saver = tf.train.Saver(moving_averaged_variables)
+  summary_writer = tf.summary.FileWriter(
+      FLAGS.eval_dir, graph=tf.get_default_graph())
+
+  while True:
+    run_eval(eval_ops, summary_writer, saver)
+    if FLAGS.run_once:
+      break
+    time.sleep(FLAGS.eval_interval_secs)
+
+
+if __name__ == '__main__':
+  tf.app.run()

adversarial_text/graphs.py

+# Copyright 2017 Google, Inc. 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.
+# ==============================================================================
+
+"""Virtual adversarial text models."""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import csv
+import os
+import tensorflow as tf
+
+import adversarial_losses as adv_lib
+import inputs as inputs_lib
+import layers as layers_lib
+
+flags = tf.app.flags
+FLAGS = flags.FLAGS
+
+# Flags governing adversarial training are defined in adversarial_losses.py.
+
+# Classifier
+flags.DEFINE_integer('num_classes', 2, 'Number of classes for classification')
+
+# Data path
+flags.DEFINE_string('data_dir', '/tmp/IMDB',
+                    'Directory path to preprocessed text dataset.')
+flags.DEFINE_string('vocab_freq_path', None,
+                    'Path to pre-calculated vocab frequency data. If '
+                    'None, use FLAGS.data_dir/vocab_freq.txt.')
+flags.DEFINE_integer('batch_size', 64, 'Size of the batch.')
+flags.DEFINE_integer('num_timesteps', 100, 'Number of timesteps for BPTT')
+
+# Model architechture
+flags.DEFINE_bool('bidir_lstm', False, 'Whether to build a bidirectional LSTM.')
+flags.DEFINE_integer('rnn_num_layers', 1, 'Number of LSTM layers.')
+flags.DEFINE_integer('rnn_cell_size', 512,
+                     'Number of hidden units in the LSTM.')
+flags.DEFINE_integer('cl_num_layers', 1,
+                     'Number of hidden layers of classification model.')
+flags.DEFINE_integer('cl_hidden_size', 30,
+                     'Number of hidden units in classification layer.')
+flags.DEFINE_integer('num_candidate_samples', -1,
+                     'Num samples used in the sampled output layer.')
+flags.DEFINE_bool('use_seq2seq_autoencoder', False,
+                  'If True, seq2seq auto-encoder is used to pretrain. '
+                  'If False, standard language model is used.')
+
+# Vocabulary and embeddings
+flags.DEFINE_integer('embedding_dims', 256, 'Dimensions of embedded vector.')
+flags.DEFINE_integer('vocab_size', 86934,
+                     'The size of the vocaburary. This value '
+                     'should be exactly same as the number of the '
+                     'vocabulary used in dataset. Because the last '
+                     'indexed vocabulary of the dataset preprocessed by '
+                     'my preprocessed code, is always <eos> and here we '
+                     'specify the <eos> with the the index.')
+flags.DEFINE_bool('normalize_embeddings', True,
+                  'Normalize word embeddings by vocab frequency')
+
+# Optimization
+flags.DEFINE_float('learning_rate', 0.001, 'Learning rate while fine-tuning.')
+flags.DEFINE_float('learning_rate_decay_factor', 1.0,
+                   'Learning rate decay factor')
+flags.DEFINE_boolean('sync_replicas', False, 'sync_replica or not')
+flags.DEFINE_integer('replicas_to_aggregate', 1,
+                     'The number of replicas to aggregate')
+
+# Regularization
+flags.DEFINE_float('max_grad_norm', 1.0,
+                   'Clip the global gradient norm to this value.')
+flags.DEFINE_float('keep_prob_emb', 1.0, 'keep probability on embedding layer')
+flags.DEFINE_float('keep_prob_lstm_out', 1.0,
+                   'keep probability on lstm output.')
+flags.DEFINE_float('keep_prob_cl_hidden', 1.0,
+                   'keep probability on classification hidden layer')
+
+
+def get_model():
+  if FLAGS.bidir_lstm:
+    return VatxtBidirModel()
+  else:
+    return VatxtModel()
+
+
+class VatxtModel(object):
+  """Constructs training and evaluation graphs.
+
+  Main methods: `classifier_training()`, `language_model_training()`,
+  and `eval_graph()`.
+
+  Variable reuse is a critical part of the model, both for sharing variables
+  between the language model and the classifier, and for reusing variables for
+  the adversarial loss calculation. To ensure correct variable reuse, all
+  variables are created in Keras-style layers, wherein stateful layers (i.e.
+  layers with variables) are represented as callable instances of the Layer
+  class. Each time the Layer instance is called, it is using the same variables.
+
+  All Layers are constructed in the __init__ method and reused in the various
+  graph-building functions.
+  """
+
+  def __init__(self, cl_logits_input_dim=None):
+    self.global_step = tf.contrib.framework.get_or_create_global_step()
+    self.vocab_freqs = _get_vocab_freqs()
+
+    # Cache VatxtInput objects
+    self.cl_inputs = None
+    self.lm_inputs = None
+
+    # Cache intermediate Tensors that are reused
+    self.tensors = {}
+
+    # Construct layers which are reused in constructing the LM and
+    # Classification graphs. Instantiating them all once here ensures that
+    # variable reuse works correctly.
+    self.layers = {}
+    self.layers['embedding'] = layers_lib.Embedding(
+        FLAGS.vocab_size, FLAGS.embedding_dims, FLAGS.normalize_embeddings,
+        self.vocab_freqs, FLAGS.keep_prob_emb)
+    self.layers['lstm'] = layers_lib.LSTM(
+        FLAGS.rnn_cell_size, FLAGS.rnn_num_layers, FLAGS.keep_prob_lstm_out)
+    self.layers['lm_loss'] = layers_lib.SoftmaxLoss(
+        FLAGS.vocab_size,
+        FLAGS.num_candidate_samples,
+        self.vocab_freqs,
+        name='LM_loss')
+
+    cl_logits_input_dim = cl_logits_input_dim or FLAGS.rnn_cell_size
+    self.layers['cl_logits'] = layers_lib.cl_logits_subgraph(
+        [FLAGS.cl_hidden_size] * FLAGS.cl_num_layers, cl_logits_input_dim,
+        FLAGS.num_classes, FLAGS.keep_prob_cl_hidden)
+
+  @property
+  def pretrained_variables(self):
+    return (self.layers['embedding'].trainable_weights +
+            self.layers['lstm'].trainable_weights)
+
+  def classifier_training(self):
+    loss = self.classifier_graph()
+    train_op = optimize(loss, self.global_step)
+    return train_op, loss, self.global_step
+
+  def language_model_training(self):
+    loss = self.language_model_graph()
+    train_op = optimize(loss, self.global_step)
+    return train_op, loss, self.global_step
+
+  def classifier_graph(self):
+    """Constructs classifier graph from inputs to classifier loss.
+
+    * Caches the VatxtInput object in `self.cl_inputs`
+    * Caches tensors: `cl_embedded`, `cl_logits`, `cl_loss`
+
+    Returns:
+      loss: scalar float.
+    """
+    inputs = _inputs('train', pretrain=False)
+    self.cl_inputs = inputs
+    embedded = self.layers['embedding'](inputs.tokens)
+    self.tensors['cl_embedded'] = embedded
+
+    _, next_state, logits, loss = self.cl_loss_from_embedding(
+        embedded, return_intermediates=True)
+    tf.summary.scalar('classification_loss', loss)
+    self.tensors['cl_logits'] = logits
+    self.tensors['cl_loss'] = loss
+
+    acc = layers_lib.accuracy(logits, inputs.labels, inputs.weights)
+    tf.summary.scalar('accuracy', acc)
+
+    adv_loss = (self.adversarial_loss() * tf.constant(
+        FLAGS.adv_reg_coeff, name='adv_reg_coeff'))
+    tf.summary.scalar('adversarial_loss', adv_loss)
+
+    total_loss = loss + adv_loss
+    tf.summary.scalar('total_classification_loss', total_loss)
+
+    with tf.control_dependencies([inputs.save_state(next_state)]):
+      total_loss = tf.identity(total_loss)
+
+    return total_loss
+
+  def language_model_graph(self, compute_loss=True):
+    """Constructs LM graph from inputs to LM loss.
+
+    * Caches the VatxtInput object in `self.lm_inputs`
+    * Caches tensors: `lm_embedded`
+
+    Args:
+      compute_loss: bool, whether to compute and return the loss or stop after
+        the LSTM computation.
+
+    Returns:
+      loss: scalar float.
+    """
+    inputs = _inputs('train', pretrain=True)
+    self.lm_inputs = inputs
+    return self._lm_loss(inputs, compute_loss=compute_loss)
+
+  def _lm_loss(self,
+               inputs,
+               emb_key='lm_embedded',
+               lstm_layer='lstm',
+               lm_loss_layer='lm_loss',
+               loss_name='lm_loss',
+               compute_loss=True):
+    embedded = self.layers['embedding'](inputs.tokens)
+    self.tensors[emb_key] = embedded
+    lstm_out, next_state = self.layers[lstm_layer](embedded, inputs.state,
+                                                   inputs.length)
+    if compute_loss:
+      loss = self.layers[lm_loss_layer](
+          [lstm_out, inputs.labels, inputs.weights])
+      with tf.control_dependencies([inputs.save_state(next_state)]):
+        loss = tf.identity(loss)
+        tf.summary.scalar(loss_name, loss)
+
+      return loss
+
+  def eval_graph(self, dataset='test'):
+    """Constructs classifier evaluation graph.
+
+    Args:
+      dataset: the labeled dataset to evaluate, {'train', 'test', 'valid'}.
+
+    Returns:
+      eval_ops: dict<metric name, tuple(value, update_op)>
+      var_restore_dict: dict mapping variable restoration names to variables.
+        Trainable variables will be mapped to their moving average names.
+    """
+    inputs = _inputs(dataset, pretrain=False)
+    embedded = self.layers['embedding'](inputs.tokens)
+    _, next_state, logits, _ = self.cl_loss_from_embedding(
+        embedded, inputs=inputs, return_intermediates=True)
+
+    eval_ops = {
+        'accuracy':
+            tf.contrib.metrics.streaming_accuracy(
+                layers_lib.predictions(logits), inputs.labels,
+                inputs.weights)
+    }
+
+    with tf.control_dependencies([inputs.save_state(next_state)]):
+      acc, acc_update = eval_ops['accuracy']
+      acc_update = tf.identity(acc_update)
+      eval_ops['accuracy'] = (acc, acc_update)
+
+    var_restore_dict = make_restore_average_vars_dict()
+    return eval_ops, var_restore_dict
+
+  def cl_loss_from_embedding(self,
+                             embedded,
+                             inputs=None,
+                             return_intermediates=False):
+    """Compute classification loss from embedding.
+
+    Args:
+      embedded: 3-D float Tensor [batch_size, num_timesteps, embedding_dim]
+      inputs: VatxtInput, defaults to self.cl_inputs.
+      return_intermediates: bool, whether to return intermediate tensors or only
+        the final loss.
+
+    Returns:
+      If return_intermediates is True:
+        lstm_out, next_state, logits, loss
+      Else:
+        loss
+    """
+    if inputs is None:
+      inputs = self.cl_inputs
+
+    lstm_out, next_state = self.layers['lstm'](embedded, inputs.state,
+                                               inputs.length)
+    logits = self.layers['cl_logits'](lstm_out)
+    loss = layers_lib.classification_loss(logits, inputs.labels, inputs.weights)
+
+    if return_intermediates:
+      return lstm_out, next_state, logits, loss
+    else:
+      return loss
+
+  def adversarial_loss(self):
+    """Compute adversarial loss based on FLAGS.adv_training_method."""
+
+    def random_perturbation_loss():
+      return adv_lib.random_perturbation_loss(self.tensors['cl_embedded'],
+                                              self.cl_inputs.length,
+                                              self.cl_loss_from_embedding)
+
+    def adversarial_loss():
+      return adv_lib.adversarial_loss(self.tensors['cl_embedded'],
+                                      self.tensors['cl_loss'],
+                                      self.cl_loss_from_embedding)
+
+    def virtual_adversarial_loss():
+      """Computes virtual adversarial loss.
+
+      Uses lm_inputs and constructs the language model graph if it hasn't yet
+      been constructed.
+
+      Also ensures that the LM input states are saved for LSTM state-saving
+      BPTT.
+
+      Returns:
+        loss: float scalar.
+      """
+      if self.lm_inputs is None:
+        self.language_model_graph(compute_loss=False)
+
+      def logits_from_embedding(embedded, return_next_state=False):
+        _, next_state, logits, _ = self.cl_loss_from_embedding(
+            embedded, inputs=self.lm_inputs, return_intermediates=True)
+        if return_next_state:
+          return next_state, logits
+        else:
+          return logits
+
+      next_state, lm_cl_logits = logits_from_embedding(
+          self.tensors['lm_embedded'], return_next_state=True)
+
+      va_loss = adv_lib.virtual_adversarial_loss(
+          lm_cl_logits, self.tensors['lm_embedded'], self.lm_inputs,
+          logits_from_embedding)
+
+      with tf.control_dependencies([self.lm_inputs.save_state(next_state)]):
+        va_loss = tf.identity(va_loss)
+
+      return va_loss
+
+    def combo_loss():
+      return adversarial_loss() + virtual_adversarial_loss()
+
+    adv_training_methods = {
+        # Random perturbation
+        'rp': random_perturbation_loss,
+        # Adversarial training
+        'at': adversarial_loss,
+        # Virtual adversarial training
+        'vat': virtual_adversarial_loss,
+        # Both at and vat
+        'atvat': combo_loss,
+        '': lambda: tf.constant(0.),
+        None: lambda: tf.constant(0.),
+    }
+
+    with tf.name_scope('adversarial_loss'):
+      return adv_training_methods[FLAGS.adv_training_method]()
+
+
+class VatxtBidirModel(VatxtModel):
+  """Extension of VatxtModel that supports bidirectional input."""
+
+  def __init__(self):
+    super(VatxtBidirModel,
+          self).__init__(cl_logits_input_dim=FLAGS.rnn_cell_size * 2)
+
+    # Reverse LSTM and LM loss for bidirectional models
+    self.layers['lstm_reverse'] = layers_lib.LSTM(
+        FLAGS.rnn_cell_size,
+        FLAGS.rnn_num_layers,
+        FLAGS.keep_prob_lstm_out,
+        name='LSTM_Reverse')
+    self.layers['lm_loss_reverse'] = layers_lib.SoftmaxLoss(
+        FLAGS.vocab_size,
+        FLAGS.num_candidate_samples,
+        self.vocab_freqs,
+        name='LM_loss_reverse')
+
+  @property
+  def pretrained_variables(self):
+    variables = super(VatxtBidirModel, self).pretrained_variables
+    variables.extend(self.layers['lstm_reverse'].trainable_weights)
+    return variables
+
+  def classifier_graph(self):
+    """Constructs classifier graph from inputs to classifier loss.
+
+    * Caches the VatxtInput objects in `self.cl_inputs`
+    * Caches tensors: `cl_embedded` (tuple of forward and reverse), `cl_logits`,
+      `cl_loss`
+
+    Returns:
+      loss: scalar float.
+    """
+    inputs = _inputs('train', pretrain=False, bidir=True)
+    self.cl_inputs = inputs
+    f_inputs, _ = inputs
+
+    # Embed both forward and reverse with a shared embedding
+    embedded = [self.layers['embedding'](inp.tokens) for inp in inputs]
+    self.tensors['cl_embedded'] = embedded
+
+    _, next_states, logits, loss = self.cl_loss_from_embedding(
+        embedded, return_intermediates=True)
+    tf.summary.scalar('classification_loss', loss)
+    self.tensors['cl_logits'] = logits
+    self.tensors['cl_loss'] = loss
+
+    acc = layers_lib.accuracy(logits, f_inputs.labels, f_inputs.weights)
+    tf.summary.scalar('accuracy', acc)
+
+    adv_loss = (self.adversarial_loss() * tf.constant(
+        FLAGS.adv_reg_coeff, name='adv_reg_coeff'))
+    tf.summary.scalar('adversarial_loss', adv_loss)
+
+    total_loss = loss + adv_loss
+    tf.summary.scalar('total_classification_loss', total_loss)
+
+    saves = [inp.save_state(state) for (inp, state) in zip(inputs, next_states)]
+    with tf.control_dependencies(saves):
+      total_loss = tf.identity(total_loss)
+
+    return total_loss
+
+  def language_model_graph(self, compute_loss=True):
+    """Constructs forward and reverse LM graphs from inputs to LM losses.
+
+    * Caches the VatxtInput objects in `self.lm_inputs`
+    * Caches tensors: `lm_embedded`, `lm_embedded_reverse`
+
+    Args:
+      compute_loss: bool, whether to compute and return the loss or stop after
+        the LSTM computation.
+
+    Returns:
+      loss: scalar float, sum of forward and reverse losses.
+    """
+    inputs = _inputs('train', pretrain=True, bidir=True)
+    self.lm_inputs = inputs
+    f_inputs, r_inputs = inputs
+    f_loss = self._lm_loss(f_inputs, compute_loss=compute_loss)
+    r_loss = self._lm_loss(
+        r_inputs,
+        emb_key='lm_embedded_reverse',
+        lstm_layer='lstm_reverse',
+        lm_loss_layer='lm_loss_reverse',
+        loss_name='lm_loss_reverse',
+        compute_loss=compute_loss)
+    if compute_loss:
+      return f_loss + r_loss
+
+  def eval_graph(self, dataset='test'):
+    """Constructs classifier evaluation graph.
+
+    Args:
+      dataset: the labeled dataset to evaluate, {'train', 'test', 'valid'}.
+
+    Returns:
+      eval_ops: dict<metric name, tuple(value, update_op)>
+      var_restore_dict: dict mapping variable restoration names to variables.
+        Trainable variables will be mapped to their moving average names.
+    """
+    inputs = _inputs(dataset, pretrain=False, bidir=True)
+    embedded = [self.layers['embedding'](inp.tokens) for inp in inputs]
+    _, next_states, logits, _ = self.cl_loss_from_embedding(
+        embedded, inputs=inputs, return_intermediates=True)
+    f_inputs, _ = inputs
+
+    eval_ops = {
+        'accuracy':
+            tf.contrib.metrics.streaming_accuracy(
+                layers_lib.predictions(logits), f_inputs.labels,
+                f_inputs.weights)
+    }
+
+    # Save states on accuracy update
+    saves = [inp.save_state(state) for (inp, state) in zip(inputs, next_states)]
+    with tf.control_dependencies(saves):
+      acc, acc_update = eval_ops['accuracy']
+      acc_update = tf.identity(acc_update)
+      eval_ops['accuracy'] = (acc, acc_update)
+
+    var_restore_dict = make_restore_average_vars_dict()
+    return eval_ops, var_restore_dict
+
+  def cl_loss_from_embedding(self,
+                             embedded,
+                             inputs=None,
+                             return_intermediates=False):
+    """Compute classification loss from embedding.
+
+    Args:
+      embedded: Length 2 tuple of 3-D float Tensor
+        [batch_size, num_timesteps, embedding_dim].
+      inputs: Length 2 tuple of VatxtInput, defaults to self.cl_inputs.
+      return_intermediates: bool, whether to return intermediate tensors or only
+        the final loss.
+
+    Returns:
+      If return_intermediates is True:
+        lstm_out, next_states, logits, loss
+      Else:
+        loss
+    """
+    if inputs is None:
+      inputs = self.cl_inputs
+
+    out = []
+    for (layer_name, emb, inp) in zip(['lstm', 'lstm_reverse'], embedded,
+                                      inputs):
+      out.append(self.layers[layer_name](emb, inp.state, inp.length))
+    lstm_outs, next_states = zip(*out)
+
+    # Concatenate output of forward and reverse LSTMs
+    lstm_out = tf.concat(lstm_outs, 1)
+
+    logits = self.layers['cl_logits'](lstm_out)
+    f_inputs, _ = inputs  # pylint: disable=unpacking-non-sequence
+    loss = layers_lib.classification_loss(logits, f_inputs.labels,
+                                          f_inputs.weights)
+
+    if return_intermediates:
+      return lstm_out, next_states, logits, loss
+    else:
+      return loss
+
+  def adversarial_loss(self):
+    """Compute adversarial loss based on FLAGS.adv_training_method."""
+
+    def random_perturbation_loss():
+      return adv_lib.random_perturbation_loss_bidir(self.tensors['cl_embedded'],
+                                                    self.cl_inputs[0].length,
+                                                    self.cl_loss_from_embedding)
+
+    def adversarial_loss():
+      return adv_lib.adversarial_loss_bidir(self.tensors['cl_embedded'],
+                                            self.tensors['cl_loss'],
+                                            self.cl_loss_from_embedding)
+
+    def virtual_adversarial_loss():
+      """Computes virtual adversarial loss.
+
+      Uses lm_inputs and constructs the language model graph if it hasn't yet
+      been constructed.
+
+      Also ensures that the LM input states are saved for LSTM state-saving
+      BPTT.
+
+      Returns:
+        loss: float scalar.
+      """
+      if self.lm_inputs is None:
+        self.language_model_graph(compute_loss=False)
+
+      def logits_from_embedding(embedded, return_next_state=False):
+        _, next_states, logits, _ = self.cl_loss_from_embedding(
+            embedded, inputs=self.lm_inputs, return_intermediates=True)
+        if return_next_state:
+          return next_states, logits
+        else:
+          return logits
+
+      lm_embedded = (self.tensors['lm_embedded'],
+                     self.tensors['lm_embedded_reverse'])
+      next_states, lm_cl_logits = logits_from_embedding(
+          lm_embedded, return_next_state=True)
+
+      va_loss = adv_lib.virtual_adversarial_loss_bidir(
+          lm_cl_logits, lm_embedded, self.lm_inputs, logits_from_embedding)
+
+      saves = [
+          inp.save_state(state)
+          for (inp, state) in zip(self.lm_inputs, next_states)
+      ]
+      with tf.control_dependencies(saves):
+        va_loss = tf.identity(va_loss)
+
+      return va_loss
+
+    def combo_loss():
+      return adversarial_loss() + virtual_adversarial_loss()
+
+    adv_training_methods = {
+        # Random perturbation
+        'rp': random_perturbation_loss,
+        # Adversarial training
+        'at': adversarial_loss,
+        # Virtual adversarial training
+        'vat': virtual_adversarial_loss,
+        # Both at and vat
+        'atvat': combo_loss,
+        '': lambda: tf.constant(0.),
+        None: lambda: tf.constant(0.),
+    }
+
+    with tf.name_scope('adversarial_loss'):
+      return adv_training_methods[FLAGS.adv_training_method]()
+
+
+def _inputs(dataset='train', pretrain=False, bidir=False):
+  return inputs_lib.inputs(
+      data_dir=FLAGS.data_dir,
+      phase=dataset,
+      bidir=bidir,
+      pretrain=pretrain,
+      use_seq2seq=pretrain and FLAGS.use_seq2seq_autoencoder,
+      state_size=FLAGS.rnn_cell_size,
+      num_layers=FLAGS.rnn_num_layers,
+      batch_size=FLAGS.batch_size,
+      unroll_steps=FLAGS.num_timesteps)
+
+
+def _get_vocab_freqs():
+  """Returns vocab frequencies.
+
+  Returns:
+    List of integers, length=FLAGS.vocab_size.
+
+  Raises:
+    ValueError: if the length of the frequency file is not equal to the vocab
+      size, or if the file is not found.
+  """
+  path = FLAGS.vocab_freq_path or os.path.join(FLAGS.data_dir, 'vocab_freq.txt')
+
+  if tf.gfile.Exists(path):
+    with tf.gfile.Open(path) as f:
+      # Get pre-calculated frequencies of words.
+      reader = csv.reader(f, quoting=csv.QUOTE_NONE)
+      freqs = [int(row[-1]) for row in reader]
+      if len(freqs) != FLAGS.vocab_size:
+        raise ValueError('Frequency file length %d != vocab size %d' %
+                         (len(freqs), FLAGS.vocab_size))
+  else:
+    if FLAGS.vocab_freq_path:
+      raise ValueError('vocab_freq_path not found')
+    freqs = [1] * FLAGS.vocab_size
+
+  return freqs
+
+
+def make_restore_average_vars_dict():
+  """Returns dict mapping moving average names to variables."""
+  var_restore_dict = {}
+  variable_averages = tf.train.ExponentialMovingAverage(0.999)
+  for v in tf.global_variables():
+    if v in tf.trainable_variables():
+      name = variable_averages.average_name(v)
+    else:
+      name = v.op.name
+    var_restore_dict[name] = v
+  return var_restore_dict
+
+
+def optimize(loss, global_step):
+  return layers_lib.optimize(
+      loss, global_step, FLAGS.max_grad_norm, FLAGS.learning_rate,
+      FLAGS.learning_rate_decay_factor, FLAGS.sync_replicas,
+      FLAGS.replicas_to_aggregate, FLAGS.task)

adversarial_text/graphs_test.py

+# Copyright 2017 Google, Inc. 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 graphs."""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+from collections import defaultdict
+import operator
+import os
+import random
+import shutil
+import string
+import tempfile
+
+import tensorflow as tf
+
+import graphs
+from adversarial_text.data import data_utils
+
+flags = tf.app.flags
+FLAGS = flags.FLAGS
+data = data_utils
+
+flags.DEFINE_integer('task', 0, 'Task id; needed for SyncReplicas test')
+
+
+def _build_random_vocabulary(vocab_size=100):
+  """Builds and returns a dict<term, id>."""
+  vocab = set()
+  while len(vocab) < (vocab_size - 1):
+    rand_word = ''.join(
+        random.choice(string.ascii_lowercase)
+        for _ in range(random.randint(1, 10)))
+    vocab.add(rand_word)
+
+  vocab_ids = dict([(word, i) for i, word in enumerate(vocab)])
+  vocab_ids[data.EOS_TOKEN] = vocab_size - 1
+  return vocab_ids
+
+
+def _build_random_sequence(vocab_ids):
+  seq_len = random.randint(10, 200)
+  ids = vocab_ids.values()
+  seq = data.SequenceWrapper()
+  for token_id in [random.choice(ids) for _ in range(seq_len)]:
+    seq.add_timestep().set_token(token_id)
+  return seq
+
+
+def _build_vocab_frequencies(seqs, vocab_ids):
+  vocab_freqs = defaultdict(int)
+  ids_to_words = dict([(i, word) for word, i in vocab_ids.iteritems()])
+  for seq in seqs:
+    for timestep in seq:
+      vocab_freqs[ids_to_words[timestep.token]] += 1
+
+  vocab_freqs[data.EOS_TOKEN] = 0
+  return vocab_freqs
+
+
+class GraphsTest(tf.test.TestCase):
+  """Test graph construction methods."""
+
+  @classmethod
+  def setUpClass(cls):
+    # Make model small
+    FLAGS.batch_size = 2
+    FLAGS.num_timesteps = 3
+    FLAGS.embedding_dims = 4
+    FLAGS.rnn_num_layers = 2
+    FLAGS.rnn_cell_size = 4
+    FLAGS.cl_num_layers = 2
+    FLAGS.cl_hidden_size = 4
+    FLAGS.vocab_size = 10
+
+    # Set input/output flags
+    FLAGS.data_dir = tempfile.mkdtemp()
+
+    # Build and write sequence files.
+    vocab_ids = _build_random_vocabulary(FLAGS.vocab_size)
+    seqs = [_build_random_sequence(vocab_ids) for _ in range(5)]
+    seqs_label = [
+        data.build_labeled_sequence(seq, random.choice([True, False]))
+        for seq in seqs
+    ]
+    seqs_lm = [data.build_lm_sequence(seq) for seq in seqs]
+    seqs_ae = [data.build_seq_ae_sequence(seq) for seq in seqs]
+    seqs_rev = [data.build_reverse_sequence(seq) for seq in seqs]
+    seqs_bidir = [
+        data.build_bidirectional_seq(seq, rev)
+        for seq, rev in zip(seqs, seqs_rev)
+    ]
+    seqs_bidir_label = [
+        data.build_labeled_sequence(bd_seq, random.choice([True, False]))
+        for bd_seq in seqs_bidir
+    ]
+
+    filenames = [
+        data.TRAIN_CLASS, data.TRAIN_LM, data.TRAIN_SA, data.TEST_CLASS,
+        data.TRAIN_REV_LM, data.TRAIN_BD_CLASS, data.TEST_BD_CLASS
+    ]
+    seq_lists = [
+        seqs_label, seqs_lm, seqs_ae, seqs_label, seqs_rev, seqs_bidir,
+        seqs_bidir_label
+    ]
+    for fname, seq_list in zip(filenames, seq_lists):
+      with tf.python_io.TFRecordWriter(
+          os.path.join(FLAGS.data_dir, fname)) as writer:
+        for seq in seq_list:
+          writer.write(seq.seq.SerializeToString())
+
+    # Write vocab.txt and vocab_freq.txt
+    vocab_freqs = _build_vocab_frequencies(seqs, vocab_ids)
+    ordered_vocab_freqs = sorted(
+        vocab_freqs.items(), key=operator.itemgetter(1), reverse=True)
+    with open(os.path.join(FLAGS.data_dir, 'vocab.txt'), 'w') as vocab_f:
+      with open(os.path.join(FLAGS.data_dir, 'vocab_freq.txt'), 'w') as freq_f:
+        for word, freq in ordered_vocab_freqs:
+          vocab_f.write('{}\n'.format(word))
+          freq_f.write('{}\n'.format(freq))
+
+  @classmethod
+  def tearDownClass(cls):
+    shutil.rmtree(FLAGS.data_dir)
+
+  def setUp(self):
+    # Reset FLAGS
+    FLAGS.rnn_num_layers = 1
+    FLAGS.sync_replicas = False
+    FLAGS.adv_training_method = None
+    FLAGS.num_candidate_samples = -1
+    FLAGS.num_classes = 2
+    FLAGS.use_seq2seq_autoencoder = False
+
+    # Reset Graph
+    tf.reset_default_graph()
+
+  def testClassifierGraph(self):
+    FLAGS.rnn_num_layers = 2
+    model = graphs.VatxtModel()
+    train_op, _, _ = model.classifier_training()
+    # Pretrained vars: embedding + LSTM layers
+    self.assertEqual(
+        len(model.pretrained_variables), 1 + 2 * FLAGS.rnn_num_layers)
+    with self.test_session() as sess:
+      sess.run(tf.global_variables_initializer())
+      tf.train.start_queue_runners(sess)
+      sess.run(train_op)
+
+  def testLanguageModelGraph(self):
+    train_op, _, _ = graphs.VatxtModel().language_model_training()
+    with self.test_session() as sess:
+      sess.run(tf.global_variables_initializer())
+      tf.train.start_queue_runners(sess)
+      sess.run(train_op)
+
+  def testMulticlass(self):
+    FLAGS.num_classes = 10
+    graphs.VatxtModel().classifier_graph()
+
+  def testATMethods(self):
+    at_methods = [None, 'rp', 'at', 'vat', 'atvat']
+    for method in at_methods:
+      FLAGS.adv_training_method = method
+      with tf.Graph().as_default():
+        graphs.VatxtModel().classifier_graph()
+
+        # Ensure variables have been reused
+        # Embedding + LSTM layers + hidden layers + logits layer
+        expected_num_vars = 1 + 2 * FLAGS.rnn_num_layers + 2 * (
+            FLAGS.cl_num_layers) + 2
+        self.assertEqual(len(tf.trainable_variables()), expected_num_vars)
+
+  def testSyncReplicas(self):
+    FLAGS.sync_replicas = True
+    graphs.VatxtModel().language_model_training()
+
+  def testCandidateSampling(self):
+    FLAGS.num_candidate_samples = 10
+    graphs.VatxtModel().language_model_training()
+
+  def testSeqAE(self):
+    FLAGS.use_seq2seq_autoencoder = True
+    graphs.VatxtModel().language_model_training()
+
+  def testBidirLM(self):
+    graphs.VatxtBidirModel().language_model_graph()
+
+  def testBidirClassifier(self):
+    at_methods = [None, 'rp', 'at', 'vat', 'atvat']
+    for method in at_methods:
+      FLAGS.adv_training_method = method
+      with tf.Graph().as_default():
+        graphs.VatxtBidirModel().classifier_graph()
+
+        # Ensure variables have been reused
+        # Embedding + 2 LSTM layers + hidden layers + logits layer
+        expected_num_vars = 1 + 2 * 2 * FLAGS.rnn_num_layers + 2 * (
+            FLAGS.cl_num_layers) + 2
+        self.assertEqual(len(tf.trainable_variables()), expected_num_vars)
+
+  def testEvalGraph(self):
+    _, _ = graphs.VatxtModel().eval_graph()
+
+  def testBidirEvalGraph(self):
+    _, _ = graphs.VatxtBidirModel().eval_graph()
+
+
+if __name__ == '__main__':
+  tf.test.main()

adversarial_text/inputs.py

+# Copyright 2017 Google, Inc. 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.
+# ==============================================================================
+
+"""Input utils for virtual adversarial text classification."""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import os
+import tensorflow as tf
+
+from adversarial_text.data import data_utils
+
+
+class VatxtInput(object):
+  """Wrapper around NextQueuedSequenceBatch."""
+
+  def __init__(self, batch, state_name=None, tokens=None, num_states=0):
+    """Construct VatxtInput.
+
+    Args:
+      batch: NextQueuedSequenceBatch.
+      state_name: str, name of state to fetch and save.
+      tokens: int Tensor, tokens. Defaults to batch's F_TOKEN_ID sequence.
+      num_states: int The number of states to store.
+    """
+    self._batch = batch
+    self._state_name = state_name
+    self._tokens = (tokens if tokens is not None else
+                    batch.sequences[data_utils.SequenceWrapper.F_TOKEN_ID])
+    self._num_states = num_states
+
+    # Once the tokens have passed through embedding and LSTM, the output Tensor
+    # shapes will be time-major, i.e. shape = (time, batch, dim). Here we make
+    # both weights and labels time-major with a transpose, and then merge the
+    # time and batch dimensions such that they are both vectors of shape
+    # (time*batch).
+    w = batch.sequences[data_utils.SequenceWrapper.F_WEIGHT]
+    w = tf.transpose(w, [1, 0])
+    w = tf.reshape(w, [-1])
+    self._weights = w
+
+    l = batch.sequences[data_utils.SequenceWrapper.F_LABEL]
+    l = tf.transpose(l, [1, 0])
+    l = tf.reshape(l, [-1])
+    self._labels = l
+
+  @property
+  def tokens(self):
+    return self._tokens
+
+  @property
+  def weights(self):
+    return self._weights
+
+  @property
+  def labels(self):
+    return self._labels
+
+  @property
+  def length(self):
+    return self._batch.length
+
+  @property
+  def state_name(self):
+    return self._state_name
+
+  @property
+  def state(self):
+    # LSTM tuple states
+    state_names = _get_tuple_state_names(self._num_states, self._state_name)
+    return tuple([
+        tf.contrib.rnn.LSTMStateTuple(
+            self._batch.state(c_name), self._batch.state(h_name))
+        for c_name, h_name in state_names
+    ])
+
+  def save_state(self, value):
+    # LSTM tuple states
+    state_names = _get_tuple_state_names(self._num_states, self._state_name)
+    save_ops = []
+    for (c_state, h_state), (c_name, h_name) in zip(value, state_names):
+      save_ops.append(self._batch.save_state(c_name, c_state))
+      save_ops.append(self._batch.save_state(h_name, h_state))
+    return tf.group(*save_ops)
+
+
+def _get_tuple_state_names(num_states, base_name):
+  """Returns state names for use with LSTM tuple state."""
+  state_names = [('{}_{}_c'.format(i, base_name), '{}_{}_h'.format(
+      i, base_name)) for i in range(num_states)]
+  return state_names
+
+
+def _split_bidir_tokens(batch):
+  tokens = batch.sequences[data_utils.SequenceWrapper.F_TOKEN_ID]
+  # Tokens have shape [batch, time, 2]
+  # forward and reverse have shape [batch, time].
+  forward, reverse = [
+      tf.squeeze(t, axis=[2]) for t in tf.split(tokens, 2, axis=2)
+  ]
+  return forward, reverse
+
+
+def _filenames_for_data_spec(phase, bidir, pretrain, use_seq2seq):
+  """Returns input filenames for configuration.
+
+  Args:
+    phase: str, 'train', 'test', or 'valid'.
+    bidir: bool, bidirectional model.
+    pretrain: bool, pretraining or classification.
+    use_seq2seq: bool, seq2seq data, only valid if pretrain=True.
+
+  Returns:
+    Tuple of filenames.
+
+  Raises:
+    ValueError: if an invalid combination of arguments is provided that does not
+      map to any data files (e.g. pretrain=False, use_seq2seq=True).
+  """
+  data_spec = (phase, bidir, pretrain, use_seq2seq)
+  data_specs = {
+      ('train', True, True, False): (data_utils.TRAIN_LM,
+                                     data_utils.TRAIN_REV_LM),
+      ('train', True, False, False): (data_utils.TRAIN_BD_CLASS,),
+      ('train', False, True, False): (data_utils.TRAIN_LM,),
+      ('train', False, True, True): (data_utils.TRAIN_SA,),
+      ('train', False, False, False): (data_utils.TRAIN_CLASS,),
+      ('test', True, True, False): (data_utils.TEST_LM,
+                                    data_utils.TRAIN_REV_LM),
+      ('test', True, False, False): (data_utils.TEST_BD_CLASS,),
+      ('test', False, True, False): (data_utils.TEST_LM,),
+      ('test', False, True, True): (data_utils.TEST_SA,),
+      ('test', False, False, False): (data_utils.TEST_CLASS,),
+      ('valid', True, False, False): (data_utils.VALID_BD_CLASS,),
+      ('valid', False, False, False): (data_utils.VALID_CLASS,),
+  }
+  if data_spec not in data_specs:
+    raise ValueError(
+        'Data specification (phase, bidir, pretrain, use_seq2seq) %s not '
+        'supported' % str(data_spec))
+
+  return data_specs[data_spec]
+
+
+def _read_single_sequence_example(file_list, tokens_shape=None):
+  """Reads and parses SequenceExamples from TFRecord-encoded file_list."""
+  tf.logging.info('Constructing TFRecordReader from files: %s', file_list)
+  file_queue = tf.train.string_input_producer(file_list)
+  reader = tf.TFRecordReader()
+  seq_key, serialized_record = reader.read(file_queue)
+  ctx, sequence = tf.parse_single_sequence_example(
+      serialized_record,
+      sequence_features={
+          data_utils.SequenceWrapper.F_TOKEN_ID:
+              tf.FixedLenSequenceFeature(tokens_shape or [], dtype=tf.int64),
+          data_utils.SequenceWrapper.F_LABEL:
+              tf.FixedLenSequenceFeature([], dtype=tf.int64),
+          data_utils.SequenceWrapper.F_WEIGHT:
+              tf.FixedLenSequenceFeature([], dtype=tf.float32),
+      })
+  return seq_key, ctx, sequence
+
+
+def _read_and_batch(data_dir,
+                    fname,
+                    state_name,
+                    state_size,
+                    num_layers,
+                    unroll_steps,
+                    batch_size,
+                    bidir_input=False):
+  """Inputs for text model.
+
+  Args:
+    data_dir: str, directory containing TFRecord files of SequenceExample.
+    fname: str, input file name.
+    state_name: string, key for saved state of LSTM.
+    state_size: int, size of LSTM state.
+    num_layers: int, the number of layers in the LSTM.
+    unroll_steps: int, number of timesteps to unroll for TBTT.
+    batch_size: int, batch size.
+    bidir_input: bool, whether the input is bidirectional. If True, creates 2
+      states, state_name and state_name + '_reverse'.
+
+  Returns:
+    Instance of NextQueuedSequenceBatch
+
+  Raises:
+    ValueError: if file for input specification is not found.
+  """
+  data_path = os.path.join(data_dir, fname)
+  if not tf.gfile.Exists(data_path):
+    raise ValueError('Failed to find file: %s' % data_path)
+
+  tokens_shape = [2] if bidir_input else []
+  seq_key, ctx, sequence = _read_single_sequence_example(
+      [data_path], tokens_shape=tokens_shape)
+  # Set up stateful queue reader.
+  state_names = _get_tuple_state_names(num_layers, state_name)
+  initial_states = {}
+  for c_state, h_state in state_names:
+    initial_states[c_state] = tf.zeros(state_size)
+    initial_states[h_state] = tf.zeros(state_size)
+  if bidir_input:
+    rev_state_names = _get_tuple_state_names(num_layers,
+                                             '{}_reverse'.format(state_name))
+    for rev_c_state, rev_h_state in rev_state_names:
+      initial_states[rev_c_state] = tf.zeros(state_size)
+      initial_states[rev_h_state] = tf.zeros(state_size)
+  batch = tf.contrib.training.batch_sequences_with_states(
+      input_key=seq_key,
+      input_sequences=sequence,
+      input_context=ctx,
+      input_length=tf.shape(sequence['token_id'])[0],
+      initial_states=initial_states,
+      num_unroll=unroll_steps,
+      batch_size=batch_size,
+      allow_small_batch=False,
+      num_threads=4,
+      capacity=batch_size * 10,
+      make_keys_unique=True,
+      make_keys_unique_seed=29392)
+  return batch
+
+
+def inputs(data_dir=None,
+           phase='train',
+           bidir=False,
+           pretrain=False,
+           use_seq2seq=False,
+           state_name='lstm',
+           state_size=None,
+           num_layers=0,
+           batch_size=32,
+           unroll_steps=100):
+  """Inputs for text model.
+
+  Args:
+    data_dir: str, directory containing TFRecord files of SequenceExample.
+    phase: str, dataset for evaluation {'train', 'valid', 'test'}.
+    bidir: bool, bidirectional LSTM.
+    pretrain: bool, whether to read pretraining data or classification data.
+    use_seq2seq: bool, whether to read seq2seq data or the language model data.
+    state_name: string, key for saved state of LSTM.
+    state_size: int, size of LSTM state.
+    num_layers: int, the number of LSTM layers.
+    batch_size: int, batch size.
+    unroll_steps: int, number of timesteps to unroll for TBTT.
+
+  Returns:
+    Instance of VatxtInput (x2 if bidir=True and pretrain=True, i.e. forward and
+      reverse).
+  """
+  with tf.name_scope('inputs'):
+    filenames = _filenames_for_data_spec(phase, bidir, pretrain, use_seq2seq)
+
+    if bidir and pretrain:
+      # Bidirectional pretraining
+      # Requires separate forward and reverse language model data.
+      forward_fname, reverse_fname = filenames
+      forward_batch = _read_and_batch(data_dir, forward_fname, state_name,
+                                      state_size, num_layers, unroll_steps,
+                                      batch_size)
+      state_name_rev = state_name + '_reverse'
+      reverse_batch = _read_and_batch(data_dir, reverse_fname, state_name_rev,
+                                      state_size, num_layers, unroll_steps,
+                                      batch_size)
+      forward_input = VatxtInput(
+          forward_batch, state_name=state_name, num_states=num_layers)
+      reverse_input = VatxtInput(
+          reverse_batch, state_name=state_name_rev, num_states=num_layers)
+      return forward_input, reverse_input
+
+    elif bidir:
+      # Classifier bidirectional LSTM
+      # Shared data source, but separate token/state streams
+      fname, = filenames
+      batch = _read_and_batch(
+          data_dir,
+          fname,
+          state_name,
+          state_size,
+          num_layers,
+          unroll_steps,
+          batch_size,
+          bidir_input=True)
+      forward_tokens, reverse_tokens = _split_bidir_tokens(batch)
+      forward_input = VatxtInput(
+          batch,
+          state_name=state_name,
+          tokens=forward_tokens,
+          num_states=num_layers)
+      reverse_input = VatxtInput(
+          batch,
+          state_name=state_name + '_reverse',
+          tokens=reverse_tokens,
+          num_states=num_layers)
+      return forward_input, reverse_input
+    else:
+      # Unidirectional LM or classifier
+      fname, = filenames
+      batch = _read_and_batch(
+          data_dir,
+          fname,
+          state_name,
+          state_size,
+          num_layers,
+          unroll_steps,
+          batch_size,
+          bidir_input=False)
+      return VatxtInput(batch, state_name=state_name, num_states=num_layers)

adversarial_text/layers.py

+# Copyright 2017 Google, Inc. 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.
+# ==============================================================================
+
+"""Layers for VatxtModel."""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import tensorflow as tf
+
+K = tf.contrib.keras
+
+
+def cl_logits_subgraph(layer_sizes, input_size, num_classes, keep_prob=1.):
+  """Construct multiple ReLU layers with dropout and a linear layer."""
+  subgraph = K.models.Sequential(name='cl_logits')
+  for i, layer_size in enumerate(layer_sizes):
+    if i == 0:
+      subgraph.add(
+          K.layers.Dense(layer_size, activation='relu', input_dim=input_size))
+    else:
+      subgraph.add(K.layers.Dense(layer_size, activation='relu'))
+
+    if keep_prob < 1.:
+      subgraph.add(K.layers.Dropout(keep_prob))
+  subgraph.add(K.layers.Dense(1 if num_classes == 2 else num_classes))
+  return subgraph
+
+
+class Embedding(K.layers.Layer):
+  """Embedding layer with frequency-based normalization and dropout."""
+
+  def __init__(self,
+               vocab_size,
+               embedding_dim,
+               normalize=False,
+               vocab_freqs=None,
+               keep_prob=1.,
+               **kwargs):
+    self.vocab_size = vocab_size
+    self.embedding_dim = embedding_dim
+    self.normalized = normalize
+    self.keep_prob = keep_prob
+
+    if normalize:
+      assert vocab_freqs is not None
+      self.vocab_freqs = tf.constant(
+          vocab_freqs, dtype=tf.float32, shape=(vocab_size, 1))
+
+    super(Embedding, self).__init__(**kwargs)
+
+  def build(self, input_shape):
+    with tf.device('/cpu:0'):
+      self.var = self.add_weight(
+          shape=(self.vocab_size, self.embedding_dim),
+          initializer=tf.random_uniform_initializer(-1., 1.),
+          name='embedding')
+
+    if self.normalized:
+      self.var = self._normalize(self.var)
+
+    super(Embedding, self).build(input_shape)
+
+  def call(self, x):
+    embedded = tf.nn.embedding_lookup(self.var, x)
+    if self.keep_prob < 1.:
+      embedded = tf.nn.dropout(embedded, self.keep_prob)
+    return embedded
+
+  def _normalize(self, emb):
+    weights = self.vocab_freqs / tf.reduce_sum(self.vocab_freqs)
+
+    emb -= tf.reduce_sum(weights * emb, 0, keep_dims=True)
+    emb /= tf.sqrt(1e-6 + tf.reduce_sum(
+        weights * tf.pow(emb, 2.), 0, keep_dims=True))
+    return emb
+
+
+class LSTM(object):
+  """LSTM layer using static_rnn.
+
+  Exposes variables in `trainable_weights` property.
+  """
+
+  def __init__(self, cell_size, num_layers=1, keep_prob=1., name='LSTM'):
+    self.cell_size = cell_size
+    self.num_layers = num_layers
+    self.keep_prob = keep_prob
+    self.reuse = None
+    self.trainable_weights = None
+    self.name = name
+
+  def __call__(self, x, initial_state, seq_length):
+    with tf.variable_scope(self.name, reuse=self.reuse) as vs:
+      cell = tf.contrib.rnn.MultiRNNCell([
+          tf.contrib.rnn.BasicLSTMCell(
+              self.cell_size,
+              forget_bias=0.0,
+              reuse=tf.get_variable_scope().reuse)
+          for _ in xrange(self.num_layers)
+      ])
+
+      # shape(x) = (batch_size, num_timesteps, embedding_dim)
+      # Convert into a time-major list for static_rnn
+      x = tf.unstack(tf.transpose(x, perm=[1, 0, 2]))
+
+      lstm_out, next_state = tf.contrib.rnn.static_rnn(
+          cell, x, initial_state=initial_state, sequence_length=seq_length)
+
+      # Merge time and batch dimensions
+      # shape(lstm_out) = timesteps * (batch_size, cell_size)
+      lstm_out = tf.concat(lstm_out, 0)
+      # shape(lstm_out) = (timesteps*batch_size, cell_size)
+
+      if self.keep_prob < 1.:
+        lstm_out = tf.nn.dropout(lstm_out, self.keep_prob)
+
+      if self.reuse is None:
+        self.trainable_weights = vs.global_variables()
+
+    self.reuse = True
+
+    return lstm_out, next_state
+
+
+class SoftmaxLoss(K.layers.Layer):
+  """Softmax xentropy loss with candidate sampling."""
+
+  def __init__(self,
+               vocab_size,
+               num_candidate_samples=-1,
+               vocab_freqs=None,
+               **kwargs):
+    self.vocab_size = vocab_size
+    self.num_candidate_samples = num_candidate_samples
+    self.vocab_freqs = vocab_freqs
+    super(SoftmaxLoss, self).__init__(**kwargs)
+
+  def build(self, input_shape):
+    input_shape = input_shape[0]
+    with tf.device('/cpu:0'):
+      self.lin_w = self.add_weight(
+          shape=(input_shape[-1], self.vocab_size),
+          name='lm_lin_w',
+          initializer='glorot_uniform')
+      self.lin_b = self.add_weight(
+          shape=(self.vocab_size,),
+          name='lm_lin_b',
+          initializer='glorot_uniform')
+
+    super(SoftmaxLoss, self).build(input_shape)
+
+  def call(self, inputs):
+    x, labels, weights = inputs
+    if self.num_candidate_samples > -1:
+      assert self.vocab_freqs is not None
+      labels = tf.expand_dims(labels, -1)
+      sampled = tf.nn.fixed_unigram_candidate_sampler(
+          true_classes=labels,
+          num_true=1,
+          num_sampled=self.num_candidate_samples,
+          unique=True,
+          range_max=self.vocab_size,
+          unigrams=self.vocab_freqs)
+
+      lm_loss = tf.nn.sampled_softmax_loss(
+          weights=tf.transpose(self.lin_w),
+          biases=self.lin_b,
+          labels=labels,
+          inputs=x,
+          num_sampled=self.num_candidate_samples,
+          num_classes=self.vocab_size,
+          sampled_values=sampled)
+    else:
+      logits = tf.matmul(x, self.lin_w) + self.lin_b
+      lm_loss = tf.nn.sparse_softmax_cross_entropy_with_logits(
+          logits=logits, labels=labels)
+
+    lm_loss = tf.identity(
+        tf.reduce_sum(lm_loss * weights) / _num_labels(weights),
+        name='lm_xentropy_loss')
+    return lm_loss
+
+
+def classification_loss(logits, labels, weights):
+  """Computes cross entropy loss between logits and labels.
+
+  Args:
+    logits: 2-D [timesteps*batch_size, m] float tensor, where m=1 if
+      num_classes=2, otherwise m=num_classes.
+    labels: 1-D [timesteps*batch_size] integer tensor.
+    weights: 2-D [timesteps*batch_size] float tensor.
+
+  Returns:
+    Loss scalar of type float.
+  """
+  inner_dim = logits.get_shape().as_list()[-1]
+  with tf.name_scope('classifier_loss'):
+    # Logistic loss
+    if inner_dim == 1:
+      loss = tf.nn.sigmoid_cross_entropy_with_logits(
+          logits=tf.squeeze(logits), labels=tf.cast(labels, tf.float32))
+    # Softmax loss
+    else:
+      loss = tf.nn.sparse_softmax_cross_entropy_with_logits(
+          logits=logits, labels=labels)
+
+    num_lab = _num_labels(weights)
+    tf.summary.scalar('num_labels', num_lab)
+    return tf.identity(
+        tf.reduce_sum(weights * loss) / num_lab, name='classification_xentropy')
+
+
+def accuracy(logits, targets, weights):
+  """Computes prediction accuracy.
+
+  Args:
+    logits: 2-D classifier logits [timesteps*batch_size, num_classes]
+    targets: 1-D [timesteps*batch_size] integer tensor.
+    weights: 1-D [timesteps*batch_size] float tensor.
+
+  Returns:
+    Accuracy: float scalar.
+  """
+  with tf.name_scope('accuracy'):
+    eq = tf.cast(tf.equal(predictions(logits), targets), tf.float32)
+    return tf.identity(
+        tf.reduce_sum(weights * eq) / _num_labels(weights), name='accuracy')
+
+
+def predictions(logits):
+  """Class prediction from logits."""
+  inner_dim = logits.get_shape().as_list()[-1]
+  with tf.name_scope('predictions'):
+    # For binary classification
+    if inner_dim == 1:
+      pred = tf.cast(tf.greater(tf.squeeze(logits), 0.5), tf.int64)
+    # For multi-class classification
+    else:
+      pred = tf.argmax(logits, 1)
+    return pred
+
+
+def _num_labels(weights):
+  """Number of 1's in weights. Returns 1. if 0."""
+  num_labels = tf.reduce_sum(weights)
+  num_labels = tf.where(tf.equal(num_labels, 0.), 1., num_labels)
+  return num_labels
+
+
+def optimize(loss,
+             global_step,
+             max_grad_norm,
+             lr,
+             lr_decay,
+             sync_replicas=False,
+             replicas_to_aggregate=1,
+             task_id=0):
+  """Builds optimization graph.
+
+  * Creates an optimizer, and optionally wraps with SyncReplicasOptimizer
+  * Computes, clips, and applies gradients
+  * Maintains moving averages for all trainable variables
+  * Summarizes variables and gradients
+
+  Args:
+    loss: scalar loss to minimize.
+    global_step: integer scalar Variable.
+    max_grad_norm: float scalar. Grads will be clipped to this value.
+    lr: float scalar, learning rate.
+    lr_decay: float scalar, learning rate decay rate.
+    sync_replicas: bool, whether to use SyncReplicasOptimizer.
+    replicas_to_aggregate: int, number of replicas to aggregate when using
+      SyncReplicasOptimizer.
+    task_id: int, id of the current task; used to ensure proper initialization
+      of SyncReplicasOptimizer.
+
+  Returns:
+    train_op
+  """
+  with tf.name_scope('optimization'):
+    # Compute gradients.
+    tvars = tf.trainable_variables()
+    grads = tf.gradients(
+        loss,
+        tvars,
+        aggregation_method=tf.AggregationMethod.EXPERIMENTAL_ACCUMULATE_N)
+
+    # Clip non-embedding grads
+    non_embedding_grads_and_vars = [(g, v) for (g, v) in zip(grads, tvars)
+                                    if 'embedding' not in v.op.name]
+    embedding_grads_and_vars = [(g, v) for (g, v) in zip(grads, tvars)
+                                if 'embedding' in v.op.name]
+
+    ne_grads, ne_vars = zip(*non_embedding_grads_and_vars)
+    ne_grads, _ = tf.clip_by_global_norm(ne_grads, max_grad_norm)
+    non_embedding_grads_and_vars = zip(ne_grads, ne_vars)
+
+    grads_and_vars = embedding_grads_and_vars + non_embedding_grads_and_vars
+
+    # Summarize
+    _summarize_vars_and_grads(grads_and_vars)
+
+    # Decaying learning rate
+    lr = tf.train.exponential_decay(
+        lr, global_step, 1, lr_decay, staircase=True)
+    tf.summary.scalar('learning_rate', lr)
+    opt = tf.train.AdamOptimizer(lr)
+
+    # Track the moving averages of all trainable variables.
+    variable_averages = tf.train.ExponentialMovingAverage(0.999, global_step)
+
+    # Apply gradients
+    if sync_replicas:
+      opt = tf.train.SyncReplicasOptimizer(
+          opt,
+          replicas_to_aggregate,
+          variable_averages=variable_averages,
+          variables_to_average=tvars,
+          total_num_replicas=replicas_to_aggregate)
+      apply_gradient_op = opt.apply_gradients(
+          grads_and_vars, global_step=global_step)
+      with tf.control_dependencies([apply_gradient_op]):
+        train_op = tf.no_op(name='train_op')
+
+      # Initialization ops
+      tf.add_to_collection(tf.GraphKeys.QUEUE_RUNNERS,
+                           opt.get_chief_queue_runner())
+      if task_id == 0:  # Chief task
+        local_init_op = opt.chief_init_op
+        tf.add_to_collection('chief_init_op', opt.get_init_tokens_op())
+      else:
+        local_init_op = opt.local_step_init_op
+      tf.add_to_collection('local_init_op', local_init_op)
+      tf.add_to_collection('ready_for_local_init_op',
+                           opt.ready_for_local_init_op)
+    else:
+      # Non-sync optimizer
+      variables_averages_op = variable_averages.apply(tvars)
+      apply_gradient_op = opt.apply_gradients(grads_and_vars, global_step)
+      with tf.control_dependencies([apply_gradient_op, variables_averages_op]):
+        train_op = tf.no_op(name='train_op')
+
+    return train_op
+
+
+def _summarize_vars_and_grads(grads_and_vars):
+  tf.logging.info('Trainable variables:')
+  tf.logging.info('-' * 60)
+  for grad, var in grads_and_vars:
+    tf.logging.info(var)
+
+    def tag(name, v=var):
+      return v.op.name + '_' + name
+
+    # Variable summary
+    mean = tf.reduce_mean(var)
+    tf.summary.scalar(tag('mean'), mean)
+    with tf.name_scope(tag('stddev')):
+      stddev = tf.sqrt(tf.reduce_mean(tf.square(var - mean)))
+    tf.summary.scalar(tag('stddev'), stddev)
+    tf.summary.scalar(tag('max'), tf.reduce_max(var))
+    tf.summary.scalar(tag('min'), tf.reduce_min(var))
+    tf.summary.histogram(tag('histogram'), var)
+
+    # Gradient summary
+    if grad is not None:
+      if isinstance(grad, tf.IndexedSlices):
+        grad_values = grad.values
+      else:
+        grad_values = grad
+
+      tf.summary.histogram(tag('gradient'), grad_values)
+      tf.summary.scalar(tag('gradient_norm'), tf.global_norm([grad_values]))
+    else:
+      tf.logging.info('Var %s has no gradient', var.op.name)

adversarial_text/pretrain.py

+# Copyright 2017 Google, Inc. 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.
+# ==============================================================================
+
+"""Pretrains a recurrent language model.
+
+Computational time:
+  5 days to train 100000 steps on 1 layer 1024 hidden units LSTM,
+  256 embeddings, 400 truncated BP, 64 minibatch and on 4 GPU with
+  SyncReplicasOptimizer, that is the total minibatch is 256.
+"""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import tensorflow as tf
+
+import graphs
+import train_utils
+
+FLAGS = tf.app.flags.FLAGS
+
+
+def main(_):
+  """Trains Language Model."""
+  tf.logging.set_verbosity(tf.logging.INFO)
+  with tf.device(tf.train.replica_device_setter(FLAGS.ps_tasks)):
+    model = graphs.get_model()
+    train_op, loss, global_step = model.language_model_training()
+    train_utils.run_training(train_op, loss, global_step)
+
+
+if __name__ == '__main__':
+  tf.app.run()

adversarial_text/train_classifier.py

+# Copyright 2017 Google, Inc. 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.
+# ==============================================================================
+
+"""Trains LSTM text classification model.
+
+Model trains with adversarial or virtual adversarial training.
+
+Computational time:
+  6 hours to train 10000 steps without adversarial or virtual adversarial
+    training, on 1 layer 1024 hidden units LSTM, 256 embeddings, 400 truncated
+    BP, 64 minibatch and on single GPU.
+
+  12 hours to train 10000 steps with adversarial or virtual adversarial
+    training, with above condition.
+
+To initialize embedding and LSTM cell weights from a pretrained model, set
+FLAGS.pretrained_model_dir to the pretrained model's checkpoint directory.
+"""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import tensorflow as tf
+
+import graphs
+import train_utils
+
+flags = tf.app.flags
+FLAGS = flags.FLAGS
+
+flags.DEFINE_string('pretrained_model_dir', None,
+                    'Directory path to pretrained model to restore from')
+
+
+def main(_):
+  """Trains LSTM classification model."""
+  tf.logging.set_verbosity(tf.logging.INFO)
+  with tf.device(tf.train.replica_device_setter(FLAGS.ps_tasks)):
+    model = graphs.get_model()
+    train_op, loss, global_step = model.classifier_training()
+    train_utils.run_training(
+        train_op,
+        loss,
+        global_step,
+        variables_to_restore=model.pretrained_variables,
+        pretrained_model_dir=FLAGS.pretrained_model_dir)
+
+
+if __name__ == '__main__':
+  tf.app.run()

adversarial_text/train_utils.py

+# Copyright 2017 Google, Inc. 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.
+# ==============================================================================
+
+"""Utilities for training adversarial text models."""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import time
+
+import numpy as np
+import tensorflow as tf
+
+flags = tf.app.flags
+FLAGS = flags.FLAGS
+
+flags.DEFINE_string('master', '', 'Master address.')
+flags.DEFINE_integer('task', 0, 'Task id of the replica running the training.')
+flags.DEFINE_integer('ps_tasks', 0, 'Number of parameter servers.')
+flags.DEFINE_string('train_dir', '/tmp/text_train',
+                    'Directory for logs and checkpoints.')
+flags.DEFINE_integer('max_steps', 1000000, 'Number of batches to run.')
+flags.DEFINE_boolean('log_device_placement', False,
+                     'Whether to log device placement.')
+
+
+def run_training(train_op,
+                 loss,
+                 global_step,
+                 variables_to_restore=None,
+                 pretrained_model_dir=None):
+  """Sets up and runs training loop."""
+  tf.gfile.MakeDirs(FLAGS.train_dir)
+
+  # Create pretrain Saver
+  if pretrained_model_dir:
+    assert variables_to_restore
+    tf.logging.info('Will attempt restore from %s: %s', pretrained_model_dir,
+                    variables_to_restore)
+    saver_for_restore = tf.train.Saver(variables_to_restore)
+
+  # Init ops
+  if FLAGS.sync_replicas:
+    local_init_op = tf.get_collection('local_init_op')[0]
+    ready_for_local_init_op = tf.get_collection('ready_for_local_init_op')[0]
+  else:
+    local_init_op = tf.train.Supervisor.USE_DEFAULT
+    ready_for_local_init_op = tf.train.Supervisor.USE_DEFAULT
+
+  is_chief = FLAGS.task == 0
+  sv = tf.train.Supervisor(
+      logdir=FLAGS.train_dir,
+      is_chief=is_chief,
+      save_summaries_secs=5 * 60,
+      save_model_secs=5 * 60,
+      local_init_op=local_init_op,
+      ready_for_local_init_op=ready_for_local_init_op,
+      global_step=global_step)
+
+  # Delay starting standard services to allow possible pretrained model restore.
+  with sv.managed_session(
+      master=FLAGS.master,
+      config=tf.ConfigProto(log_device_placement=FLAGS.log_device_placement),
+      start_standard_services=False) as sess:
+    # Initialization
+    if is_chief:
+      if pretrained_model_dir:
+        maybe_restore_pretrained_model(sess, saver_for_restore,
+                                       pretrained_model_dir)
+      if FLAGS.sync_replicas:
+        sess.run(tf.get_collection('chief_init_op')[0])
+      sv.start_standard_services(sess)
+
+    sv.start_queue_runners(sess)
+
+    # Training loop
+    global_step_val = 0
+    while not sv.should_stop() and global_step_val < FLAGS.max_steps:
+      global_step_val = train_step(sess, train_op, loss, global_step)
+    sv.stop()
+
+    # Final checkpoint
+    if is_chief:
+      sv.saver.save(sess, sv.save_path, global_step=global_step)
+
+
+def maybe_restore_pretrained_model(sess, saver_for_restore, model_dir):
+  """Restores pretrained model if there is no ckpt model."""
+  ckpt = tf.train.get_checkpoint_state(FLAGS.train_dir)
+  checkpoint_exists = ckpt and ckpt.model_checkpoint_path
+  if checkpoint_exists:
+    tf.logging.info('Checkpoint exists in FLAGS.train_dir; skipping '
+                    'pretraining restore')
+    return
+
+  pretrain_ckpt = tf.train.get_checkpoint_state(model_dir)
+  if not (pretrain_ckpt and pretrain_ckpt.model_checkpoint_path):
+    raise ValueError(
+        'Asked to restore model from %s but no checkpoint found.' % model_dir)
+  saver_for_restore.restore(sess, pretrain_ckpt.model_checkpoint_path)
+
+
+def train_step(sess, train_op, loss, global_step):
+  """Runs a single training step."""
+  start_time = time.time()
+  _, loss_val, global_step_val = sess.run([train_op, loss, global_step])
+  duration = time.time() - start_time
+
+  # Logging
+  if global_step_val % 10 == 0:
+    examples_per_sec = FLAGS.batch_size / duration
+    sec_per_batch = float(duration)
+
+    format_str = ('step %d, loss = %.2f (%.1f examples/sec; %.3f ' 'sec/batch)')
+    tf.logging.info(format_str % (global_step_val, loss_val, examples_per_sec,
+                                  sec_per_batch))
+
+  if np.isnan(loss_val):
+    raise OverflowError('Loss is nan')
+
+  return global_step_val