Import new kaggle solution

+# Copyright 2016 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.
+"""Contains a collection of util functions for training and evaluating."""
+
+import numpy
+import tensorflow as tf
+from tensorflow import logging
+
+try:
+  xrange  # Python 2
+except NameError:
+  xrange = range  # Python 3
+
+
+def Dequantize(feat_vector, max_quantized_value=2, min_quantized_value=-2):
+  """Dequantize the feature from the byte format to the float format.
+
+  Args:
+    feat_vector: the input 1-d vector.
+    max_quantized_value: the maximum of the quantized value.
+    min_quantized_value: the minimum of the quantized value.
+
+  Returns:
+    A float vector which has the same shape as feat_vector.
+  """
+  assert max_quantized_value > min_quantized_value
+  quantized_range = max_quantized_value - min_quantized_value
+  scalar = quantized_range / 255.0
+  bias = (quantized_range / 512.0) + min_quantized_value
+  return feat_vector * scalar + bias
+
+
+def MakeSummary(name, value):
+  """Creates a tf.Summary proto with the given name and value."""
+  summary = tf.Summary()
+  val = summary.value.add()
+  val.tag = str(name)
+  val.simple_value = float(value)
+  return summary
+
+
+def AddGlobalStepSummary(summary_writer,
+                         global_step_val,
+                         global_step_info_dict,
+                         summary_scope="Eval"):
+  """Add the global_step summary to the Tensorboard.
+
+  Args:
+    summary_writer: Tensorflow summary_writer.
+    global_step_val: a int value of the global step.
+    global_step_info_dict: a dictionary of the evaluation metrics calculated for
+      a mini-batch.
+    summary_scope: Train or Eval.
+
+  Returns:
+    A string of this global_step summary
+  """
+  this_hit_at_one = global_step_info_dict["hit_at_one"]
+  this_perr = global_step_info_dict["perr"]
+  this_loss = global_step_info_dict["loss"]
+  examples_per_second = global_step_info_dict.get("examples_per_second", -1)
+
+  summary_writer.add_summary(
+      MakeSummary("GlobalStep/" + summary_scope + "_Hit@1", this_hit_at_one),
+      global_step_val)
+  summary_writer.add_summary(
+      MakeSummary("GlobalStep/" + summary_scope + "_Perr", this_perr),
+      global_step_val)
+  summary_writer.add_summary(
+      MakeSummary("GlobalStep/" + summary_scope + "_Loss", this_loss),
+      global_step_val)
+
+  if examples_per_second != -1:
+    summary_writer.add_summary(
+        MakeSummary("GlobalStep/" + summary_scope + "_Example_Second",
+                    examples_per_second), global_step_val)
+
+  summary_writer.flush()
+  info = (
+      "global_step {0} | Batch Hit@1: {1:.3f} | Batch PERR: {2:.3f} | Batch "
+      "Loss: {3:.3f} | Examples_per_sec: {4:.3f}").format(
+          global_step_val, this_hit_at_one, this_perr, this_loss,
+          examples_per_second)
+  return info
+
+
+def AddEpochSummary(summary_writer,
+                    global_step_val,
+                    epoch_info_dict,
+                    summary_scope="Eval"):
+  """Add the epoch summary to the Tensorboard.
+
+  Args:
+    summary_writer: Tensorflow summary_writer.
+    global_step_val: a int value of the global step.
+    epoch_info_dict: a dictionary of the evaluation metrics calculated for the
+      whole epoch.
+    summary_scope: Train or Eval.
+
+  Returns:
+    A string of this global_step summary
+  """
+  epoch_id = epoch_info_dict["epoch_id"]
+  avg_hit_at_one = epoch_info_dict["avg_hit_at_one"]
+  avg_perr = epoch_info_dict["avg_perr"]
+  avg_loss = epoch_info_dict["avg_loss"]
+  aps = epoch_info_dict["aps"]
+  gap = epoch_info_dict["gap"]
+  mean_ap = numpy.mean(aps)
+
+  summary_writer.add_summary(
+      MakeSummary("Epoch/" + summary_scope + "_Avg_Hit@1", avg_hit_at_one),
+      global_step_val)
+  summary_writer.add_summary(
+      MakeSummary("Epoch/" + summary_scope + "_Avg_Perr", avg_perr),
+      global_step_val)
+  summary_writer.add_summary(
+      MakeSummary("Epoch/" + summary_scope + "_Avg_Loss", avg_loss),
+      global_step_val)
+  summary_writer.add_summary(
+      MakeSummary("Epoch/" + summary_scope + "_MAP", mean_ap), global_step_val)
+  summary_writer.add_summary(
+      MakeSummary("Epoch/" + summary_scope + "_GAP", gap), global_step_val)
+  summary_writer.flush()
+
+  info = ("epoch/eval number {0} | Avg_Hit@1: {1:.3f} | Avg_PERR: {2:.3f} "
+          "| MAP: {3:.3f} | GAP: {4:.3f} | Avg_Loss: {5:3f} | num_classes: {6}"
+         ).format(epoch_id, avg_hit_at_one, avg_perr, mean_ap, gap, avg_loss,
+                  len(aps))
+  return info
+
+
+def GetListOfFeatureNamesAndSizes(feature_names, feature_sizes):
+  """Extract the list of feature names and the dimensionality of each feature
+
+     from string of comma separated values.
+
+  Args:
+    feature_names: string containing comma separated list of feature names
+    feature_sizes: string containing comma separated list of feature sizes
+
+  Returns:
+    List of the feature names and list of the dimensionality of each feature.
+    Elements in the first/second list are strings/integers.
+  """
+  list_of_feature_names = [
+      feature_names.strip() for feature_names in feature_names.split(",")
+  ]
+  list_of_feature_sizes = [
+      int(feature_sizes) for feature_sizes in feature_sizes.split(",")
+  ]
+  if len(list_of_feature_names) != len(list_of_feature_sizes):
+    logging.error("length of the feature names (=" +
+                  str(len(list_of_feature_names)) + ") != length of feature "
+                  "sizes (=" + str(len(list_of_feature_sizes)) + ")")
+
+  return list_of_feature_names, list_of_feature_sizes
+
+
+def clip_gradient_norms(gradients_to_variables, max_norm):
+  """Clips the gradients by the given value.
+
+  Args:
+    gradients_to_variables: A list of gradient to variable pairs (tuples).
+    max_norm: the maximum norm value.
+
+  Returns:
+    A list of clipped gradient to variable pairs.
+  """
+  clipped_grads_and_vars = []
+  for grad, var in gradients_to_variables:
+    if grad is not None:
+      if isinstance(grad, tf.IndexedSlices):
+        tmp = tf.clip_by_norm(grad.values, max_norm)
+        grad = tf.IndexedSlices(tmp, grad.indices, grad.dense_shape)
+      else:
+        grad = tf.clip_by_norm(grad, max_norm)
+    clipped_grads_and_vars.append((grad, var))
+  return clipped_grads_and_vars
+
+
+def combine_gradients(tower_grads):
+  """Calculate the combined gradient for each shared variable across all towers.
+
+  Note that this function provides a synchronization point across all towers.
+
+  Args:
+    tower_grads: List of lists of (gradient, variable) tuples. The outer list is
+      over individual gradients. The inner list is over the gradient calculation
+      for each tower.
+
+  Returns:
+     List of pairs of (gradient, variable) where the gradient has been summed
+     across all towers.
+  """
+  filtered_grads = [
+      [x for x in grad_list if x[0] is not None] for grad_list in tower_grads
+  ]
+  final_grads = []
+  for i in xrange(len(filtered_grads[0])):
+    grads = [filtered_grads[t][i] for t in xrange(len(filtered_grads))]
+    grad = tf.stack([x[0] for x in grads], 0)
+    grad = tf.reduce_sum(grad, 0)
+    final_grads.append((
+        grad,
+        filtered_grads[0][i][1],
+    ))
+
+  return final_grads