Merge branch 'master' into patch-1

research/pcl_rl/full_episode_objective.py

@@ -42,7 +42,8 @@ class Reinforce(objective.Objective):
 
   def get(self, rewards, pads, values, final_values,
           log_probs, prev_log_probs, target_log_probs,
-          entropies, logits):
+          entropies, logits,
+          target_values, final_target_values):
     seq_length = tf.shape(rewards)[0]
 
     not_pad = tf.reshape(1 - pads, [seq_length, -1, self.num_samples])

research/pcl_rl/gym_wrapper.py

@@ -22,6 +22,7 @@ import gym
 import numpy as np
 import random
 
+from six.moves import xrange
 import env_spec
 
 
@@ -92,14 +93,14 @@ class GymWrapper(object):
 
   def step(self, actions):
 
-    def env_step(action):
+    def env_step(env, action):
       action = self.env_spec.convert_action_to_gym(action)
       obs, reward, done, tt = env.step(action)
       obs = self.env_spec.convert_obs_to_list(obs)
       return obs, reward, done, tt
 
     actions = zip(*actions)
-    outputs = [env_step(action)
+    outputs = [env_step(env, action)
                if not done else (self.env_spec.initial_obs(None), 0, True, None)
                for action, env, done in zip(actions, self.envs, self.dones)]
     for i, (_, _, done, _) in enumerate(outputs):

research/pcl_rl/model.py

@@ -57,6 +57,8 @@ class Model(object):
     # summary placeholder
     self.avg_episode_reward = tf.placeholder(
         tf.float32, [], 'avg_episode_reward')
+    self.greedy_episode_reward = tf.placeholder(
+        tf.float32, [], 'greedy_episode_reward')
 
     # sampling placeholders
     self.internal_state = tf.placeholder(tf.float32,
@@ -118,12 +120,13 @@ class Model(object):
     self.prev_log_probs = tf.placeholder(tf.float32, [None, None],
                                          'prev_log_probs')
 
-  def setup(self):
+  def setup(self, train=True):
     """Setup Tensorflow Graph."""
 
     self.setup_placeholders()
 
     tf.summary.scalar('avg_episode_reward', self.avg_episode_reward)
+    tf.summary.scalar('greedy_episode_reward', self.greedy_episode_reward)
 
     with tf.variable_scope('model', reuse=None):
       # policy network
@@ -174,6 +177,7 @@ class Model(object):
           target_p.assign(aa * target_p + (1 - aa) * online_p)
           for online_p, target_p in zip(online_vars, target_vars)])
 
+      if train:
         # evaluate objective
         (self.loss, self.raw_loss, self.regression_target,
          self.gradient_ops, self.summary) = self.objective.get(
@@ -181,8 +185,8 @@ class Model(object):
             self.values[:-1, :],
             self.values[-1, :] * (1 - self.terminated),
             self.log_probs, self.prev_log_probs, self.target_log_probs,
-          self.entropies,
-          self.logits)
+            self.entropies, self.logits, self.target_values[:-1, :],
+            self.target_values[-1, :] * (1 - self.terminated))
 
         self.regression_target = tf.reshape(self.regression_target, [-1])
 
@@ -249,32 +253,42 @@ class Model(object):
   def train_step(self, sess,
                  observations, internal_state, actions,
                  rewards, terminated, pads,
-                 avg_episode_reward=0):
+                 avg_episode_reward=0, greedy_episode_reward=0):
     """Train network using standard gradient descent."""
     outputs = [self.raw_loss, self.gradient_ops, self.summary]
     feed_dict = {self.internal_state: internal_state,
                  self.rewards: rewards,
                  self.terminated: terminated,
                  self.pads: pads,
-                 self.avg_episode_reward: avg_episode_reward}
+                 self.avg_episode_reward: avg_episode_reward,
+                 self.greedy_episode_reward: greedy_episode_reward}
+    time_len = None
     for action_place, action in zip(self.actions, actions):
+      if time_len is None:
+        time_len = len(action)
+      assert time_len == len(action)
       feed_dict[action_place] = action
     for obs_place, obs in zip(self.observations, observations):
+      assert time_len == len(obs)
       feed_dict[obs_place] = obs
 
+    assert len(rewards) == time_len - 1
+
     return sess.run(outputs, feed_dict=feed_dict)
 
 
   def trust_region_step(self, sess,
                         observations, internal_state, actions,
                         rewards, terminated, pads,
-                        avg_episode_reward=0):
+                        avg_episode_reward=0,
+                        greedy_episode_reward=0):
     """Train policy using trust region step."""
     feed_dict = {self.internal_state: internal_state,
                  self.rewards: rewards,
                  self.terminated: terminated,
                  self.pads: pads,
-                 self.avg_episode_reward: avg_episode_reward}
+                 self.avg_episode_reward: avg_episode_reward,
+                 self.greedy_episode_reward: greedy_episode_reward}
     for action_place, action in zip(self.actions, actions):
       feed_dict[action_place] = action
     for obs_place, obs in zip(self.observations, observations):

research/pcl_rl/objective.py

@@ -46,7 +46,8 @@ class Objective(object):
 
   def get(self, rewards, pads, values, final_values,
           log_probs, prev_log_probs, target_log_probs,
-          entropies, logits):
+          entropies, logits,
+          target_values, final_target_values):
     """Get objective calculations."""
     raise NotImplementedError()
 
@@ -101,7 +102,8 @@ class ActorCritic(Objective):
   def __init__(self, learning_rate, clip_norm=5,
                policy_weight=1.0, critic_weight=0.1,
                tau=0.1, gamma=1.0, rollout=10,
-               eps_lambda=0.0, clip_adv=None):
+               eps_lambda=0.0, clip_adv=None,
+               use_target_values=False):
     super(ActorCritic, self).__init__(learning_rate, clip_norm=clip_norm)
     self.policy_weight = policy_weight
     self.critic_weight = critic_weight
@@ -111,14 +113,17 @@ class ActorCritic(Objective):
     self.clip_adv = clip_adv
 
     self.eps_lambda = tf.get_variable(  # TODO: need a better way
-        'eps_lambda', [], initializer=tf.constant_initializer(eps_lambda))
+        'eps_lambda', [], initializer=tf.constant_initializer(eps_lambda),
+        trainable=False)
     self.new_eps_lambda = tf.placeholder(tf.float32, [])
     self.assign_eps_lambda = self.eps_lambda.assign(
-        0.95 * self.eps_lambda + 0.05 * self.new_eps_lambda)
+        0.99 * self.eps_lambda + 0.01 * self.new_eps_lambda)
+    self.use_target_values = use_target_values
 
   def get(self, rewards, pads, values, final_values,
           log_probs, prev_log_probs, target_log_probs,
-          entropies, logits):
+          entropies, logits,
+          target_values, final_target_values):
     not_pad = 1 - pads
     batch_size = tf.shape(rewards)[1]
 
@@ -126,8 +131,15 @@ class ActorCritic(Objective):
     rewards = not_pad * rewards
     value_estimates = not_pad * values
     log_probs = not_pad * sum(log_probs)
+    target_values = not_pad * tf.stop_gradient(target_values)
+    final_target_values = tf.stop_gradient(final_target_values)
 
     sum_rewards = discounted_future_sum(rewards, self.gamma, self.rollout)
+    if self.use_target_values:
+      last_values = shift_values(
+          target_values, self.gamma, self.rollout,
+          final_target_values)
+    else:
       last_values = shift_values(value_estimates, self.gamma, self.rollout,
                                  final_values)
 
@@ -183,7 +195,8 @@ class PCL(ActorCritic):
 
   def get(self, rewards, pads, values, final_values,
           log_probs, prev_log_probs, target_log_probs,
-          entropies, logits):
+          entropies, logits,
+          target_values, final_target_values):
     not_pad = 1 - pads
     batch_size = tf.shape(rewards)[1]
 
@@ -192,6 +205,8 @@ class PCL(ActorCritic):
     log_probs = not_pad * sum(log_probs)
     target_log_probs = not_pad * tf.stop_gradient(sum(target_log_probs))
     relative_log_probs = not_pad * (log_probs - target_log_probs)
+    target_values = not_pad * tf.stop_gradient(target_values)
+    final_target_values = tf.stop_gradient(final_target_values)
 
     # Prepend.
     not_pad = tf.concat([tf.ones([self.rollout - 1, batch_size]),
@@ -210,12 +225,24 @@ class PCL(ActorCritic):
                                 prev_log_probs], 0)
     relative_log_probs = tf.concat([tf.zeros([self.rollout - 1, batch_size]),
                                     relative_log_probs], 0)
+    target_values = tf.concat(
+        [self.gamma ** tf.expand_dims(
+            tf.range(float(self.rollout - 1), 0, -1), 1) *
+         tf.ones([self.rollout - 1, batch_size]) *
+         target_values[0:1, :],
+         target_values], 0)
 
     sum_rewards = discounted_future_sum(rewards, self.gamma, self.rollout)
     sum_log_probs = discounted_future_sum(log_probs, self.gamma, self.rollout)
     sum_prev_log_probs = discounted_future_sum(prev_log_probs, self.gamma, self.rollout)
     sum_relative_log_probs = discounted_future_sum(
         relative_log_probs, self.gamma, self.rollout)
+
+    if self.use_target_values:
+      last_values = shift_values(
+          target_values, self.gamma, self.rollout,
+          final_target_values)
+    else:
       last_values = shift_values(value_estimates, self.gamma, self.rollout,
                                  final_values)
 
@@ -272,7 +299,8 @@ class TRPO(ActorCritic):
 
   def get(self, rewards, pads, values, final_values,
           log_probs, prev_log_probs, target_log_probs,
-          entropies, logits):
+          entropies, logits,
+          target_values, final_target_values):
     not_pad = 1 - pads
     batch_size = tf.shape(rewards)[1]
 
@@ -280,8 +308,16 @@ class TRPO(ActorCritic):
     value_estimates = not_pad * values
     log_probs = not_pad * sum(log_probs)
     prev_log_probs = not_pad * prev_log_probs
+    target_values = not_pad * tf.stop_gradient(target_values)
+    final_target_values = tf.stop_gradient(final_target_values)
 
     sum_rewards = discounted_future_sum(rewards, self.gamma, self.rollout)
+
+    if self.use_target_values:
+      last_values = shift_values(
+          target_values, self.gamma, self.rollout,
+          final_target_values)
+    else:
       last_values = shift_values(value_estimates, self.gamma, self.rollout,
                                  final_values)
 

research/pcl_rl/optimizers.py

@@ -25,6 +25,7 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
+from six.moves import xrange
 import tensorflow as tf
 import numpy as np
 import scipy.optimize

research/pcl_rl/replay_buffer.py

@@ -20,6 +20,7 @@ Implements replay buffer in Python.
 
 import random
 import numpy as np
+from six.moves import xrange
 
 
 class ReplayBuffer(object):
@@ -150,7 +151,7 @@ class PrioritizedReplayBuffer(ReplayBuffer):
   def get_batch(self, n):
     """Get batch of episodes to train on."""
     p = self.sampling_distribution()
-    idxs = np.random.choice(self.cur_size, size=n, replace=False, p=p)
+    idxs = np.random.choice(self.cur_size, size=int(n), replace=False, p=p)
     self.last_batch = idxs
     return [self.buffer[idx] for idx in idxs], p[idxs]
 

research/pcl_rl/trainer.py

@@ -25,6 +25,7 @@ import random
 import os
 import pickle
 
+from six.moves import xrange
 import controller
 import model
 import policy
@@ -92,6 +93,8 @@ flags.DEFINE_bool('update_eps_lambda', False,
                   'Update lambda automatically based on last 100 episodes.')
 flags.DEFINE_float('gamma', 1.0, 'discount')
 flags.DEFINE_integer('rollout', 10, 'rollout')
+flags.DEFINE_bool('use_target_values', False,
+                  'use target network for value estimates')
 flags.DEFINE_bool('fixed_std', True,
                   'fix the std in Gaussian distributions')
 flags.DEFINE_bool('input_prev_actions', True,
@@ -152,6 +155,10 @@ class Trainer(object):
     self.env = gym_wrapper.GymWrapper(self.env_str,
                                       distinct=FLAGS.batch_size // self.num_samples,
                                       count=self.num_samples)
+    self.eval_env = gym_wrapper.GymWrapper(
+        self.env_str,
+        distinct=FLAGS.batch_size // self.num_samples,
+        count=self.num_samples)
     self.env_spec = env_spec.EnvSpec(self.env.get_one())
 
     self.max_step = FLAGS.max_step
@@ -169,7 +176,8 @@ class Trainer(object):
     self.value_opt = FLAGS.value_opt
     assert not self.trust_region_p or self.objective in ['pcl', 'trpo']
     assert self.objective != 'trpo' or self.trust_region_p
-    assert self.value_opt is None or self.critic_weight == 0.0
+    assert self.value_opt is None or self.value_opt == 'None' or \
+        self.critic_weight == 0.0
     self.max_divergence = FLAGS.max_divergence
 
     self.learning_rate = FLAGS.learning_rate
@@ -182,6 +190,7 @@ class Trainer(object):
     self.update_eps_lambda = FLAGS.update_eps_lambda
     self.gamma = FLAGS.gamma
     self.rollout = FLAGS.rollout
+    self.use_target_values = FLAGS.use_target_values
     self.fixed_std = FLAGS.fixed_std
     self.input_prev_actions = FLAGS.input_prev_actions
     self.recurrent = FLAGS.recurrent
@@ -208,8 +217,7 @@ class Trainer(object):
     self.value_hidden_layers = FLAGS.value_hidden_layers
     self.tf_seed = FLAGS.tf_seed
 
-    self.save_trajectories_dir = (
-        FLAGS.save_trajectories_dir or FLAGS.save_dir)
+    self.save_trajectories_dir = FLAGS.save_trajectories_dir
     self.save_trajectories_file = (
         os.path.join(
             self.save_trajectories_dir, self.env_str.replace('-', '_'))
@@ -244,7 +252,8 @@ class Trainer(object):
                  policy_weight=policy_weight,
                  critic_weight=self.critic_weight,
                  tau=tau, gamma=self.gamma, rollout=self.rollout,
-                 eps_lambda=self.eps_lambda, clip_adv=self.clip_adv)
+                 eps_lambda=self.eps_lambda, clip_adv=self.clip_adv,
+                 use_target_values=self.use_target_values)
     elif self.objective in ['reinforce', 'urex']:
       cls = (full_episode_objective.Reinforce
              if self.objective == 'reinforce' else
@@ -322,10 +331,10 @@ class Trainer(object):
         self.num_expert_paths, self.env_str, self.env_spec,
         load_trajectories_file=self.load_trajectories_file)
 
-  def get_controller(self):
+  def get_controller(self, env):
     """Get controller."""
     cls = controller.Controller
-    return cls(self.env, self.env_spec, self.internal_dim,
+    return cls(env, self.env_spec, self.internal_dim,
                use_online_batch=self.use_online_batch,
                batch_by_steps=self.batch_by_steps,
                unify_episodes=self.unify_episodes,
@@ -334,7 +343,7 @@ class Trainer(object):
                cutoff_agent=self.cutoff_agent,
                save_trajectories_file=self.save_trajectories_file,
                use_trust_region=self.trust_region_p,
-               use_value_opt=self.value_opt is not None,
+               use_value_opt=self.value_opt not in [None, 'None'],
                update_eps_lambda=self.update_eps_lambda,
                prioritize_by=self.prioritize_by,
                get_model=self.get_model,
@@ -359,16 +368,19 @@ class Trainer(object):
         saver.restore(sess, ckpt.model_checkpoint_path)
       elif FLAGS.load_path:
         logging.info('restoring from %s', FLAGS.load_path)
-        with gfile.AsUser('distbelief-brain-gpu'):
         saver.restore(sess, FLAGS.load_path)
 
     if FLAGS.supervisor:
       with tf.device(tf.ReplicaDeviceSetter(FLAGS.ps_tasks, merge_devices=True)):
-        self.global_step = tf.train.get_or_create_global_step()
+        self.global_step = tf.contrib.framework.get_or_create_global_step()
         tf.set_random_seed(FLAGS.tf_seed)
-        self.controller = self.get_controller()
+        self.controller = self.get_controller(self.env)
         self.model = self.controller.model
         self.controller.setup()
+        with tf.variable_scope(tf.get_variable_scope(), reuse=True):
+          self.eval_controller = self.get_controller(self.eval_env)
+          self.eval_controller.setup(train=False)
+
         saver = tf.train.Saver(max_to_keep=10)
         step = self.model.global_step
         sv = tf.Supervisor(logdir=FLAGS.save_dir,
@@ -382,10 +394,14 @@ class Trainer(object):
         sess = sv.PrepareSession(FLAGS.master)
     else:
       tf.set_random_seed(FLAGS.tf_seed)
-      self.global_step = tf.train.get_or_create_global_step()
-      self.controller = self.get_controller()
+      self.global_step = tf.contrib.framework.get_or_create_global_step()
+      self.controller = self.get_controller(self.env)
       self.model = self.controller.model
       self.controller.setup()
+      with tf.variable_scope(tf.get_variable_scope(), reuse=True):
+        self.eval_controller = self.get_controller(self.eval_env)
+        self.eval_controller.setup(train=False)
+
       saver = tf.train.Saver(max_to_keep=10)
       sess = tf.Session()
       sess.run(tf.initialize_all_variables())
@@ -414,21 +430,25 @@ class Trainer(object):
 
       (loss, summary,
        total_rewards, episode_rewards) = self.controller.train(sess)
+      _, greedy_episode_rewards = self.eval_controller.eval(sess)
+      self.controller.greedy_episode_rewards = greedy_episode_rewards
       losses.append(loss)
       rewards.append(total_rewards)
       all_ep_rewards.extend(episode_rewards)
 
-      if random.random() < 1 and is_chief and sv and sv._summary_writer:
+      if (random.random() < 0.1 and summary and episode_rewards and
+          is_chief and sv and sv._summary_writer):
         sv.summary_computed(sess, summary)
 
       model_step = sess.run(self.model.global_step)
       if is_chief and step % self.validation_frequency == 0:
         logging.info('at training step %d, model step %d: '
                      'avg loss %f, avg reward %f, '
-                     'episode rewards: %f',
+                     'episode rewards: %f, greedy rewards: %f',
                      step, model_step,
                      np.mean(losses), np.mean(rewards),
-                     np.mean(all_ep_rewards))
+                     np.mean(all_ep_rewards),
+                     np.mean(greedy_episode_rewards))
 
         losses = []
         rewards = []

research/pcl_rl/trust_region.py

@@ -24,6 +24,7 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
+from six.moves import xrange
 import tensorflow as tf
 import numpy as np
 

research/ptn/metrics.py

@@ -19,6 +19,7 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
+from six.moves import xrange
 import tensorflow as tf
 
 slim = tf.contrib.slim
@@ -108,5 +109,3 @@ def add_volume_iou_metrics(inputs, outputs):
   names_to_values['volume_iou'] = tmp_values * 3.0
   names_to_updates['volume_iou'] = tmp_updates
   return names_to_values, names_to_updates
-
-

research/ptn/model_ptn.py

@@ -21,6 +21,7 @@ from __future__ import print_function
 import os
 
 import numpy as np
+from six.moves import xrange
 import tensorflow as tf
 
 import losses

research/ptn/model_rotator.py

@@ -21,6 +21,7 @@ from __future__ import print_function
 import os
 
 import numpy as np
+from six.moves import xrange
 import tensorflow as tf
 
 import input_generator

research/ptn/model_voxel_generation.py

@@ -22,6 +22,7 @@ import abc
 import os
 
 import numpy as np
+from six.moves import xrange
 import tensorflow as tf
 
 import input_generator

research/ptn/pretrain_rotator.py

@@ -21,6 +21,7 @@ from __future__ import print_function
 import os
 
 import numpy as np
+from six.moves import xrange
 import tensorflow as tf
 
 from tensorflow import app

research/ptn/utils.py

@@ -28,6 +28,7 @@ from mpl_toolkits.mplot3d import axes3d as p3  # pylint:disable=unused-import
 import numpy as np
 from PIL import Image
 from skimage import measure
+from six.moves import xrange
 
 import tensorflow as tf
 
@@ -116,4 +117,3 @@ def visualize_voxel_scatter(points, vis_size=128):
           vis_size, vis_size, 3)
   p.close('all')
   return data
-

research/real_nvp/celeba_formatting.py

@@ -30,6 +30,8 @@ python celeba_formatting.py \
 
 """
 
+from __future__ import print_function
+
 import os
 import os.path
 
@@ -70,7 +72,7 @@ def main():
     writer = tf.python_io.TFRecordWriter(file_out)
     for example_idx, img_fn in enumerate(img_fn_list):
         if example_idx % 1000 == 0:
-            print example_idx, "/", num_examples
+            print(example_idx, "/", num_examples)
         image_raw = scipy.ndimage.imread(os.path.join(fn_root, img_fn))
         rows = image_raw.shape[0]
         cols = image_raw.shape[1]

research/real_nvp/imnet_formatting.py

@@ -34,6 +34,8 @@ done
 
 """
 
+from __future__ import print_function
+
 import os
 import os.path
 
@@ -73,10 +75,10 @@ def main():
             file_out = "%s_%05d.tfrecords"
             file_out = file_out % (FLAGS.file_out,
                                    example_idx // n_examples_per_file)
-            print "Writing on:", file_out
+            print("Writing on:", file_out)
             writer = tf.python_io.TFRecordWriter(file_out)
         if example_idx % 1000 == 0:
-            print example_idx, "/", num_examples
+            print(example_idx, "/", num_examples)
         image_raw = scipy.ndimage.imread(os.path.join(fn_root, img_fn))
         rows = image_raw.shape[0]
         cols = image_raw.shape[1]

research/real_nvp/lsun_formatting.py

@@ -29,6 +29,7 @@ python lsun_formatting.py \
     --fn_root [LSUN_FOLDER]
 
 """
+from __future__ import print_function
 
 import os
 import os.path
@@ -68,10 +69,10 @@ def main():
             file_out = "%s_%05d.tfrecords"
             file_out = file_out % (FLAGS.file_out,
                                    example_idx // n_examples_per_file)
-            print "Writing on:", file_out
+            print("Writing on:", file_out)
             writer = tf.python_io.TFRecordWriter(file_out)
         if example_idx % 1000 == 0:
-            print example_idx, "/", num_examples
+            print(example_idx, "/", num_examples)
         image_raw = numpy.array(Image.open(os.path.join(fn_root, img_fn)))
         rows = image_raw.shape[0]
         cols = image_raw.shape[1]

research/real_nvp/real_nvp_multiscale_dataset.py

@@ -23,11 +23,14 @@ $ python real_nvp_multiscale_dataset.py \
 --data_path [DATA_PATH]
 """
 
+from __future__ import print_function
+
 import time
 from datetime import datetime
 import os
 
 import numpy
+from six.moves import xrange
 import tensorflow as tf
 
 from tensorflow import gfile
@@ -1435,10 +1438,10 @@ class RealNVP(object):
             n_equal = int(n_equal)
             n_dash = bar_len - n_equal
             progress_bar = "[" + "=" * n_equal + "-" * n_dash + "]\r"
-            print progress_bar,
+            print(progress_bar, end=' ')
             cost = self.bit_per_dim.eval()
             eval_costs.append(cost)
-        print ""
+        print("")
         return float(numpy.mean(eval_costs))
 
 
@@ -1467,7 +1470,7 @@ def train_model(hps, logdir):
 
             ckpt_state = tf.train.get_checkpoint_state(logdir)
             if ckpt_state and ckpt_state.model_checkpoint_path:
-                print "Loading file %s" % ckpt_state.model_checkpoint_path
+                print("Loading file %s" % ckpt_state.model_checkpoint_path)
                 saver.restore(sess, ckpt_state.model_checkpoint_path)
 
             # Start the queue runners.
@@ -1499,8 +1502,8 @@ def train_model(hps, logdir):
                     format_str = ('%s: step %d, loss = %.2f '
                                   '(%.1f examples/sec; %.3f '
                                   'sec/batch)')
-                    print format_str % (datetime.now(), global_step_val, loss,
-                                        examples_per_sec, duration)
+                    print(format_str % (datetime.now(), global_step_val, loss,
+                                        examples_per_sec, duration))
 
                 if should_eval_summaries:
                     summary_str = outputs[-1]
@@ -1542,24 +1545,24 @@ def evaluate(hps, logdir, traindir, subset="valid", return_val=False):
                 while True:
                     ckpt_state = tf.train.get_checkpoint_state(traindir)
                     if not (ckpt_state and ckpt_state.model_checkpoint_path):
-                        print "No model to eval yet at %s" % traindir
+                        print("No model to eval yet at %s" % traindir)
                         time.sleep(30)
                         continue
-                    print "Loading file %s" % ckpt_state.model_checkpoint_path
+                    print("Loading file %s" % ckpt_state.model_checkpoint_path)
                     saver.restore(sess, ckpt_state.model_checkpoint_path)
 
                     current_step = tf.train.global_step(sess, eval_model.step)
                     if current_step == previous_global_step:
-                        print "Waiting for the checkpoint to be updated."
+                        print("Waiting for the checkpoint to be updated.")
                         time.sleep(30)
                         continue
                     previous_global_step = current_step
 
-                    print "Evaluating..."
+                    print("Evaluating...")
                     bit_per_dim = eval_model.eval_epoch(hps)
-                    print ("Epoch: %d, %s -> %.3f bits/dim"
+                    print("Epoch: %d, %s -> %.3f bits/dim"
                           % (current_step, subset, bit_per_dim))
-                    print "Writing summary..."
+                    print("Writing summary...")
                     summary = tf.Summary()
                     summary.value.extend(
                         [tf.Summary.Value(
@@ -1597,7 +1600,7 @@ def sample_from_model(hps, logdir, traindir):
                     ckpt_state = tf.train.get_checkpoint_state(traindir)
                     if not (ckpt_state and ckpt_state.model_checkpoint_path):
                         if not initialized:
-                            print "No model to eval yet at %s" % traindir
+                            print("No model to eval yet at %s" % traindir)
                             time.sleep(30)
                             continue
                     else:
@@ -1607,7 +1610,7 @@ def sample_from_model(hps, logdir, traindir):
 
                     current_step = tf.train.global_step(sess, eval_model.step)
                     if current_step == previous_global_step:
-                        print "Waiting for the checkpoint to be updated."
+                        print("Waiting for the checkpoint to be updated.")
                         time.sleep(30)
                         continue
                     previous_global_step = current_step

research/real_nvp/real_nvp_utils.py

@@ -19,6 +19,7 @@ r"""Utility functions for Real NVP.
 # pylint: disable=dangerous-default-value
 
 import numpy
+from six.moves import xrange
 import tensorflow as tf
 from tensorflow.python.framework import ops
 

research/slim/datasets/build_imagenet_data.py

@@ -94,6 +94,7 @@ import threading
 
 import google3
 import numpy as np
+from six.moves import xrange
 import tensorflow as tf
 
 tf.app.flags.DEFINE_string('train_directory', '/tmp/',