def _get_local_init_op():
    local_init_op = _get_first_op_from_collection(ops.GraphKeys.LOCAL_INIT_OP)
    if local_init_op is None:
        op_list = [variables.initialize_local_variables(), data_flow_ops.initialize_all_tables()]
        if op_list:
            local_init_op = control_flow_ops.group(*op_list)
            ops.add_to_collection(ops.GraphKeys.LOCAL_INIT_OP, local_init_op)
    return local_init_op

def _export_graph(graph, saver, checkpoint_path, export_dir,
                  default_graph_signature, named_graph_signatures,
                  exports_to_keep):
  """Exports graph via session_bundle, by creating a Session."""
  with graph.as_default():
    with tf_session.Session('') as session:
      variables.initialize_local_variables()
      data_flow_ops.initialize_all_tables()
      saver.restore(session, checkpoint_path)

      export = exporter.Exporter(saver)
      export.init(init_op=control_flow_ops.group(
          variables.initialize_local_variables(),
          data_flow_ops.initialize_all_tables()),
                  default_graph_signature=default_graph_signature,
                  named_graph_signatures=named_graph_signatures)
      export.export(export_dir, contrib_variables.get_global_step(), session,
                    exports_to_keep=exports_to_keep)

  def run(self,
          num_batches=None,
          graph=None,
          session=None,
          start_queues=True,
          initialize_variables=True,
          **kwargs):
    """Builds and runs the columns of the `DataFrame` and yields batches.

    This is a generator that yields a dictionary mapping column names to
    evaluated columns.

    Args:
      num_batches: the maximum number of batches to produce. If none specified,
        the returned value will iterate through infinite batches.
      graph: the `Graph` in which the `DataFrame` should be built.
      session: the `Session` in which to run the columns of the `DataFrame`.
      start_queues: if true, queues will be started before running and halted
        after producting `n` batches.
      initialize_variables: if true, variables will be initialized.
      **kwargs: Additional keyword arguments e.g. `num_epochs`.

    Yields:
      A dictionary, mapping column names to the values resulting from running
      each column for a single batch.
    """
    if graph is None:
      graph = ops.get_default_graph()
    with graph.as_default():
      if session is None:
        session = sess.Session()
      self_built = self.build(**kwargs)
      keys = list(self_built.keys())
      cols = list(self_built.values())
      if initialize_variables:
        if variables.local_variables():
          session.run(variables.initialize_local_variables())
        if variables.all_variables():
          session.run(variables.initialize_all_variables())
      if start_queues:
        coord = coordinator.Coordinator()
        threads = qr.start_queue_runners(sess=session, coord=coord)
      i = 0
      while num_batches is None or i < num_batches:
        i += 1
        try:
          values = session.run(cols)
          yield collections.OrderedDict(zip(keys, values))
        except errors.OutOfRangeError:
          break
      if start_queues:
        coord.request_stop()
        coord.join(threads)

    def _init_local_init_op(self, local_init_op=USE_DEFAULT):
        """Initializes local_init_op.

    Args:
      local_init_op: `Operation` run for every new supervisor instance. If set
      to USE_DEFAULT create an op based on the `LOCAL_INITIALIZERS` graph
      collection.
    """
        if local_init_op is Supervisor.USE_DEFAULT:
            local_init_op = self._get_first_op_from_collection(ops.GraphKeys.LOCAL_INIT_OP)
            if local_init_op is None:
                op_list = [variables.initialize_local_variables(), data_flow_ops.initialize_all_tables()]
                if op_list:
                    local_init_op = control_flow_ops.group(*op_list)
                    ops.add_to_collection(ops.GraphKeys.LOCAL_INIT_OP, local_init_op)
        self._local_init_op = local_init_op

def run_feeds_iter(output_dict, feed_dicts, restore_checkpoint_path=None):
  """Run `output_dict` tensors with each input in `feed_dicts`.

  If `restore_checkpoint_path` is supplied, restore from checkpoint. Otherwise,
  init all variables.

  Args:
    output_dict: A `dict` mapping string names to `Tensor` objects to run.
      Tensors must all be from the same graph.
    feed_dicts: Iterable of `dict` objects of input values to feed.
    restore_checkpoint_path: A string containing the path to a checkpoint to
      restore.

  Yields:
    A sequence of dicts of values read from `output_dict` tensors, one item
    yielded for each item in `feed_dicts`. Keys are the same as `output_dict`,
    values are the results read from the corresponding `Tensor` in
    `output_dict`.

  Raises:
    ValueError: if `output_dict` or `feed_dicts` is None or empty.
  """
  if not output_dict:
    raise ValueError('output_dict is invalid: %s.' % output_dict)
  if not feed_dicts:
    raise ValueError('feed_dicts is invalid: %s.' % feed_dicts)

  graph = contrib_ops.get_graph_from_inputs(output_dict.values())

  with graph.as_default() as g:
    with tf_session.Session('') as session:
      if restore_checkpoint_path:
        _restore_from_checkpoint(session, g, restore_checkpoint_path)
      else:
        session.run(variables.initialize_all_variables())
      session.run(variables.initialize_local_variables())
      session.run(data_flow_ops.initialize_all_tables())
      coord = coordinator.Coordinator()
      threads = None
      try:
        threads = queue_runner.start_queue_runners(session, coord=coord)
        for f in feed_dicts:
          yield session.run(output_dict, f)
      finally:
        coord.request_stop()
        if threads:
          coord.join(threads, stop_grace_period_secs=120)

    def _init_local_init_op(self, local_init_op=USE_DEFAULT):
        """Initializes local_init_op.

    Args:
      local_init_op: `Operation` run for every new supervisor instance. If set
      to USE_DEFAULT, use the first op from the GraphKeys.LOCAL_INIT_OP
      collection. If the collection is empty, create an op that initializes
      all local variables and all tables.
    """
        if local_init_op is Supervisor.USE_DEFAULT:
            local_init_op = self._get_first_op_from_collection(ops.GraphKeys.LOCAL_INIT_OP)
            if local_init_op is None:
                op_list = [variables.initialize_local_variables(), data_flow_ops.initialize_all_tables()]
                if op_list:
                    local_init_op = control_flow_ops.group(*op_list)
                    ops.add_to_collection(ops.GraphKeys.LOCAL_INIT_OP, local_init_op)
        self._local_init_op = local_init_op

 def _default_local_init_op():
   return control_flow_ops.group(variables.initialize_local_variables(),
                                 data_flow_ops.initialize_all_tables())

def evaluation_loop(master,
                    checkpoint_dir,
                    logdir,
                    num_evals=1,
                    eval_op=None,
                    eval_op_feed_dict=None,
                    final_op=None,
                    final_op_feed_dict=None,
                    summary_op=_USE_DEFAULT,
                    summary_op_feed_dict=None,
                    variables_to_restore=None,
                    eval_interval_secs=60,
                    max_number_of_evaluations=None):
  """Runs TF-Slim's Evaluation Loop.

  Args:
    master: The BNS address of the TensorFlow master.
    checkpoint_dir: The directory where checkpoints are stored.
    logdir: The directory where the TensorFlow summaries are written to.
    num_evals: The number of times to run `eval_op`.
    eval_op: A operation run `num_evals` times.
    eval_op_feed_dict: The feed dictionary to use when executing the `eval_op`.
    final_op: An operation to execute after all of the `eval_op` executions. The
      value of `final_op` is returned.
    final_op_feed_dict: A feed dictionary to use when executing `final_op`.
    summary_op: The summary_op to evaluate after running TF-Slims metric ops. By
      default the summary_op is set to tf.merge_all_summaries().
    summary_op_feed_dict: An optional feed dictionary to use when running the
      `summary_op`.
    variables_to_restore: A list of TensorFlow variables to restore during
      evaluation. If the argument is left as `None` then
      slim.variables.GetVariablesToRestore() is used.
    eval_interval_secs: The minimum number of seconds between evaluations.
    max_number_of_evaluations: the max number of iterations of the evaluation.
      If the value is left as 'None', the evaluation continues indefinitely.
  """
  if summary_op == _USE_DEFAULT:
    summary_op = logging_ops.merge_all_summaries()

  global_step = variables.get_or_create_global_step()

  init_op = control_flow_ops.group(tf_variables.initialize_all_variables(),
                                   tf_variables.initialize_local_variables(),
                                   data_flow_ops.initialize_all_tables())

  saver = tf_saver.Saver(variables_to_restore or
                         variables.get_variables_to_restore())

  summary_writer = summary_io.SummaryWriter(logdir)

  sv = supervisor.Supervisor(graph=ops.get_default_graph(),
                             logdir=logdir,
                             init_op=init_op,
                             summary_op=None,
                             summary_writer=None,
                             global_step=None,
                             saver=saver)

  last_checkpoint = None
  number_of_evaluations = 0
  while True:
    last_checkpoint = wait_for_new_checkpoint(checkpoint_dir, last_checkpoint)
    start = time.time()
    logging.info('Starting evaluation at ' + time.strftime('%Y-%m-%d-%H:%M:%S',
                                                           time.gmtime()))

    with sv.managed_session(master, start_standard_services=False) as sess:
      sv.saver.restore(sess, last_checkpoint)
      sv.start_queue_runners(sess)
      evaluation(sess,
                 num_evals=num_evals,
                 eval_op=eval_op,
                 eval_op_feed_dict=eval_op_feed_dict,
                 final_op=final_op,
                 final_op_feed_dict=final_op_feed_dict,
                 summary_op=summary_op,
                 summary_op_feed_dict=summary_op_feed_dict,
                 summary_writer=summary_writer,
                 global_step=global_step)

    logging.info('Finished evaluation at ' + time.strftime('%Y-%m-%d-%H:%M:%S',
                                                           time.gmtime()))
    number_of_evaluations += 1
    if (max_number_of_evaluations and
        number_of_evaluations >= max_number_of_evaluations):
      logging.info('Reached max_number_of_evaluations=%s. Exit',
                   max_number_of_evaluations)
      break

    time_to_next_eval = start + eval_interval_secs - time.time()
    if time_to_next_eval > 0:
      time.sleep(time_to_next_eval)

def train(
    train_op,
    logdir,
    log_every_n_steps=1,
    graph=None,
    master='',
    is_chief=True,
    global_step=None,
    number_of_steps=None,
    init_op=_USE_DEFAULT,
    init_feed_dict=None,
    init_fn=None,
    summary_op=_USE_DEFAULT,
    save_summaries_secs=600,
    startup_delay_steps=0,
    saver=None,
    save_interval_secs=600,
    sync_optimizer=None):
  """Runs a training loop using a TensorFlow supervisor.

  When the sync_optimizer is supplied, gradient updates are applied
  synchronously. Otherwise, gradient updates are applied asynchronous.

  Args:
    train_op: A `Tensor` that, when executed, will apply the gradients and
      return the loss value.
    logdir: the directory where training logs are written to.
    log_every_n_steps: The frequency, in terms of global steps, that the loss
      and global step and logged.
    graph: The graph to pass to the supervisor. If no graph is supplied the
      default graph is used.
    master: The BNS name of the tensorflow master.
    is_chief: Specifies whether or not the training is being run by the primary
      replica during replica training.
    global_step: The `Tensor` representing the global step. If left as `None`,
      then slim.variables.get_or_create_global_step() is used.
    number_of_steps: The max number of gradient steps to take during training.
      If the value is left as None, training proceeds indefinitely.
    init_op: The initialization operation.
    init_feed_dict: A feed dictionary to use when executing the `init_op`.
    init_fn: An optional callable to be executed after `init_op` is called. The
      callable must accept one argument, the session being initialized.
    summary_op: The summary operation.
    save_summaries_secs: How often, in seconds, to save summaries.
    startup_delay_steps: The number of steps to wait for before beginning. Note
      that this must be 0 if a sync_optimizer is supplied.
    saver: Saver to save checkpoints. If none, a default one will be created
      and used.
    save_interval_secs: How often, in seconds, to save the model to `logdir`.
    sync_optimizer: an instance of tf.train.SyncReplicasOptimizer. If the
      argument is supplied, gradient updates will be synchronous. If left as
      `None`, gradient updates will be asynchronous.

  Returns:
    the value of the loss function after training.

  Raises:
    ValueError: if `train_op` is empty or if `startup_delay_steps` is
      non-zero when `sync_optimizer` is supplied, or if `number_of_steps` is
      negative.
  """
  if train_op is None:
    raise ValueError('train_op cannot be None.')

  if sync_optimizer and startup_delay_steps > 0:
    raise ValueError(
        'startup_delay_steps must be zero when sync_optimizer is supplied.')

  if number_of_steps is not None and number_of_steps <= 0:
    raise ValueError(
        '`number_of_steps` must be either None or a positive number.')

  graph = graph or ops.get_default_graph()
  if global_step is None:
    global_step = variables.get_or_create_global_step()
  saver = saver or tf_saver.Saver()

  if init_op is None:
    init_op = control_flow_ops.group(
        tf_variables.initialize_all_variables(),
        tf_variables.initialize_local_variables(),
        tf_variables.initialize_all_tables())

  if summary_op == _USE_DEFAULT:
    summary_op = logging_ops.merge_all_summaries()

  local_init_op = None
  cleanup_op = None

  if is_chief and sync_optimizer:
    if not isinstance(sync_optimizer,
                      sync_replicas_optimizer.SyncReplicasOptimizer):
      raise ValueError(
          '`sync_optimizer` must be a tf.train.SyncReplicasOptimizer')

    # Need to create these BEFORE the supervisor finalizes the graph:
    local_init_op = sync_optimizer.get_init_tokens_op()
    chief_queue_runner = sync_optimizer.get_chief_queue_runner()
    cleanup_op = sync_optimizer.get_clean_up_op()

#.........这里部分代码省略.........

def train(train_op,
          logdir,
          train_step_fn=train_step,
          train_step_kwargs=_USE_DEFAULT,
          log_every_n_steps=1,
          graph=None,
          master='',
          is_chief=True,
          global_step=None,
          number_of_steps=None,
          init_op=_USE_DEFAULT,
          init_feed_dict=None,
          local_init_op=_USE_DEFAULT,
          init_fn=None,
          ready_op=_USE_DEFAULT,
          summary_op=_USE_DEFAULT,
          save_summaries_secs=600,
          summary_writer=_USE_DEFAULT,
          startup_delay_steps=0,
          saver=None,
          save_interval_secs=600,
          sync_optimizer=None,
          session_config=None):
  """Runs a training loop using a TensorFlow supervisor.

  When the sync_optimizer is supplied, gradient updates are applied
  synchronously. Otherwise, gradient updates are applied asynchronous.

  Args:
    train_op: A `Tensor` that, when executed, will apply the gradients and
      return the loss value.
    logdir: The directory where training logs are written to. If None, model
      checkpoints and summaries will not be written.
    train_step_fn: The function to call in order to execute a single gradient
      step. The function must have take exactly four arguments: the current
      session, the `train_op` `Tensor`, a global step `Tensor` and a dictionary.
    train_step_kwargs: A dictionary which is passed to the `train_step_fn`. By
      default, two `Boolean`, scalar ops called "should_stop" and "should_log"
      are provided.
    log_every_n_steps: The frequency, in terms of global steps, that the loss
      and global step and logged.
    graph: The graph to pass to the supervisor. If no graph is supplied the
      default graph is used.
    master: The BNS name of the tensorflow master.
    is_chief: Specifies whether or not the training is being run by the primary
      replica during replica training.
    global_step: The `Tensor` representing the global step. If left as `None`,
      then slim.variables.get_or_create_global_step() is used.
    number_of_steps: The max number of gradient steps to take during training.
      If the value is left as None, training proceeds indefinitely.
    init_op: The initialization operation. If left to its default value, then
      the session is initialized by calling `tf.initialize_all_variables()`.
    init_feed_dict: A feed dictionary to use when executing the `init_op`.
    local_init_op: The local initialization operation. If left to its default
      value, then the session is initialized by calling
      `tf.initialize_local_variables()` and `tf.initialize_all_tables()`.
    init_fn: An optional callable to be executed after `init_op` is called. The
      callable must accept one argument, the session being initialized.
    ready_op: Operation to check if the model is ready to use. If left to its
      default value, then the session checks for readiness by calling
      `tf.report_uninitialized_variables()`.
    summary_op: The summary operation.
    save_summaries_secs: How often, in seconds, to save summaries.
    summary_writer: `SummaryWriter` to use.  Can be `None`
      to indicate that no summaries should be written. If unset, we
      create a SummaryWriter.
    startup_delay_steps: The number of steps to wait for before beginning. Note
      that this must be 0 if a sync_optimizer is supplied.
    saver: Saver to save checkpoints. If None, a default one will be created
      and used.
    save_interval_secs: How often, in seconds, to save the model to `logdir`.
    sync_optimizer: an instance of tf.train.SyncReplicasOptimizer. If the
      argument is supplied, gradient updates will be synchronous. If left as
      `None`, gradient updates will be asynchronous.
    session_config: An instance of `tf.ConfigProto` that will be used to
      configure the `Session`. If left as `None`, the default will be used.

  Returns:
    the value of the loss function after training.

  Raises:
    ValueError: if `train_op` is empty or if `startup_delay_steps` is
      non-zero when `sync_optimizer` is supplied, or if `number_of_steps` is
      negative.
  """
  if train_op is None:
    raise ValueError('train_op cannot be None.')

  if logdir is None:
    if summary_op != _USE_DEFAULT:
      raise ValueError('Cannot provide summary_op because logdir=None')
    if saver is not None:
      raise ValueError('Cannot provide saver because logdir=None')

  if sync_optimizer and startup_delay_steps > 0:
    raise ValueError(
        'startup_delay_steps must be zero when sync_optimizer is supplied.')

  if number_of_steps is not None and number_of_steps <= 0:
    raise ValueError(
#.........这里部分代码省略.........

def evaluate_once(checkpoint_path,
                  logdir,
                  master='',
                  num_evals=1,
                  eval_op=None,
                  eval_op_feed_dict=None,
                  final_op=None,
                  final_op_feed_dict=None,
                  summary_op=_USE_DEFAULT,
                  summary_op_feed_dict=None,
                  variables_to_restore=None,
                  session_config=None):
  """Evaluates the model at the given checkpoint path.

  Args:
    checkpoint_path: The path to a checkpoint to use for evaluation.
    logdir: The directory where the TensorFlow summaries are written to.
    master: The BNS address of the TensorFlow master.
    num_evals: The number of times to run `eval_op`.
    eval_op: A operation run `num_evals` times.
    eval_op_feed_dict: The feed dictionary to use when executing the `eval_op`.
    final_op: An operation to execute after all of the `eval_op` executions. The
      value of `final_op` is returned.
    final_op_feed_dict: A feed dictionary to use when executing `final_op`.
    summary_op: The summary_op to evaluate after running TF-Slims metric ops. By
      default the summary_op is set to tf.merge_all_summaries().
    summary_op_feed_dict: An optional feed dictionary to use when running the
      `summary_op`.
    variables_to_restore: A list of TensorFlow variables to restore during
      evaluation. If the argument is left as `None` then
      slim.variables.GetVariablesToRestore() is used.
    session_config: An instance of `tf.ConfigProto` that will be used to
      configure the `Session`. If left as `None`, the default will be used.

  Returns:
    The value of `final_op` or `None` if `final_op` is `None`.
  """
  if summary_op == _USE_DEFAULT:
    summary_op = logging_ops.merge_all_summaries()

  global_step = variables.get_or_create_global_step()

  init_op = control_flow_ops.group(tf_variables.initialize_all_variables(),
                                   tf_variables.initialize_local_variables(),
                                   data_flow_ops.initialize_all_tables())

  saver = tf_saver.Saver(variables_to_restore or
                         variables.get_variables_to_restore())

  summary_writer = summary_io.SummaryWriter(logdir)

  sv = supervisor.Supervisor(graph=ops.get_default_graph(),
                             logdir=logdir,
                             init_op=init_op,
                             summary_op=None,
                             summary_writer=None,
                             global_step=None,
                             saver=None)

  logging.info('Starting evaluation at ' + time.strftime('%Y-%m-%d-%H:%M:%S',
                                                         time.gmtime()))
  with sv.managed_session(
      master, start_standard_services=False, config=session_config) as sess:
    saver.restore(sess, checkpoint_path)
    sv.start_queue_runners(sess)
    final_op_value = evaluation(sess,
                                num_evals=num_evals,
                                eval_op=eval_op,
                                eval_op_feed_dict=eval_op_feed_dict,
                                final_op=final_op,
                                final_op_feed_dict=final_op_feed_dict,
                                summary_op=summary_op,
                                summary_op_feed_dict=summary_op_feed_dict,
                                summary_writer=summary_writer,
                                global_step=global_step)

  logging.info('Finished evaluation at ' + time.strftime('%Y-%m-%d-%H:%M:%S',
                                                         time.gmtime()))

  return final_op_value