def resnet_main()

in example_zoo/tensorflow/models/keras_imagenet_main/official/resnet/resnet_run_loop.py [0:0]


def resnet_main(
    flags_obj, model_function, input_function, dataset_name, shape=None):
  """Shared main loop for ResNet Models.

  Args:
    flags_obj: An object containing parsed flags. See define_resnet_flags()
      for details.
    model_function: the function that instantiates the Model and builds the
      ops for train/eval. This will be passed directly into the estimator.
    input_function: the function that processes the dataset and returns a
      dataset that the estimator can train on. This will be wrapped with
      all the relevant flags for running and passed to estimator.
    dataset_name: the name of the dataset for training and evaluation. This is
      used for logging purpose.
    shape: list of ints representing the shape of the images used for training.
      This is only used if flags_obj.export_dir is passed.

  Returns:
    Dict of results of the run.
  """

  model_helpers.apply_clean(flags.FLAGS)

  # Ensures flag override logic is only executed if explicitly triggered.
  if flags_obj.tf_gpu_thread_mode:
    override_flags_and_set_envars_for_gpu_thread_pool(flags_obj)

  # Creates session config. allow_soft_placement = True, is required for
  # multi-GPU and is not harmful for other modes.
  session_config = tf.ConfigProto(
      inter_op_parallelism_threads=flags_obj.inter_op_parallelism_threads,
      intra_op_parallelism_threads=flags_obj.intra_op_parallelism_threads,
      allow_soft_placement=True)

  distribution_strategy = distribution_utils.get_distribution_strategy(
      flags_core.get_num_gpus(flags_obj), flags_obj.all_reduce_alg)

  # Creates a `RunConfig` that checkpoints every 24 hours which essentially
  # results in checkpoints determined only by `epochs_between_evals`.
  run_config = tf.estimator.RunConfig(
      train_distribute=distribution_strategy,
      session_config=session_config,
      save_checkpoints_secs=60*60*24)

  # Initializes model with all but the dense layer from pretrained ResNet.
  if flags_obj.pretrained_model_checkpoint_path is not None:
    warm_start_settings = tf.estimator.WarmStartSettings(
        flags_obj.pretrained_model_checkpoint_path,
        vars_to_warm_start='^(?!.*dense)')
  else:
    warm_start_settings = None

  classifier = tf.estimator.Estimator(
      model_fn=model_function, model_dir=flags_obj.model_dir, config=run_config,
      warm_start_from=warm_start_settings, params={
          'resnet_size': int(flags_obj.resnet_size),
          'data_format': flags_obj.data_format,
          'batch_size': flags_obj.batch_size,
          'resnet_version': int(flags_obj.resnet_version),
          'loss_scale': flags_core.get_loss_scale(flags_obj),
          'dtype': flags_core.get_tf_dtype(flags_obj),
          'fine_tune': flags_obj.fine_tune
      })

  run_params = {
      'batch_size': flags_obj.batch_size,
      'dtype': flags_core.get_tf_dtype(flags_obj),
      'resnet_size': flags_obj.resnet_size,
      'resnet_version': flags_obj.resnet_version,
      'synthetic_data': flags_obj.use_synthetic_data,
      'train_epochs': flags_obj.train_epochs,
  }
  if flags_obj.use_synthetic_data:
    dataset_name = dataset_name + '-synthetic'

  benchmark_logger = logger.get_benchmark_logger()
  benchmark_logger.log_run_info('resnet', dataset_name, run_params,
                                test_id=flags_obj.benchmark_test_id)

  train_hooks = hooks_helper.get_train_hooks(
      flags_obj.hooks,
      model_dir=flags_obj.model_dir,
      batch_size=flags_obj.batch_size)

  def input_fn_train(num_epochs):
    return input_function(
        is_training=True,
        data_dir=flags_obj.data_dir,
        batch_size=distribution_utils.per_device_batch_size(
            flags_obj.batch_size, flags_core.get_num_gpus(flags_obj)),
        num_epochs=num_epochs,
        dtype=flags_core.get_tf_dtype(flags_obj),
        datasets_num_private_threads=flags_obj.datasets_num_private_threads,
        num_parallel_batches=flags_obj.datasets_num_parallel_batches)

  def input_fn_eval():
    return input_function(
        is_training=False,
        data_dir=flags_obj.data_dir,
        batch_size=distribution_utils.per_device_batch_size(
            flags_obj.batch_size, flags_core.get_num_gpus(flags_obj)),
        num_epochs=1,
        dtype=flags_core.get_tf_dtype(flags_obj))

  if flags_obj.eval_only or not flags_obj.train_epochs:
    # If --eval_only is set, perform a single loop with zero train epochs.
    schedule, n_loops = [0], 1
  else:
    # Compute the number of times to loop while training. All but the last
    # pass will train for `epochs_between_evals` epochs, while the last will
    # train for the number needed to reach `training_epochs`. For instance if
    #   train_epochs = 25 and epochs_between_evals = 10
    # schedule will be set to [10, 10, 5]. That is to say, the loop will:
    #   Train for 10 epochs and then evaluate.
    #   Train for another 10 epochs and then evaluate.
    #   Train for a final 5 epochs (to reach 25 epochs) and then evaluate.
    n_loops = math.ceil(flags_obj.train_epochs / flags_obj.epochs_between_evals)
    schedule = [flags_obj.epochs_between_evals for _ in range(int(n_loops))]
    schedule[-1] = flags_obj.train_epochs - sum(schedule[:-1])  # over counting.

  for cycle_index, num_train_epochs in enumerate(schedule):
    tf.logging.info('Starting cycle: %d/%d', cycle_index, int(n_loops))

    if num_train_epochs:
      classifier.train(input_fn=lambda: input_fn_train(num_train_epochs),
                       hooks=train_hooks, max_steps=flags_obj.max_train_steps)

    tf.logging.info('Starting to evaluate.')

    # flags_obj.max_train_steps is generally associated with testing and
    # profiling. As a result it is frequently called with synthetic data, which
    # will iterate forever. Passing steps=flags_obj.max_train_steps allows the
    # eval (which is generally unimportant in those circumstances) to terminate.
    # Note that eval will run for max_train_steps each loop, regardless of the
    # global_step count.
    eval_results = classifier.evaluate(input_fn=input_fn_eval,
                                       steps=flags_obj.max_train_steps)

    benchmark_logger.log_evaluation_result(eval_results)

    if model_helpers.past_stop_threshold(
        flags_obj.stop_threshold, eval_results['accuracy']):
      break

  if flags_obj.export_dir is not None:
    # Exports a saved model for the given classifier.
    export_dtype = flags_core.get_tf_dtype(flags_obj)
    if flags_obj.image_bytes_as_serving_input:
      input_receiver_fn = functools.partial(
          image_bytes_serving_input_fn, shape, dtype=export_dtype)
    else:
      input_receiver_fn = export.build_tensor_serving_input_receiver_fn(
          shape, batch_size=flags_obj.batch_size, dtype=export_dtype)
    classifier.export_savedmodel(flags_obj.export_dir, input_receiver_fn,
                                 strip_default_attrs=True)
  return eval_results