Function prefetch_join

tensorflow/python/ops/prefetch.py:241–386

Prefetch samples from thread_to_features list. `Unlike `prefetch`, `prefetch_join` runs different ops in different threads. `prefetch_join` can be used to support datasets with many sources. Args: thread_to_features: List of nest structure of tensors for each thread. feed_dict: (Opti

(
    thread_to_features,
    feed_dict={},
    capacity=1,
    num_clients=1,
    timeout_millis=300000,
    closed_exception_types=(errors.OUT_OF_RANGE,),
    ignored_exception_types=(),
    name=None)

@tf_export(v1=["prefetch_join"])
def prefetch_join(
    thread_to_features,
    feed_dict={},
    capacity=1,
    num_clients=1,
    timeout_millis=300000,
    closed_exception_types=(errors.OUT_OF_RANGE,),
    ignored_exception_types=(),
    name=None):
  """Prefetch samples from thread_to_features list.

  `Unlike `prefetch`, `prefetch_join` runs different ops in different threads.
  `prefetch_join` can be used to support datasets with many sources.

  Args:
    thread_to_features: List of nest structure of tensors for each thread.
    feed_dict: (Optional.) A dictionary that maps graph elements to values.
      Each key in `feed_dict` can be one of the following types:
      * `tf.Tensor` or `tf.compat.v1.placeholder`: the value should be a tensor.
      * `tf.SparseTensor`: the value should be a `tf.compat.v1.SparseTensorValue`.
      * a nested tuple of `Tensor`s or `SparseTensor`s, the value should be a
        nested tuple with the same structure that maps to their corresponding
        values as above.
    capacity: (Optional.) Max number of samples to keep in the buffer.
    num_clients: (Optional.) Number of clients of prefetched sample. 1 by
      default.
    timeout_millis: (Optional.) Max milliseconds put op can take, 5 min by
      default.
    closed_exception_types: (Optional.) Exception types indicating that the
      prefetching is normally finished. Defaults to
      `(tf.errors.OutOfRangeError, StopIteration)`.
    ignored_exception_types: (Optional.) Exception types indicating that the
      prefetching can continue. Defaults to `()`.
    name: (Optional.) Name of prefetching operations.

  Returns:
    Prefetched sample.
  """
  if len(thread_to_features) < 1:
    raise ValueError('thread_to_features must has at least one element')

  if name is None:
    name = ops.get_default_graph().unique_name(PREFETCH)
  with ops.name_scope(name):
    local_device = control_flow_ops.no_op().device
    with ops.device(local_device):
      cancel_fetching = gen_tensor_buffer_ops.tensor_buffer_cancel(
          shared_name=name,
          shared_capacity=capacity)
      resume_fetching = gen_tensor_buffer_ops.tensor_buffer_cancel(
          is_cancelled=False,
          shared_name=name,
          shared_capacity=capacity)
      close_fetching = gen_tensor_buffer_ops.tensor_buffer_close(
          shared_name=name,
          shared_capacity=capacity)

  thread_to_tensor_dtypes = []