def aggregate_indexed_slices_gradients()

in scripts/tf_cnn_benchmarks/variable_mgr_util.py [0:0]

• 16 lines of code
• 12 McCabe index (conditional complexity)

def aggregate_indexed_slices_gradients(grads):
  """Aggregates gradients containing `IndexedSlices`s."""
  if len(grads) < 1:
    return None
  elif len(grads) == 1:
    return grads[0]
  else:
    grads = [g for g in grads if g is not None]
    # If any gradient is a `Tensor`, sum them up and return a dense tensor
    # object.
    if any(isinstance(g, ops.Tensor) for g in grads):
      return math_ops.add_n(grads)

    # The following `_as_indexed_slices_list` casts ids of IndexedSlices into
    # int64. It is to make sure the inputs of `concat` all have same the data
    # type.
    grads = math_ops._as_indexed_slices_list(grads)  # pylint: disable=protected-access

    grads = [flatten_nested_indexed_slices(x) for x in grads]
    # Form IndexedSlices out of the concatenated values and indices.
    concat_grad = ops.IndexedSlices(
        array_ops.concat([x.values for x in grads], axis=0),
        array_ops.concat([x.indices for x in grads], axis=0),
        grads[0].dense_shape)

    return concat_grad