tensorflow/models · error · ValueError

When used with `multi_worker_mirrored`, valid values for all

Error message

When used with `multi_worker_mirrored`, valid values for all_reduce_alg are [`ring`, `nccl`].  Supplied value: {}

What it means

Error "When used with `multi_worker_mirrored`, valid values for all_reduce_alg are [`ring`, `nccl`]. Supplied value: {}" thrown in tensorflow/models.

Source

Thrown at official/common/distribute_utils.py:41

  """Return a CollectiveCommunication based on all_reduce_alg.

  Args:
    all_reduce_alg: a string specifying which collective communication to pick,
      or None.

  Returns:
    tf.distribute.experimental.CollectiveCommunication object

  Raises:
    ValueError: if `all_reduce_alg` not in [None, "ring", "nccl"]
  """
  collective_communication_options = {
      None: tf.distribute.experimental.CollectiveCommunication.AUTO,
      "ring": tf.distribute.experimental.CollectiveCommunication.RING,
      "nccl": tf.distribute.experimental.CollectiveCommunication.NCCL
  }
  if all_reduce_alg not in collective_communication_options:
    raise ValueError(
        "When used with `multi_worker_mirrored`, valid values for "
        "all_reduce_alg are [`ring`, `nccl`].  Supplied value: {}".format(
            all_reduce_alg))
  return collective_communication_options[all_reduce_alg]


def _mirrored_cross_device_ops(all_reduce_alg, num_packs):
  """Return a CrossDeviceOps based on all_reduce_alg and num_packs.

  Args:
    all_reduce_alg: a string specifying which cross device op to pick, or None.
    num_packs: an integer specifying number of packs for the cross device op.

  Returns:
    tf.distribute.CrossDeviceOps object or None.

  Raises:
    ValueError: if `all_reduce_alg` not in [None, "nccl", "hierarchical_copy"].

View on GitHub (pinned to e006f5f0d5)

When it happens

Trigger: Thrown at official/common/distribute_utils.py:41 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of tensorflow/models@e006f5f0d5 (2026-08-24). Data as JSON: /api/errors/0896858caefdebd4. Report an issue: GitHub.