SVD gradient has not been implemented for input with unknown inner matrix shape.

Raise code

grad_v_shape[:-2])
  a_shape = batch_shape.concatenate([m, n])

  m = a_shape.dims[-2].value
  n = a_shape.dims[-1].value
  # TODO(rmlarsen): Make this work with placeholders.
  if m is None or n is None:
    raise NotImplementedError(
        "SVD gradient has not been implemented for input with unknown "
        "inner matrix shape.")

  s = op.outputs[0]
  u = op.outputs[1]
  v = op.outputs[2]
  s = math_ops.cast(s, a.dtype)

  u