(default: 25)
  * **find_unused_parameters** (*bool*) -- Traverse the autograd
    graph from all tensors contained in the return value of the
    wrapped module's "forward" function. Parameters that don't
    receive gradients as part of this graph are preemptively
    marked as being ready to be reduced. In addition, parameters
    that may have been used in the wrapped module's "forward"
    function but were not part of loss computation and thus would
    also not receive gradients are preemptively marked as ready to
    be reduced. (default: "False")

  * **check_reduction** -- This argument is deprecated.

  * **gradient_as_bucket_view** (*bool*) -- When set to "True",
    gradients will be views pointing to different offsets of
    "allreduce" communication buckets. This can reduce peak memory
    usage, where the saved memory size will be equal to the total
    gradients size. Moreover, it avoids the overhead of copying
