Function check_backward_validity

utils/gradient_checkpoint.py:23–25

(inputs: Iterable[Any])

def check_backward_validity(inputs: Iterable[Any]) -> None:
    if not any(inp.requires_grad for inp in inputs if isinstance(inp, torch.Tensor)):
        warnings.warn("None of the inputs have requires_grad=True. Gradients will be None")


# We can't know if the run_fn will internally move some args to different devices,