Error in NMS function

[attibalazs]

Hi all,

I'm getting an error when training the model in the NMS function, it shows up after a few epochs, its hard to debug.

  File "/lib/python3.6/site-packages/fastai/callback.py", line 241, in _call_and_update
    new = ifnone(getattr(cb, f'on_{cb_name}')(**self.state_dict, **kwargs), dict())
  File "/lib/python3.6/site-packages/object_detection_fastai/callbacks/callbacks.py", line 127, in on_batch_end
    to_keep = nms(bbox_pred, scores, self.nms_thresh)
  File "/lib/python3.6/site-packages/object_detection_fastai/helper/object_detection_helper.py", line 158, in nms
    idx_first = mask_keep.nonzero().min().item()
**RuntimeError: operation does not have an identity.**

when I checked the code it doesn't look like idx_first is being used anywhere, is this legacy, should it be removed ?

thanks,
atti