torch.bincount errors on empty input #9756
Description
Issue description
torch.bincount gives an error when given an empty tensor, rather than just returning zero counts like numpy.bincount. Trips up edge cases when counting filtered data.
Code example
>>> import torch, numpy
>>> numpy.bincount([1]), numpy.bincount([]), numpy.bincount([], minlength=10)
(array([0, 1]), array([], dtype=int64), array([0, 0, 0, 0, 0, 0, 0, 0, 0, 0]))
>>> torch.bincount(torch.LongTensor([]))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
RuntimeError: bincount only supports 1-d non-negative integral inputs.
>>> torch.bincount(torch.LongTensor([]), minlength=10)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
RuntimeError: bincount only supports 1-d non-negative integral inputs.