Implement histogram operator on CPU (#58780)
Summary:
The existing [torch.histc](https://pytorch.org/docs/stable/generated/torch.histc.html) operator is limited in comparison to [numpy.histogram](https://numpy.org/doc/stable/reference/generated/numpy.histogram.html). This PR adds torch.histogram on CPU. The new operator replicates numpy.histogram's behavior, including support for caller-specified bin edges and weights. It was motivated by previous community requests for histogram.
The implementation was [benchmarked](https://docs.google.com/spreadsheets/d/1xCR0jODchVvwdVSAjiLsNCkmyictA6j1LNfDpWOafjw/edit?usp=sharing) against numpy.histogram as well as torch.histc. This implementation is weakly faster than numpy.histogram across all types of inputs tested, and performs in line with torch.histc for the limited inputs histc supports.
mruberry
Pull Request resolved: https://github.com/pytorch/pytorch/pull/58780
Test Plan:
Added unit tests, OpInfo for the new torch.histogram operator.
Tested execution time on a variety of input sizes and compared to numpy.histogram performance: https://docs.google.com/spreadsheets/d/1xCR0jODchVvwdVSAjiLsNCkmyictA6j1LNfDpWOafjw/edit?usp=sharing
Reviewed By: ezyang
Differential Revision: D29134626
Pulled By: saketh-are
fbshipit-source-id: f2773085de1697f6bc6ffdeffe9a81267f51bdfc
