Add instance methods tensor.isnan(), tensor.isinf(), tensor.isfinite() (#37942)
Summary:
Fix https://github.com/pytorch/pytorch/issues/37736
Pull Request resolved: https://github.com/pytorch/pytorch/pull/37942
Differential Revision: D21503150
Pulled By: soumith
fbshipit-source-id: cf6bf57ca67013efe119543f3d9a698473960dec
