Add deprecated metric utility functions back to functional (#5062)

* add back *deprecated* metric utility functions to functional

* pep

* pep

* suggestions

* move

Co-authored-by: Jirka Borovec <[email protected]>

Author: teddykoker

CHANGELOG.md

@@ -80,9 +80,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 ### Changed
 
-- Removed `multiclass_roc` and `multiclass_precision_recall_curve`, use `roc` and `precision_recall_curve` instead ([#4549](https://github.com/PyTorchLightning/pytorch-lightning/pull/4549))
 - Tuner algorithms will be skipped if `fast_dev_run=True` ([#3903](https://github.com/PyTorchLightning/pytorch-lightning/pull/3903))
-- WandbLogger does not force wandb `reinit` arg to True anymore and creates a run only when needed ([#4648](https://github.com/PyTorchLightning/pytorch-lightning/pull/4648))
+- `WandbLogger` does not force wandb `reinit` arg to True anymore and creates a run only when needed ([#4648](https://github.com/PyTorchLightning/pytorch-lightning/pull/4648))
 - Changed `automatic_optimization` to be a model attribute ([#4602](https://github.com/PyTorchLightning/pytorch-lightning/pull/4602))
 - Changed `Simple Profiler` report to order by percentage time spent + num calls ([#4880](https://github.com/PyTorchLightning/pytorch-lightning/pull/4880))
 - Simplify optimization Logic ([#4984](https://github.com/PyTorchLightning/pytorch-lightning/pull/4984))
@@ -100,6 +99,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 ### Removed
 
 - Removed `reorder` parameter of the `auc` metric ([#5004](https://github.com/PyTorchLightning/pytorch-lightning/pull/5004))
+- Removed `multiclass_roc` and `multiclass_precision_recall_curve`, use `roc` and `precision_recall_curve` instead ([#4549](https://github.com/PyTorchLightning/pytorch-lightning/pull/4549))
 
 ### Fixed
 

pytorch_lightning/metrics/functional/__init__.py

@@ -41,3 +41,4 @@
 from pytorch_lightning.metrics.functional.roc import roc
 from pytorch_lightning.metrics.functional.self_supervised import embedding_similarity
 from pytorch_lightning.metrics.functional.ssim import ssim
+from pytorch_lightning.metrics.utils import to_categorical, to_onehot