* add center pooling

* fix yapf formatting

* add unittest

* fix flake8 formatting

* fix isort formatting

* fix isort formatting

* refactor and formatting

* remove top pool from unittext

* remove bottom pool from unittest

* fix bug in torch1.5

* add pytest for assertion

* center_pool -> corner_pool, add docstring

* fix unittest

* add corner_pool.py

* fix some weird logics

* move unittests of ops to a new folder

Co-authored-by: Kai Chen <chenkaidev@gmail.com>

* Bump version to v2.1

* clean minor changes

* More specific change log and clean unnecessary items

* add 2947

* clean optimizer code

* remove duplicate test optimizer

* fix test_config error

* roi_extractors: GRoIE addition

Signed-off-by: Leonardo Rossi <leonardo.rossi@unipr.it>

* Fix bug caused by empty tensor and update benchmark results

Co-authored-by: ZwwWayne <wayne.zw@outlook.com>

* Create model file

* Update README.md

* update model url

Co-authored-by: Jiarui XU <xvjiarui0826@gmail.com>

* Update transforms.py

* format with yapf

Co-authored-by: Kai Chen <chenkaidev@gmail.com>

* Deprecate DistOptimizerHook

* Deprecate DistOptimizerHook

* delete DeprecationWarning

* Add resnext x101 32x8d

* Use consistent name

* Use right img norm

* Fix bug in 32x8d backbone

* performance done, links TBD

* fixed vertical flip TTA

* fixed test

* add doc and one more check

* fixed docs

* add dcn offset doc

* move to doc string

* add lvis dataset

* fixed eval

* fixed test cfg

* add resnext config

* update md

* fixed name

* update model urls

* minor fix

* fixed typo

* use open-mmlab lvis

* update travis

* fixed install

* make class balance as default

* Add upsample_cfg support in FPN

* small fix

* Add multiple extra conv sources

* small logical fix

* Add neck tests for fpn

* Add neck tests for fpn

* fixed several typos

* resolved issues

* Removed extra_convs_source option

* added necks to apis.rst

* change according to comments

* add bbox_fields to expand and min iou crop

* reconfigured configs

* small fix

* added test for random crop and min iou random crop

* small change

* added valid_inds for masks in random crop according to #2802

* added config unit test

* deleted nas fpn config test

* revise according to comments

* add img_fields check in transform.py and test_transform.py

* Added notes for random crop and min iou random crop

* Added notes for random crop and min iou random crop

* Add bbox2label and bbox2mask key correspondence

* Update nas-fpn model
Add fsaf log

fixing link typos

* add tutorials

* use arxiv page

* Update links

* clean empty link

* fix a typo

* fix another typo in comment

* add 3x link

* Update model links

* clean scripts

* fix typo

* Add cls weight in CrossEntropyLoss

* update unittes

* resolve comments

* fix unittest bug

* update model_zoo url

* update mmcv version requirement

* fix async test

* minor fix

* Add regression test

* Fix with copy img

* Revert "Fix with copy img"

This reverts commit 86f07e89a400d3cf73464374c7d1ef3d85649c8e.

* Move test to `test_transform`