* add a abvious import

* add a assert for CLASSES in XMLDataset

* change to get

* add voc tiny dataset

* add tiny voc

* add voc init test

* change to smalle iamge

* add xmlsubclass check

* add smaller image

* add comment for assert

* Add regression test and test data

* Add fix for empty gt images

* Trigger CI build

* refactor get_subset_by_classes

* reformat and fix docstring

* [refactor]: move get_subset_by_classes to _filter_imgs

* make img_ids consistent

* resolve comments

* simplify logics

* add warning

* add warning

* add warning

Co-authored-by: mmeendez8 <miguelmndez@gmail.com>

* update docstring formats

* fix :func:

* minor update

* add docstring for pipelines

* add docs string for transform pipeline

* add dataset docs

* resovle comments

* refactor table

* resovle comments

* delete __repr__

* resolve comments

* minor update

* update readme

* minor update

* rename api

* add RepeatFactorDataset

* add docs and test

* rename to ClassBalancedDataset

* fixed typo

* consummating xml_style.py

* Update xml_style.py

update xml_style.py

* Update xml_style.py

fix the format

* Change .format to f-string

* Resolve comments

* Fix missing change

* use mmcv Registry instead of mmdet

* merged registry and builder

* merge dataset builder registry

* remove circulate import in bbox

* rename registry to builder

* support to train subsets of coco dataset

* add template config

* Add docstrings

* Refactor (classes): modity API to be consistent with PR 2408

* Add support for buildin datasets

* Merge V2.0 and pass all unittest

* Fix (template configs)

* Refactor (subset): change function names

* Refactor (custom_classes): add subset check

* Filter instance during training by self.CLASSES

* Fix comments

* Raise error when classes is in unsupport type

* Refactor: put call of get_subset_by_classes in custom.py

* Modify test_dataset to pass CI

* Fix custom_classes bug

* rename clean_data_infos to subset_data_infos

* rename api

* Refactor (APIs): rename imgs_per_gpu to samples_per_gpu

* Clean files

* Refactor (infos): rename self.infos to self.data_infos

* Refactor (all): all category -1 in anchor/bbox head and anchor/bbox target assign

* Fix (datasets): remove label + 1 in datasets

* Fix (bbox_head): fix bug of fc_cls that forget + 1

* Fix (atss_head & free_anchor): fix cat -1 bugs

* Fix (mask_head): remove label + 1 in mask heads

* fix atss

* Fix (rpn): fix cross_entropy_loss bug of RPN

* Fix (anchor_head): fix typo

* Refactor (anchor_head): use background_label rather than num_classes to indicate background class

* Refactor (docstring): add and reformat docstrings

* fix mask iou head

* Fix (mask_head): fix cat -1 bug

* Fix (mask_head): fix bug in mask inference

* Add (tests): add tests for mask rcnn and mask heads

* Refactor (unittest): refactor test_forward

* Refactor (new_empty): use new_full rather than new_empty

* Refactor (background_label): check background_label

* Add TODO

* Refactor (unittest): allow BP in unittest

Co-authored-by: Cao Yuhang <yhcao6@gmail.com>

* Refactor (all): change coordinate system

* Fix (mask_head): fix cat -1 bug in mask_paste

* Fix (unittest)
: modify unittest and pass CI

* reformat to pass CI

* Fix round coordinates bugs

* clean file

* Fix (test): use cpu version of aligned roi_align in tests

* Refactor (mask): clean np.stack

* Refactor (head): reformat code and fix missing -1

* Reformat: reformat and add doc strings

* Refactor (mask_head): more clea docstring

* Modify the code casting digit string as int to convert to float and then to int

* Add Comment: Coordinates may be float type

* Fix: Indentation Error

* use registry to manage datasets

* bug fix for concat dataset

* update documentation to fit the new api

* Add support of the wider face dataset

* Update readme

* Prevent ignoring boxes in test mode

* Rename wider to wider_face

* Rename configs for wider face