* remove datasets.loader and add datasets.samplers

* fix typo in the filename

* Merge _dist_train and _non_dist_train

* Add missing distributed arg to Fp16OptimizerHook

* Add ability to specify device ids for non-distributed training

Changes to be committed:
modified:   mmdet/apis/train.py
modified:   tools/train.py

* Deprecate cfg.gpus in favor of cfg.gpu_ids

Changes to be committed:
modified:   mmdet/apis/train.py
modified:   tools/train.py

* Fix strange issue with mutually_exclusive_group

Changes to be committed:
modified:   tools/train.py

* Fix gpu-ids nargs parameter

Changes to be committed:
modified:   tools/train.py

* Refactor (resnet.py): remove unnecessary initialization of dcn

* change key names

* add merge conv bn

* fix wrong push

* support save merged model

* rename merge to fuse, add annotations

* fix typos

* 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

* Fix (flip): not setting default values of flip during loading

* Fix (loading): correct the format of default img_norm_cfg

* add condition on RoIPool backward

* format

* delete space

* reformat

* add newline end of file

* Fix bug: index out of range when num_extra < len(indice)

* Unified img_metas api

* minor fix

* fix typo

* update images for async test

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

* Add class to wrap result fields into lists for evaluation

On branch wrap_into_lists
Changes to be committed:
modified:   mmdet/datasets/pipelines/formating.py

* Add doctsring to WrapFieldsToLists

On branch wrap_into_lists
Changes to be committed:
modified:   mmdet/datasets/pipelines/formating.py

* update the example in docstring of WrapFieldsToLists

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

* fix bug of mse_loss

* reformat

* use single quote

Co-authored-by: penghaozhou <penghaozhou@tencent.com>
Co-authored-by: wwzhang <wayne.zw@outlook.com>

On branch load_multichannel
Changes to be committed:
modified:   mmdet/datasets/pipelines/loading.py

* fix dcn when input size smaller than kernel size

* update

In example 4:

Test Mask R-CNN on COCO test-dev with 8 GPUs, and generate the json file to be submit to the official evaluation server.
./tools/dist_test.sh configs/mask_rcnn_r50_fpn_1x.py
checkpoints/mask_rcnn_r50_fpn_1x_20181010-069fa190.pth
8 --format-only --options "jsonfile_prefix=./mask_rcnn_test-dev_results"

where --format-only should be --format_only

* Set initial values for default meta keys when loading images

On branch set_default_metakeys
Changes to be committed:
modified:   mmdet/datasets/pipelines/loading.py

* Change local variable name

On branch set_default_metakeys
Changes to be committed:
modified:   mmdet/datasets/pipelines/loading.py

On branch list_to_kvaction
Changes to be committed:
modified:   tools/test.py

* fix (transforms): fix bugs in transforms when the gt is empty

* Fix (SSD): fix bug of data pipeline used in SSD, test more pipelines

* Fix (test_config): move print for more clear debug info

* clean comments

* add onnx convert script

* upload pytorch2onnx.py

* restore config

* set use_torchvion on-the-fly, update doc

* update doc

* support pass input

* fixed passes

* add batched nms

* fix soft_nms bug

* fix atss uint8 warning

* fix bool sum error

* Update GETTING_STARTED.md

--- def forward(x):  # should return a tuple
+++ def forward(self, x):  # should return a tuple

* Add browse dataset tool

* Update browser_dataset.py

* Update browser_dataset.py

* Update dataset browser

* Update dataset browser

use `mmcv.imshow_det_bboxes` to show

* Format code by yapf

* Fix show-interval default type to int

* refactor util

* merge common with ops

* Rewrite the code due to License issue.

* Add center sampling

* Fix bug

* Add an extra parameter to control on / off
Resolve the comments

* Add config for `center sampling`

* Rename the config

* Change work_dir

* move arguments and rename variables

* feature (roi_align_v2): use roi_align v2 to support aligned=True

* fix (setup.py): fix install bug

* recover configs to the original ones

* remove cpu version for now

* rename files

* reformat (roi_align): clean code and reformat

* support legacy roi_align

* support legacy roi_align

* reformat (roi_align): reformat c/cuda/python code

* fix reformat request

* add unsaved change

* pass yapf

* merge roi_align function

* update note

Co-authored-by: beansi <zhangwenwei@sensetime.com>

* Allow find_unused_parameters to be set in config

* Fix typo

* Fix wrong keyword argument 'nms_cfg' in htc

* fix the bug of simple_test with proposals
remove the redundant codes in fast_rcnn

* correct the wrong comment

* minor update

* fix typos

* update fast test pipeline

* fix yapf error

* change fields from tuple to list

Co-authored-by: wangchuanyuan <Trayvon@wangchuanyuandeMacBook.local>
Co-authored-by: Cao Yuhang <yhcao6@gmail.com>

* fix (dcn): fix config bugs and group bugs of dcn

* keep groups in backbone rather than in dcn configs

* fix (htc dcn): rm groups in htc dcn config