* fix loss mean

* update

* Add smddp dist backend option

* [Dev]: Upgrade pre commit hooks (#576)

* Upgrade the versions of pre-commit-hooks

* update zh-cn.yaml

* [Docs] Fix the docstring of model sub-package (#573)

* [Doc]: Update config.md (#562)

* Update config.md

* Update config.md

* [Doc] delete the error comment  in docs (#514)

Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>
Co-authored-by: Zhengfei-0311 <78833899+Zhengfei-0311@users.noreply.github.com>
Co-authored-by: vansin <msnode@163.com>

* Upgrade the versions of pre-commit-hooks

* update zh-cn.yaml

* [Refactor] Refactor fileio but without breaking bc

* handle compatibility

* fix format

* modify io functions

* fix ut

* fix ut

* rename method names

* refine

* refine docstring

* fix ut in windows

* update ut

* minor fix

* ensure client is not None when closing it

* add more examples for list_dir_or_file interface

* refine docstring

* refine deprecated info

* fix ut

* add a description for lmdb docstring

* [Fix] Support compare numpy array dataset meta

* Add comment

Remove unnecessary "if statement".

* [Feature] Support convert BN to SyncBN by config

* make unit test compatible with cpu

* Fix as comment

* fix unit test

* change signature of convert_sync_batchnorm: rename sync_bn to implemention

* fix unit test

* fix unit test

* fix merge ci

* make timeout larger

* fix ema load_state_dict

* fix ema load_state_dict

* fix for test

* fix by review

* fix resume and keys

* wandb define_metric

* fix docs

* add wandb docs link

* bugfix wandb image

* del judged

* use self._wandb

* fix unit test install mmdet and mmcls

* raise error when mmdet is not installed

* rename check_and_install to install_package

* split test case

Co-authored-by: C1rN09 <zhaoqian@pjlab.org.cn>

* structure tutorials

* refine data element docs

* modify introduce

* fix comment

* fix comment

* fix comment

* tmp commit

* refine docstring

* minor refine

* fix as comment

* add tutorial for merge_from_dict

* minor refine

* minor refine

* export md by jupyter

* temp add ipnb

* refine the docs

* remote ipynb

* fix as comment

* add change _base_.variable

* Fix as comment

* minor refine

* Fix as comment

* Fix as comment

* minor refine

* add testing utils

* fix ut

* add blank line betweeen `Args` and `Returns`

* [CI] Full tests

* Add github tests

* fix

* fix typo

Co-authored-by: zhouzaida <zhouzaida@163.com>

* [Docs] Refine registry docs

* explain how to use _scope_

* refine

* regist pytorch ddp and dp, add unit test

* minor refine

* Support check custom wrapper

* enhance ut

* add args to OptimWrapper.step backward zero_grad

* minor refine

* minor refine

* [Fix] Fix EMAHook trigger train loop init during testing.

* fix sync buffer

* update ut

* fix sync buffer

* fix sync buffer

* add set random seed fun

* fix conflict

* allign the previous version