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

* [Refactor]: modify interface of Visualizer.add_datasample (#365)

* [Refactor] Refactor data flow: refine `data_preprocessor`. (#359)

* refine data_preprocessor

* remove unused BATCH_DATA alias

* Fix type hints

* rename move_data to cast_data

* [Refactor] Refactor data flow: collate data in `collate_fn` of `DataLoader`  (#323)

* acollate data in dataloader

* fix docstring

* refine comment

* fix as comment

* refactor default collate and psedo collate

* foramt test file

* fix docstring

* fix as comment

* rename elem to data_item

* minor fix

* fix as comment

* [Refactor] Refactor data flow: `data_batch` argument of `Evaluator.process is a `dict` (#360)

* refine evaluator and metric

* compatible with new default collate

* replace default collate with pseudo

* Handle data_batch in metric

* fix unit test

* fix unit test

* fix unit test

* minor refine

* make data_batch optional

make data_batch optional

* rename outputs to predictions

* fix ut

* rename predictions to outputs

* fix docstring

* fix docstring

* fix unit test

* make outputs and data_batch to kwargs

* fix unit test

* keep signature of metric

* fix ut

* rename pred_sample arguments to data_sample(Visualizer)

* fix loop and ut

* [refactor]: Refactor model dataflow (#398)

* [Refactor] Refactor data flow: refine `data_preprocessor`. (#359)

* refine data_preprocessor

* remove unused BATCH_DATA alias

* Fix type hints

* rename move_data to cast_data

* refactor model data flow

tmp_commt

tmp commit

* make val_cfg and test_cfg optional

* roll back runner

* pass test mmdet

* fix as comment

fix as comment

fix ci in DataPreprocessor

* fix ut

* fix ut

* fix rebase main

* [Fix]: Fix test val ddp (#462)

* [Fix] Fix docstring and type hint of data flow (#463)

* Fix docstring of data flow

* change signature of hook

* fix unit test

* resolve conflicts

* fix lint

* Rename data to structure

* adjust the way to import module

* adjust the way to import module

* rename Structure to Data Structures in docs api

* rename structure to structures

* support using some modules of mmengine without torch

* fix circleci config

* fix circleci config

* fix registry ut

* minor fix

* move init method from model/utils to model/weight_init.py

* move init method from model/utils to model/weight_init.py

* move sync_bn to model

* move functions depending on torch to dl_utils

* format import

* fix logging ut

* add weight init in model/__init__.py

* move get_config and get_model to mmengine/hub

* move log_processor.py to mmengine/runner

* fix ut

* Add TimeCounter in dl_utils/__init__.py

* [Refactor] Refactor the import rule

* minor refinement

* add a comment

* Move the design of hook to design/hook.md

* add relative links in docs

* update docstring of hooks

* refine checkpointhook docs

* refine

* fix comments

* refine

* add logging.md link in hook.md

* resolve comments

* fix typo

[Visualizer] use FigureManager to manage figure to avoid affecting plt.show() outside Visualizer(#440)

* figure in Visualizer is not managed by plt

* encapsulate code and remove unused code