* [Docs] Add readthedocs.yml

* include torch in readthedocs.yml

* add torch torchvision in docs.txt

* [WIP] Refactor-docs-structure

* [Docs] Check link and fix rst  (#498)

* check link

* fix rst

* Fix conf.py

* Fix lint

* minor refine

* minor refine

* modify zh_readme and index.rst

* add migration exampls get_started design to en

* add tutorials to en

* correct chinese doc link

* Apply suggestions from code review

* Update docs/en/advanced_tutorials/distributed.md

Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>

Co-authored-by: Mashiro <57566630+HAOCHENYE@users.noreply.github.com>

* [Docs] Make API of docs clearer

* minor fix

* fix md format

* Add Visualizer tutorials

* Add Visualizer designs

* update

* update

* update

* fix commit

* add demo image

* simplify code according to #440 and add some results picture

* replace image url

* update

Co-authored-by: liukuikun <liukuikun@sensetime.com>

* 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

* Add profiling tools

* fix docstr

* fix docstr

* update

* fix bug

* update

* update

* fix error

* fix mypy

* uodate

* merge main

* fix UT

* Add pyupgrade pre-commit hook

* fix ut

* remove comments

* [Feature] Add Runner and Loop

* refine docstring

* refine docstring

* refine __init__ of Runner

* add Runner.save_checkpoint

* add comment for data_batch

* rename validation_cfg to val_cfg

* update branch

* update branch

* discard wear reference

* set seed for torch in dataloader worker

* refine comments

* reorder methods

* import module in __init__.py

* add runner.load_checkpoint

* rename attributes

* fix indent

* fix indent

* add comment for LOOPS

* add example for methods

* add example for methods

* refine examples

* add Runner.resume and refactor register_hooks

* remove type hint of runner in CheckpointHook

* rename before_run to before_train

* remove collate

* add before_run after_run for loop.run

* dummy collate_fn

* add more unit tests

* move call_hook('before_run') to runner

* minor fix

* add comments for collate_fn

* fix type hint

* refactor logic to load or resume checkpoint

* fix typo

* add comments for IterBasedTrainLoop

* refactor unit tests

* fix unit tests

* refactor

* fix setup_env

* refine

* minor fix

* Merge branch 'main' of github.com:open-mmlab/mmengine into zzd/add-runner

* minor fix

* minor fix

* refine

* refactor unit tests

* fix unit tests

* add launcher property

* add logger, message_hub and writer unit tests

* add cur_dataloader attribute for runner

* fix IterBasedTrainLoop

* add torch.no_grad decorator

* add master_only decorator for save_checkpoint

* add before_test_epoch in TestLoop

* refactor load_or_resume method

* refine docstring

* fix typo

* build_dataloader can handle dataset object

* add dump_config for runner

* collate_fn should not a lambda function

* minor fix

* refine docstring

* fix unit tests

* improve comments

* refine unit tests

* rename collate_fn to pseduo_collate

* add 'TODO' tag

* [WIP] Visualizer

* add draw featmap

* update docstring

* update docstring

* update docstring

* fix comment

* fix comment

* fix comment

* fix comment

* fix comment

* [Feature] Add distributed module

* fix IS_DIST error

* all_reduce_dict does operations in-place

* support 'mean' operation

* provide local group process

* add tmpdir argument for collect_results

* add unit tests

* refactor unit tests

* simplify steps to create multiple processes

* minor fix

* describe the different of *gather* in mmengine and pytorch

* minor fix

* add unit tests for nccl

* test nccl backend in multiple gpu

* add get_default_group function to handle different torch versions

* minor fix

* [Feature] Add distributed module

* fix IS_DIST error

* all_reduce_dict does operations in-place

* support 'mean' operation

* provide local group process

* add tmpdir argument for collect_results

* add unit tests

* refactor unit tests

* simplify steps to create multiple processes

* minor fix

* describe the different of *gather* in mmengine and pytorch

* minor fix

* add unit tests for nccl

* test nccl backend in multiple gpu

* add get_default_group function to handle different torch versions

* minor fix

* minor fix

* handle torch1.5

* handle torch1.5

* minor fix

* fix typo

* refactor unit tests

* nccl does not support gather and gather_object

* fix gather

* fix collect_results_cpu

* fix collect_results and refactor unit tests

* fix collect_results unit tests

* handle torch.cat in torch1.5

* refine docstring

* refine docstring

* fix comments

* fix comments

* Add DefaultSampler and InfiniteSampler

* Add unit test

* Add samplers to API reference

* Update docstring

* Improve according to comments

* Rename `num_replicas` to `world_size`

* Update docstring.

* Update mmengine/data/sampler.py

Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>

* Update mmengine/data/sampler.py

Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>

* Fix typo in unit test

Co-authored-by: Wenwei Zhang <40779233+ZwwWayne@users.noreply.github.com>
Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>

* [Docs] Configure the documentation

* fix the format

* introduce the usage of default_scope

* add Chinese documentation

* move docs configure to another pr

* clean pr

* refactor registry docs

* fix typo

* fix typo

* reorg

* add more examples

* reslove comments

* reslove comments

* reslove comments

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

* [Docs] Configure the documentation

* delete mypy.ini