* add index sample fp16 support

* remove fluid APIs in distributed_strategy.py and role_maker.py

* Revert "remove fluid APIs in distributed_strategy.py and role_maker.py"

This reverts commit 223bbee990d3bf69e252fc3c0f19e3873550a264.

* remove fluid APIs in distributed_strategy.py and role_maker.py

* remove index sample op changes

* remove fluid APIs under fleet.base

* remove fluid APIs under fleet.layers.mpu

* remove fluid APIs under fleet.meta_optimizers

* fix fluid error

* fix util_factory.py

* reset fluid.io.load_inference_model API

* remove dygraph.parallel.prepare_context

* remove fluid.dygraph.StaticModelRunner API

* remove split_lod_tensor merge_lod_tensor

* remove unittests

* isort all files

* revert conflicting files

* revert conflicting files

* revert conflicting files

* revert conflicting files

* revert conflicting files

* [remove fluid] under fleet meta_optimizers

* [remove fluid] under fleet meta_optimizers

* [remove fluid] under fleet meta_optimizers

* [remove fluid] under fleet meta_optimizers

* [remove fluid] under fleet meta_optimizers

* [remove fluid] under fleet meta_optimizers

* [remove fluid] under fleet meta_optimizers

* [remove fluid] under fleet meta_optimizers

* [remove fluid] under fleet meta_optimizers

* [remove fluid] under fleet meta_optimizers

* [remove fluid] under fleet meta_optimizers

* [remove fluid] under fleet meta_optimizers

* [CodeStyle][py2][U004] unecessary explicit `object` inheritance in class definition

* fix an increment

* [CodeStyle][E712] use `if cond`/`if cond is True` for comparison with `True`

* revert changes in fluid

* revert unrelated file

* revert changes in norm

* revert changes in auto_parallel_amp

* fix norm and auto_parallel_amp

* revert a typo fix due to fixed at #47477

* update config

* re-blacken python code

* temporarily disable date and diff_py_file

* skip a format

* skip ReplaceAllReduceOp in GraphtoBlock when nccl_ctxs_ is nullptr

* update ut

* test_dist_allreduce_op failed

* fix test_dist_allreduce_op

* add ut

* fix nccl cpu compile

* fix

* [CodeStyle] remove all future import

* revert test_error.py

* restore future import in example code

* [MLU] fix sync_bn of mlu and add unittests

* [MLU] remove redunant code of pytest

* use tempfile to place temporary files

* update

* revert test_communicator

* fix test_dist_base

* use yapf to format all python file

* yapf exclude two unittests file for they rely on writing and reading file, and format will break them

* disable diff_py_file because too many diff files cause command following failed

* support diff batch for sparse of eagerreducer

* fix

* support process group in dp with fleet api

* update

* fix uts

* update

* add uts for EagerReducer

* add more uts

* fix bugs

* fix bugs

* modify

* modify uts

* fix bugs

* update

* update

* update

* solve conflicts and merge

* add some other uts

* modify time of uts

* update

* update

* update

* remove uts of resnet

* Added HCCL backend support in dynamic graph mode

* fix segmentation fault

* add ut

* In cpu parallel using gloo, add various length support for SelectedRows

* fix bug

* fix bugs

* fix by code review

* remove timeout

* mv recv to head, test=develop

* del py2 code2

* fix test timeout

* fix find_unused_parameters default value

* support control flow

* supoort sync_parameters_buffers

* fix the bug of sparse embedding

* update, test=develop

* remove data parallel scale loss & apply collective_grads

* move apply in minimize

* fix failed unittests

* add gloo initializer, test=develop