* fluid clean: remove print/switch from fluid to static

* remove Switch in static.__init__

* fix conflicts.

* replace Switch by case.

* fix piecewise_lr decay.

* fix typo

* fix conflicts.

* fix lr dtype

* keep Switch in paddle.static.nn.control_flow and fix piecewise_lr.

* fix conflicts.

* keep Switch in the fluid.

* fix Switch doc

* fix example in Switch doc

* fix Switch doc.

* fix static/__init__.

* delete old dygraph op test

* remove fluid.data

* fix typro

* fix somme unitest error

* fix conflicts

* fix sample code error

* fxi sample coder error

* fxi sample code error

* fxi sample code error

* fix xpu test error

* fix xpu test error

* Delete ps_pb2.py

* fix test error

* fix typro

* fix sample code error

* fix comments

* fix test norm op data

* fix sample code error

* fix conflicts

* migrate fill_constant to paddle.tensor

* move fill_constant to paddle.tensor and repalce the reference

* add missing fill_constant replacement

* fix typro

* remove unused import fill_constant

* fix zeros import error

* fix circle import

* fix layers.zeros

* fix unitest

* fix unitests

* fix unitest

* use paddle.full replace fill_constant in samplecode

* fix sample code

* recovery xpu test

* recovery xpu test

* fix circle import

* fix utils import error

* fix utils error

* fix circle import

* redo

* fix circle import

* fix prim fill constant import

* fix type error

* fix increase error

* fix test error

* fix fill_constant

* move fluid.utils to paddle.utils.layers_utils

* fix error

* delete original fluid layers utils

* remove import and old utils

* remove more old utils import

* change import path of fill_constant in the layers_utils.py

* fix mistake

* fix error

* expose in __init__.py

* for comment

* when change the ref of func is_sequence, it should change to the root of is_sequence instead

* for codecheck

* replace paddle.fluid.layers.data and remove io.data

* partial commit

* partial commit

* partial commit

* partial commit

* partial commit

* partial commit

* remove data in fluid.layers.io.__all__

* fix errors

* fix unitests

* fix unitest

* fix unitests

* fix unitest

* fix unitest

* fix unitests

* fix unitest

* fix test_layers unitests

* fix typro

* fix unitest

* fix unitest

* fix unitest

* fix typro

* fix unitest test_model_cast_to_bf16

* fix test_reducescatter

* fix collective unitest

* fix collective unitests

* fix collective unitests

* add coverage

* fix add layers.data

* re run ci

* fix some typro

* fix samplecode error

* fix samplecode error

* [Eager] polish some apis logic

* polish api logic

* move fc from fluid to paddle2.0

* fix unit test

* fix some examples

* fix some examples

* rm legacy layers part6

* rm non_static_mode

* modify non_static

* minor change

* rm loss

* rm in_legacy part8

* minor change

* 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

* Update docstring:
1. 去除 python/paddle/tensor/manipulation.py 中 cast 函数描述中的 This OP；
2. 调整 python/paddle/fluid/layers/control_flow.py 中 Print 函数中参数描述的顺序，添加 optional 描述；
3. 为 python/paddle/tensor/logic.py 中 logical_and 函数添加 optional 描述；
4. 为 python/paddle/fluid/reader.py 中 DataLoader 类中 from_generator、from_dataset 函数添加 optional 描述；
5. 在 python/paddle/fluid/layers/nn.py 中 crf_decoding 函数的 param_attr 在使用中确实可视为存在默认值 None，故添加 optional 描述；
6. 修复 python/paddle/static/nn/common.py 中 data_norm 函数描述里 tex 语法错误的问题，并一并修复同一文件中的相同问题。

* 根据 review 意见修改部分内容。

* 将谓语动词去掉第三人称单数形式。

* 同步中文文档变更。

* string-->str; test=document_fix
Co-authored-by: NLigoml <39876205+Ligoml@users.noreply.github.com>

* del array_write & array_read

* fix import err

* fix import err

* fix example codes

* Merge branch 'reduce_sum' of https://github.com/GhostScreaming/Paddle into mine_fluid_clean_common.

* Fix some bugs.

* Clean APIs in python/paddle/fluid/layers/control_flow.py

* Polish code style.

* Change API.

* Fix some bugs.

* Fix some bugs.

* refactor: rm shrink_memory

* refactor: rm create_array

* refactor: rm array_length

* [Fluid Clean]Migrate utils files and delete dygraph_to_static dir

* fix setup.py.in

* fix import

* fix unittest

* fix code style

* fix unittest

* [Fluid Clean]Migrate if/while/return/break transformer into paddle.jit

* migrate call_transformer

* migrate call_transformer

* remove lod_tensor_to_array, array_to_lod_tensor, DynamicRNN

* remove less_equal, greater_than, greater_equal, equal, not_equal

* remove fluid.reduce_sum

* remove fluid.reduce_sum

* modify axis and import paddle

* modify keepdim and out_name

* modift unittest

* modift unittest

* modify CI_static and loss.py

* modify test_mse_loss

* modify static ci

* modify static ci datatype

* add import paddle in test

* fix conflict

* fix conflict

* modify ci

* modify ci

* fix_conflict

* fix bug

* code_style

* remove transpose

* codestyle check

* modify CI_STATIC

* modify CI_STATIC

* modify enable static()

* remove unused import

* fix conflict about stack

* fix conflict about stack

* fix conflict about stack

* endless conflict

* remove apis in fluid.ops

* fix test_activation_nn_grad

* fix circle import error

* fix ops

* fix cos

* fix divide not inplace

* remove lazy-import part

* standard api

* fix sparse bugs

* fix xpu bugs, test=kunlun

* remove hard code for custom unittest

* open ci, test=kunlun

* deal with conflict

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

* fix an increment

* [CodeStyle][py2][U008] remove unnecessary args in `super()`

* remove remained args

* revert changes in test_pylayer_op

* Revert "revert changes in test_pylayer_op"

This reverts commit ff185a9ae738afac3b0264f61bde6c6b7f72e7c4.

* revert some changes in example code

* [CodeStyle][E711] use `is`/`is not` for comparison with `None`

* `self.assertTrue($A is None)` -> `self.assertIsNone($A)`

* `self.assertTrue($A is not None)` -> `self.assertIsNotNone($A)`

* `self.assertFalse($A is None)` -> `self.assertIsNotNone($A)`

* `self.assertEqual($A, None)` -> `self.assertIsNone($A)`

* `self.assertNotEqual($A, None)` -> `self.assertIsNotNone($A)`

* fix typo `Fasle`/`Flase` -> `Flase`

* fix typo `Ture` -> `True`

* [CodeStyle][py2] remove `paddle.compat`

* remove compat from `paddle.__init__`

* enable_static in sample code

* Revert "enable_static in sample code"

This reverts commit ffccaa633900154ea5f3d056e746aae9a1927399.

* enable_static in sample code

* fix bugs while cond receives dict as input

* add unittest

* change flatten -> _is_sequence_except_dict

* update config

* re-blacken python code

* temporarily disable date and diff_py_file

* skip a format

* [CodeStyle][py2] remove `compat` module (to_text)

* remove some unnecessary decode

* remove to_text definition and unittest

* Revert "remove to_text definition and unittest"

This reverts commit a6b69cb8dca8b9b031ce10ea32d1040e7e0dd267.

* remove an assertion

* empty commit