and optimize the c++ implmentation of empty op as PR#26659 reviews,
and add bool for shape op.

* support load infer model format state dict

* add unittests

* remove keep name table

* recolve circle inport

* fix compatible problem

* recover unittest

* polish doc and comment

* add summary for hapi

* Move hapi form paddle/incubate to paddle

* Remove vision/datasets/utils.py and clean code

* Add sample code for conll05

* Print pull path when saving model

* Fix sample code after paramter_list of SGD is changed to parameters

* Fix bug in wmt16 datase

* add dygraph parallel run interface

* polish implement & unified env property name

* add print config arg

* refactor init_parallel_env function

* Compatible with multiprocessing and launch modes

* set default trainer start port

* support run in python 2

* polish python2 support code

* remove python2 support

* refine launch import

* polish dome design details

* refactor api implemention & path

* use new method _set_expected_place

* add spawn unittest framework & mnist test

* add more unittests & doc

* fix unittest failed

* polish english doc

* self review and polish details

* refactor code by reviewer's comments

* fix unittest failed

* fix parallel_env unittest

* fix several typos

* fix error introduced when fixing typos

* add unpublic note for start_processes

* polish details by xiaoguang's comment

* verify correctly when spawn nprocs=-1

* refactor spawn & init_parallel_env design

* polish doc details

* open spawn unittests

* try to fix doc compile error

* try to fix unknown doc format error

* add skip unittest when not gpu

* update the demo code and the doc of varbase.backward.

* update the doc of the fake interface `paddle.fluid.Variable`.

* remove BackwardStrategy.

As the title

add the isnan, isfinite, isinf api for the paddle 2.0

* add bernoulli op

* fix cuda kernel and add unit test

* refine doc

* fix uniform

* Rename uniform and gaussian APIs

* rename uniform_random API as uniform

* Fixed unittest

* fixed unittest AttributeError

* Fixed unittest

* Add uniform function rather than alias

* remove templatedoc

* solve conflict and fix doc code

* fix doc code

* binding tensor method

* binding tensor method

* binding tensor method

* Binding methods for class Tensor and Variable

* Update `paddle.clamp`

rename to `paddle.clip`
add fast path for dygraph mode
remove `out`
rename `input` -> `x`
update doc sample

* Fix leftover `Variable` wording

* Indent doc with spaces

* Remove `:alias` in docs

* Update `enable_imperative` -> `disable_static`

* Remove `imperative`

also trigger CI

* Update tests for better coverage

* Rebase to fix `cosine_similarity`

* Fix `cosine_similarity` some more

* fixed static module

* solve conflict

* Add Distribution base class, Uniform class and Normal class

* release Distribution class and Normal, Uniform class

* Add Doc args explaination

* save distributions.py and process in distribution.py

* delete useless function in test_distribution

* Add NormalNumpy test class

* Add probs in NormalNumpy

* add distribution to paddle init

* Add Distribution base class and name attribute unittest

* Change Doc

* Change Doc

* adjust format

* Fixed Doc Code

* implement probs and change Variable to Tensor

* Add name for all functions and add name unittest

* support int datatype

* Add dynamic mode

* optimize test_distribution static and dygraph

* Add new API: paddle.prod

test=develop

align expand_as op to expand.

* add set/get default dtype

* expose and unify the Tensor concepts to the user

* expose tensor to user

* add copy place for Tensor

* add copy place for Tensor

* add note

* add macro PADDLE_WITH_CUDA

* remove RUN_TYPE=DIST

* fix some error

* add tile_op, test=develop

* Upgrade `no_grad` decorator

test=develop

- match torch decorator usage (i.e., with parenthesis)
- handle generator functions
- add `paddle.no_grad` alias

* Switch from `functools` to `decorator`

preserves signature

* Reword decorator usage note

* fixed static module

* solve conflict

* remove original name for alias API

* move paddle.fleet to paddle.distributed.fleet

* Add the max, min, maximum, minimum api for the API 2.0, test=develop

* Directory migration, test=develop

* Change imperative from paddle init to paddle framework, test=develop

* Fixed jit bug, test=develop

* default static mode, test=develop

* fixed format and create parameter belongs to framework, test=develop

* Fixed import package, test=develop

* fix __init__ format, test=develop

* fixed alias problem

* fixed paddle.enable_imperative problems, test=develop

* Add unittest

* delete install_check comment

* Fixed unittest timeout

* fixed unittest error

* move Program default_xx_program to static package

* optimize unittest method

* fixed framework __init__ format

* fixed jit path

* delete alias

* move jit to paddle

* Fixed unittest format

* fixed paddle.default_main_program

* Fixed save load API in paddle __init__.py

* fixed ci paddle.imperative.to_variable

Update the code for the compare_ops, update the api and doc 

* New features, add sinh and cosh op, test=develop

* remove duplicate test function and remove out paramters, test=develop

* Add out paramters temporary, remove later. test=develop

* remove out args, PR 25570, test=develop

* remove TestParameter, test=developx

* add test api for static dygraph, test=develop

* add backword unittests for sinh and cosh, test=develop

* add op multiply, delete op elementwise_mul from math.py. test=develop,test=document_fix

* bug fix. test=develop,test=document_fix

* bug fix. test=develop,test=document_fix

* bug fix. test=develop,test=document_fix

* bug fix. test=develop,test=document_fix

* add unittest for multiply op. test=develop.

* fix code style. test=develop

* use random input. test=develop

* add test error case for static computation graph. test=develop

* add np.random.seed(7)

* increase input ndarray size. test=develop

* change float32 to float64. test=develop

* delete mul op. test=develop,test=document_fix

* bug fix. test=develop,test=document_fix

According to paddle 2.0 standard
1, change flip api attr name 'dim' to 'axis'.
2, support empty axis
3, change example code to imperative mode.