* merge legacy to fluid

* Remove legacy code

* Remove legacy code

* Remove DataType test

* Using Tensor directly instead of using EagerTensor

* support gradient_accumulation

* make test_imperative_lod_tensor_to_selected_rows longer

* make test_imperative_lod_tensor_to_selected_rows longer

* open header for custom kernel

* add core utils

* tidy core code

* tify header

* tidy include

* tidy namespace

* resolve conflit

* fix unittest and coverage

* remove platform using

* resolve conflict

* resolve conflict

* fix digamma namespace error

* fix xpu full kernel error

* fix xpu full kernel error

* polish details

* add place for lib storage

* transfer: string tinyformat errors and part of enforce into pten

* remove comment

* fix by code review

* assert is not compile in -DNDEBUG

* add string as dependences of paddle_inference

* updates callers, test=develop

* updates tensor, test=develop

* fixes errors, test=develop

* remove some dtypes, test=develop

* fix errors in the base storage modification, test=develop

* fixes a bug, test=develop

* fixes the bugs in push the whole, test=develop

* updates, test=develop

* update

* update, test=develop

* fixes the mac-py3 CI, test=develop

* remove the storage impl, test=develop

* updates some codes, test=develop

* update, test=develop

* updates pten allocation, test=develop

* Migrate Dim and DDim from paddle::framework into pten namespace

* fix paddle::framework::Array

* fix framework::Array

* Migrate bfloat16/float16/complex from platform into pten::common

* fix typo

* fix code style

* remove offset in storage

* revert api change

* fix custom op slice bug

* fix mutable_data error

* support more eager tensor api

* support multiple constructor for eager tensor

* add place related code

* polish code

* specific randint with dtype of int64

* Support pure cpu test

* refine test in pure cpu

* refine test in pure cpu

* add code-gen file

* add api-gen in cmake

* adjust the code format

* temp save the code

* add genen-api module into pten

* merge the develop code

* fix merge conflict

* fix code conflict with develop

* support reduce_mean/sum

* fix the CI requirement

* fix requirement problem of CI

* remove original api code

* fix bug caused by removing original api

* add scalar and scalar_array

* remove DenseTensor include from Scalar and ScalarArray

* remove inner header from scalar_array

* refactor the method of fill_constant and add some comment

* standarded unittest namespace

* fix detail error

* rename to api to copy_to

* support cast method for tensor

* fix compile failed

* add copy_to and to method for Tensor

* polish msg format

* fix details error

* fix copy_to test compile failed

* fix typo

* add reshape method for Tensor

* fix typo

* fix typo

* fix conflit with develop

* add slice api impl of Tensor

* fix test slice error

* move extension into pten [no-verify]

* append tensor methods by ext_tensor [no-verify]

* append other tensor methods [no-verify]

* ext related files tidy [no-verify]

* include relation tidy [no-verify]

* add pten tensor test [no-verify]

* replace tensor in custom op & compile success

* refine tensor constructor for unittest

* custom relu jit run success

* fix all custom op unittests

* add inference cmake adapt [no-verify]

* fix failed unittests

* fix windows failed unittests

* try to fix kunlun and inference failed

* fix test_elementwise_api error

* try to fix win compile failed

* fix kunlun fp16 type error

* remove useless haddle error macro

* add custom linear op test

* fix compile failed & add win symbols

* fix non pten kernel cast failed

* add dll decl for api

* polish several deetails

* polish details by review comment

* add dll_decl for register