* change 'math' to 'math_kernel'

* fix compile bugs

* merge develop

* fix compile bugs

* fix compile bugs

* move reduce files by new rule

* add set header

* format code style

* merge develop and fix conflict

* merge develop and fix conflict
Co-authored-by: NYuanRisheng <yuanrisheng@baidu.com>

* change 'math' to 'math_kernel'

* fix compile bugs

* merge develop

* fix compile bugs

* move cpu_impl of elementwise kernel to new directory

* move inner cast api to cast_kernel.h

* resolve conflit

* first commit

* pass ctest of  elementwise_div_grad

* refactor matmul directory in pten

* fix merge conflict

* remove intype arg in cast kernel

* modify conj config in api.yaml by dictionary order

* rm unused code in cast_kernel.cu

* No harm to KP

* Pass the compile stage

* change the WriteData function

* fix template bugs and pass ctest of current elementwise

* for passing partial template specialization of tempalte function in CI-ROCm

* To make 'WriteData' funtion flexible.

* a less harmful way to support multi-output

* a less harmful way to support multi-output

* rename to api to copy_to

* revert needless change

* polish format

* add register general kernel marco

* move copy kernel impl

* revert needless change

* polish details

* fix xpu compil faild

* fix xpu compile failed

* polish format

* combine reduce_cuda codes

* support float16 in pten redcue_mean

* replace ReduceCudaKernel impl with pten reduce impl

* mv reduce funcs into reduce_cuda_impl

* rm unsed codes and headers

* mv GetReduceDim into reduce_cuda_impl

* recover GetReduceDim in reduce_op.h

* add new dispatch macro

* fix pool op output not inited and cause transform to pten::denseTensor error

* fix output tensor not initialized error

* rename new dispatch macro and format code style

* rm reduce_functor_op.h file

* move dot kernel impl

* remove needless cmake items

* rename cuda to gpu

* revert CMake change

* resolve conflit

* rename other cuda to gpu

* poish details

* fix when out_dtype is same with x.dtype and still transform type error

* fix spell error

* add pten conj kernel

* modify conj_kernel file path

* add defined cuda macro to cuda/conj_kernel.h

* fix_bugs_for_elementwise_branch_selection

* fix merge_dims bugs

* fix all influenced file

* unify device context entrance

* move all_context include to header

* polish cmake relay for device_context

* fix npu compile failed

* fix npu compile failed

* add register_ctx_kernel and move scale kernel

* polish details by reviewer comment

* fix xpu compile failed

* fix cmake error

* Reduce reshape kernel functions in pten

* delete notes

* fix bugs when compile

* modify register name

* fix compile bugs

test=document_fix

* fix reduce_max bug

* add unittest

* fix pten::Copy use error in redcue_impl

* remove in_dtype args in reduce kernel

* fix copy error

* fix copy error