* move DeviceContextPool to phi

* add EmplaceExternalContextFunc

* update namespace

* update cmake

* fix bugs and create context_pool_impl.h

* replace platform::is_xxx_place

* fix bugs

* update generator

* fix bugs

* fix bugs

* fix bugs

* fix bugs

* fix bugs

* fix bugs

* fix bugs

* fix enforce usage

* Revert "fix enforce usage"

This reverts commit 5f521f08a69713cee506e64a00ec6d9fba709e27.

* fix bugs

* rm XPUDeviceContext and CustomDeviceContext

* fix bugs

* fix fix context init bug

* fix bugs after merge

* fix bugs

* fix name

* fix mutable_data

* update and fix bugs

* fix bugs

* update

* fix bugs

* fix name

* fix bugs

* merge

* fix bugs

* create context_pool in phi/backends

* create context_pool in phi/backends

* fix bugs

* fix xpu bugs

* fix rocm bugs

* fix bugs

* fix bugs

* fix bugs

* fix xpu bugs

* update

* update

* fix bugs

* fix bugs

* rename elementwise_heaviside to heaviside

* delete __init__.py

* fix bug

* delete axis of fmin

* fix bug

* Replace mutable_data with DeviceContext.Alloc in phi kernels

* Fix CI errors

* Fix CI errors

* Fix CI errors, test=kunlun

* Fix CI errors, test=kunlun

* Handle rnn_functor

* Update approvals

* [Eager] Fix paddle.grad interface

* [Eager] Support minimum SubGraph for GeneralGrad

* Add needed_nodes to prune grad graph more thoroughly

* [Eager] Add grad_node_trans_mapping_ to record which grad_node has been transformed to AccumulationNode

* [Eager] Fix paddle.grad interface

* Polish code

* remove potential_stop_node

* Add endding_nodes to enhance genSugraph logic

* clear endding_nodes_

* polish code

* rename endding_nodes to endding_nades_

* Refactor grad interface

* Add register_hook case to fix coverage-ci

* Fix code format

* Refactor general_grad

* Add more code comments

* call clear directly to release GradSlotMeta

* fix a mistake

* fix matmul/ multiply kernel logic and optional input in yaml, fill zeros logic and so on.

* fix batch_norm_double_grad yaml optional config

* fix tanh_triple_grad yaml and kernels

* fix MultiplyTripleGradKernel optional logic

* fix merge mistake

* fix compile error

* remove legacy attr for bn

* polish code

* fix some kernel

* merge develop

* fix error

* remote log

* fix kernel with full like

* hide value log behind

* hide value log behind

* fix matmul_triple grad
Co-authored-by: NWeilong Wu <veyron_wu@163.com>

* perfect copy

* deal with conflict

* deal with conflict

* fix compile bugs

* fix unittest bugs

* change code format

* deal with conflict

* modify code by review

* fix ce bugs

* fix ce bugs

* add lo

* perfect code format

* deal with conflicts

* fix starganv2

* fix starganv2 stop_gradient end error

* fix edvr_starganv2

* fix mul kernel to fix optional ddx

* fix typo

* refactor the optional tensor

* remove optiona<MetaTensor> in InferMeta

* fix bug

* fix optional<vector<Tensor>>

* fix bug

* fix rmsprop

* fix amp of eager_gen

* polish code

* fix deleted code

* fix merge conflict

* polish code

* remove is_nullopt_

* fix merge conflict

* fix merge conflict

* change the output format of C++ backward api

* fix merge conflict

* fix sparse api code auto-gen

* fix eager_gen bug

* fix bug of output is null

* fix bug of conv2d_grad_impl

* fix optional grad

* fix bug of eager-gen double_grad

* fix bug

* fix multiply_double_grad bug

* remove node pruning

* Create elementwise_heaviside_op.cc

* add ElementwiseHeavisideFunctor

* Create test_elementwise_heaviside_op.py

* 增加heaviside的python接口

* add heaviside in white list

* 增加heaviside的签名

* 增加heaviside的核函数

* 增加heaviside梯度的核函数

* 增加heaviside梯度的注册

* 调整代码格式

* Update elementwise_sig.cc

* add heaviside in __all__

* Update heaviside docs

* Update math.py

* Update math.py

* Update math.py

Revert "Revert "[Phi] Move elementwise_floordiv and elementwise_pow to phi (#40993)" (#41065)" (#41110)

This reverts commit 3a6f1135.

This reverts commit b532315d.

* mv floordiv to phi

* mv elementwise_pow to phi

* fix as review

* move elementwise_div grad

* change mutable_data to alloc

* fix compile bugs

* move elementwise function to funcs directory

* fix compile bugs

* modify according to comment

* remove SetAllocationForOutputTenosr

* add place param for copy kernel

* recover SetAllocationForOutputTenosr

* polish code

* fix empty_dev api bug

* test=allcases

* test=allcases

* fix bug

* recover empty

* recover modify

* rename pten dir to phi

* rename namespace to phi

* rename infrt pten dir to phi

* resolve conflict

* rename pten to phi in cmake

* revert all infrt change

* change needed files

* fix infrt failed

* fix inference failed

[Pten]Refactor elementwise_add grad / double grad / triple grad Kernel and move them to pten (#39048)

* refactor elementwise add grad

* fix compile bugs

* fix unit test bugs

* fix file conflicts

* fix bugs when buildPtenContext