* add bn cpu version; test=develop

* move batch norm to pten

* move batch norm to pten; test=develop

* fix bug; test=develop

* fix func::tranpose depend bug; test=develop

* fix compile bugs; test=develop

* fix use_op batch_norm bug; test=develop

* fix cudnn bn add relu test; test=develop

* fix pten context build and double grad bug; test= develop

* remve useless code; test=develop

* add batch norm gpu fp16 support; test=develop

* fix test bn op bug; test=develop

* remove output dtype set; test=develop

* fix bug; test=develop

* fix bug; test=develop

* fix applay pass to program bug; test=develop

* revert to develop; test=develop

* fix rocm bug; test=develop

* revert operator to develop; test=develop

* fix pre_commit; test=develop

* fix statci check error; test=develop

* resolve conflict; test=develop

* ana batch norm bug;

* revert batch norm op

* resolve conlict

* fix nan inf and speed bug; test=develop

* fix bug; test=develop

* fix error; test=develop

* test expand op; test=develop

* fix bug; test=develop

* resolve confilct

* resolve confilct; test=develop

* polish code; test=develop

* polish code; test=develop

* change mutable data to ctx alloc; test=develop

* make format same with ci; test=develop

* fix format error with ci; test=develop

* 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

* move operators/math/math_function_* to pten/kernels/func
* namespace from `paddle::operators::math` to `pten::funcs`

* Merged LoDTensor with Tensor,test=allcases

* Patched python level LoDTensor

* Patched python level LoDTensor

* Merge Tensor into DenseTensor

* Fixed namespace issues,test=allcases

* Fixed merge issues

* Fixed inference issues

* Fixed NPU test issues

* Fixed merge issues

* refine structure for cuda and rocm

* update

* update

* update

* update

* fix bn

* fix

* add unittest

* fix cpu

* add double grad compute for batch norm,test=develop

* fix unittest, test=develop

* remove unuse tensor,test=develop

* add format,test=develop

* update, test=develop

* update err info, test=develop

* update, test=develop

* Add trainable_statistics in attr for batch_norm
* Unifying behavior of dynamic graph and static graph

* add inplace_abn_op. test=develop

* update error information about batch_norm_grad

* update bn,test=develop

* batch_norm momentum support variable. test=develop

* fix format. test=develop

* add batch_norm momentum variable example. test=develop

* move MomentumTensor to training branch. test=develop

* split example. test=develop

* fix doc. test=develop

* fix PADDLE_ENFORCE ci. test=develop

* fix format. test=develop

* fix_bn

* revert unittest,test=develop

* fix bn

* fix spelling errors; test=develop

* Update API.spec

update md5

* Update API.spec

* change the order of api;test=develop

* fix cudnn batch norm accuracy test=develop

* fix cudnn batch norm accuracy test=develop

* disable failed test for later fix test=develop

* Support Sync Batch Norm.
* Note, do not enable it in one device.

Usage:

build_strategy = fluid.BuildStrategy()
build_strategy.sync_batch_norm = True
binary = fluid.compiler.CompiledProgram(tp).with_data_parallel(
        loss_name=loss_mean.name,
        build_strategy=build_strategy)

* Enable BatchNorm to use global mean and variane during training
* Update doc and follow comments.

test=develop

Fix code to support cpplint syntax check

test=develop

* add fp16 backward support
test=develop

* add sum_op fp16 test

* disable test_dist_save_load
test=develop

* add check_grad for sum

* add unit test for softmax_grad fp16
test=develop

* add scale_op unit test

* add mul_grad_op unit test for fp16

* add cross_entropy_grad and eman_grad unit test for fp16
test=develop

* fix cross_entropy unit test

* add pool2d fp16 unit test

* refine conv2d fp16 unit test
test=develop

* refine activation unit test
test=develop

* fix ci
test=develop

* follow zhihong's comment, copy from https://github.com/PaddlePaddle/Paddle/pull/12796
test=develop

* Fix batch norm when only 1 elements in normzalize dimension during training.

* "fix double type error"

* "fix ci"