* change fluid.mean to paddle.mean

* reverse some old code examples

* use yapf to format all python file

* yapf exclude two unittests file for they rely on writing and reading file, and format will break them

* disable diff_py_file because too many diff files cause command following failed

* 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

* support cond in clone, test=develop

* refine code, test=develop

* refine code, test=develop

* follow comments, test=develop

* refine code, test=develop

* add prune when test_program.clone is executed after optimizer.minimize

* add unittest, test=develop

* add resnet and transformer test case, test=develop

* add regularization for optimizer & program compare function, test=develop

* add lstm unittest, test=develop

* polish code based on review comment, test=develop

* adapt to interface change in framework._prune, test=develop

* update API.spec, test=develop