* add hard_swish activation op (new op)
test=develop

* remove redundancy files

* modify document content of HardSwish OP

* add API test in test_layers.py

* add dynamic_graph for test_hard_swish

Polish fleet API to support cuda collective mode and nccl2 mode

* add tensorrt support for windows

* fix overflow by int32 mul test=develop

* fix reference nullptr

* fix codestyle test=develop

* modify to point in ContextProjectFunctor test=develop

* modify to point in ContextProjectFunctor test=develop

* modify . to -> test=develop

* refine embedding padding_idx doc test=develop

* fix math:padding_idx preview bug test=develop

* modify API.spec test=develop

* fix spell error test=develop

* refine dtype parm desc test=develop

add save cache model api in fleet& add slots shuffle in dataset module & add metric op to calculate ctr related metrics (#18871)

* add ctr related metric layer test=develop

* add save cache and slots shuffle test=develop

* add save cache and slots shuffle test=develop

* fix error

* fix error

* fix style for ci

* fix for comments

* change SlotsShuffle input to std::strinf for generality

* fix style

* fix style

* fix style

* fix style

* fix style

* fix style

* fix stylr

* fix style

* fix style

* fix style

* fix style

* fix style

* fix style

* fix style

* fix style

* fix style

* fix style

* fix style

* fix style

* fix style

* change non-const reference to pointer

* fix style

* fix style

* fix style test=develop

* fix style  test=develop

* add return ins num in ctr metric op

* change dtype to float in metric_op.py

* fix error test=develop

* fix style test=develop

* fix API spec

* fix API spec

* fix API spec test=develop

* add UT test=develop

* deprecate python memory optimize, test=develop

* remove memory_optimize in unittests, test=develop

* add unittests to deprecated interfaces, test=develop

* add a place field in DataFeed to denote which place it will feed data to.
* abstract the copy process in CopyToFeedTensor function
* add UT for float32 type and for CUDAPlace

test=develop

* remove compile from PE
test=develop

* add eye op,test=document_preview test=develop

* fix the API.spec, test=develop

* fix the document, test=document_preview test=develop

* add unitest for CI coverage, test=develop

* add trilinear interp. test=develop

* fix unittest. test=develop

* add python api and test_layers. test=develop

* refine API.spec. test=develop

* fix format. test=develop

* add python API test. test=develop

* format code. test=develop

* refine code strcuture. test=develop

* fix format

* fix doc. test=develop

* fix converage. test=develop

* fix format. test=develop

* Enhance fuse optimization op pass
test=develop

* Add call stack info during runtime and compile time
test=develop

* Rename operator_call_stack
test=develop

* Add unit test
test=develop

* follow comment
test=develop

* add fleet util (fleet/utils/fleet_util.py): functions for users' convenience
* add some interface in hdfs util : hdfs is_file、hdfs cat

* add train demo for imdb text classification task

* make inference library release data_feed dataset dataset_factory data_feed_factory

* add String Data Generator

* new feature of train demo: save model params

* New feature of train demo: set training config using gflags

* change code style for CI

* add readme and dataset for imdb demo trainer

* update roi doc in roi_pool and roi_align, test=develop

* fix memory overlapping of fetch var (return of executor.run), test=develop

* fix wrong usage of ParallelExecutor in op_test, test=develop

* remove useless parameter and simplify code

* avoid tensor destruct untimely, test=develop

* add testcase independent of OpTest, test=develop

As mentioned in this link, the last version of NumPy to support Python 2.7 is numpy 1.16.4.

* fix overflow by int32 mul test=develop

* fix reference nullptr

* fix codestyle test=develop

* modify to point in ContextProjectFunctor test=develop

* modify to point in ContextProjectFunctor test=develop

* modify . to -> test=develop

* add var_conv_2d op test=develop

* edit api.spec test=develop

* ignore unittest if with_mkl=off test=develop

* fix python3 division test=develop

* fix ignore unittest bug test=develop

* remove useless code test=develop

* modify api.spec test=develop

* modify default_grad.spec test=develop

* fix profiler doc error, test=develop

* update API.spec, test=develop

Fix dropout in nn.py

* fix g_param shape mismatch in WeightNormParamAttr

* add comment to show why insert reshape in startup_program
test=develop

* fix warpctc.dll not found issue, test=develop

* revert the linux platform change, test=develop

* delete warpctc_lib_path.h.in, test=develop

* add SetPySitePackagePath function

* fix warpctc.dylib not found issue on Mac, test=develop

* improve the paddle lib path setting logic, test=develop

* fix mac ci issue caused by test_warpctc_op unittest, test=develop

* tweak code, test=develop

* update exe.run

* test=develop support Tensor input for ctc_align_op

* test=develop add some comment

make listen and server as exclusive run 

* test=develop test=document_preview

* Update API.spec

* open gc by default, test=develop

* fix test_train_recognize_digits and disable gc when ngraph is enabled, test=develop

* fix conditional_block op eager deletion bug, test=develop

* add some comments to reviewers, test=develop

* support filelist size < trainer num
* pull dense when stop, to make sure local dense params are same as pserver, so save paddle model will save dense model same as pserver
*  enable QueueDataset train same filelist for serveral times

* add fusion_seqpool_cvm_concat test=develop

* simplify pass, test=develop

* fix code style, test=develop

adjust ins weight according to nid slot , user can specify adjust_ins_weight in strategy

* test=develop
Add the op of unique_with_counts, the op is calc the unqiue input of data, and output the corresponding indices and count of data.

* test=develop
Check the input and dtype in the op of unique_with_counts

* test=develop
test=document_preview
update the API.spec for `unique_with_counts`, at the same time, optimize the python api in the op of `unique_with_count`

* test=develop
test=document_preview
Fix some python api problem in the op of `unique_with_counts`, and change the error messsage in this op.

* Fix some API problem in the op of `unique_with_counts`
test=develop
test=document_preview

* test=develop
test=document_preview
Fix the api sample of op `unique_with_counts`, and update api.spec

* fix depthwise conv gpu kernel bug, test=develop
* add more depthwise conv test, test=develop

test=develop