improve pow op according to reviews:
1. Delete unnecessary judgement statements in PowGradOpDescMaker;
2. Improve test of test_api;

overload GetKernelTypeForVar

add stop_gradient=True when attr(factor) is tensor Variable, change examples in API pow.
test=develop,test=document_preview

add support parameter inference when argument shape is a list containing integer and tensor variable;
test=develop

fix reshape op according to reviews:
1. improve or message;
2. improve test of test_api.
test=develop,test=document_preview

fix reshape op: Add error message in nn.py, test=develop

add stop_gradient=True when attr(shape) is tensor Variable.
change examples in API reshape.
test=develop,test=document_preview

add support parameter inference when arguments starts or ends is a list containing integer and tensor variable;
test=develop,test=document_preview

improve slice op according to review(from hongyu). test=develop

fix slice op according to review: infer_flags, test=develop

fix slice op: improve overload operator __getitem__ to support attrs(starts and ends) are Variable.
test=develop,test=document_preview

fix test_slice_op: add TestSliceOp_decs_dim_6 to resolve conflict with test_slice_ngraph_op. test=develop

add stop_gradient=True when attr(starts) or attr(ends) is tensor Variable.
test=develop,test=document_preview

1. add tensor support for argument expand_times in expand op;
2. add support parameter inference when argument expand_times is a list containing integer and tensor variable;

improve expand op according to reviews:
1. add doc of ExpandTimes in expand_op.cc;
2. improve the test of test_api.

add stop_gradient=True when attr(expand_times) is tensor Variable, change code examples.
test=develop,test=document_preview

remove unused accuracy-diff warpctc-cudnn implementation

test=develop

* delete args on linear_chain_crf_op doc

* delete args on linear_chain_crf_op doc

* delete args on linear_chain_crf_op doc

* add code example

* fix api doc

* fix doc of crf

* fix doc of crf

* add test=develop

* modify API.spec, test=develop

* delete useless raw variables in Conv2D, test=develop

* adjust the vars number in test_graph_wrapper to pass unittest, test=develop

* add scatter_nd op, test=document_preview test=develop

* fixed the document, test=document_preview test=develop

* modify the notes, test=document_preview test=develop

* remove the ShareDataWith, test=develop

* add padding in linear_chain_crf op

* modify API.spec

* add linear_chain_crf_op.cc and linear_chain_crf_op.h

* remove useless unit test , test=develop

* modify API.spec, test=develop

* remove some blanks in nn.py , test=develop

* fix some bugs on nn.py and API.spec ,test=develop

* fix nn.py, test=develop

* fix API.spec ,test=develop

* fix bug of CI test in test_linear_chain_crf_op.py

* fix bug of CI test in test_linear_chain_crf_op.py, test=develop

* remove paddle_enforce, test=develop

* remove paddle_enforce, test=develop

* remove paddle_enforce, test=develop

* remove paddle_enforce, test=develop

* remove paddle_enforce, test=develop

* remove paddle_enforce, test=develop

* modify nn.py, test=develop

* fix API.spec, test=develop

* fix unittest bug, test=develop

* Support looking up embeddings from BoxPS.
* Add a _pull_box_sparse op, for now this op is not exposed to users.
* Add a BoxHelper class, providing 'BeginPass', 'EndPass', 'FeedPass' functions and so on.
* Add 'BoxPSDataset' in python code.
* Add a compile options WITH_BOX_PS and a MACRO PADDLE_WITH_BOX_PS.
* Add UT.
* More concrete information pls refer to: https://github.com/PaddlePaddle/Paddle/pull/18982

* fixed the code for coverage

* fixed the document,test=document_preview test=develop

* add topk_avg_pooling

* refine api doc and modify api.spec test=develop

Fix mean_iou api misleading example

* improve sequence_conv api doc test=develop

* add warning for padding param test=develop

modify into deprecated

* support tensor input with padding for warpctc op

* merge with develop

* test=develop

* modified python API examples test=develop

* nn.py is modified for code coverage test=develop

* update documents info about warpctc op in API.spec test=develop

* add test_warpctc_with_padding in test_layers test=develop

* add warning log for cuda_version back to warpctc_op.cc

* modify API.spec for warpctc op test=develop

* modify API.spec

* update warpctc test to new CompiledProgram API test=develop

* modify code examples for warpctc op test=develop

* modify API.spec for warpctc op test=develop

* modify API.spec for warpctc op test=develop

* Fix data parallel & sequence mask in dygraph

test=develop

* Revert change in data_parallel

test=develop

* add matrch_matrix_tensor op test=develop

* fix ignore unittest if with_mkl=off test=develop

* clean code and rm is_test param test=develop

* modify API.spec test=develop

* rm useless code in search_compute.h test=develop

* modify api.spec test=develop

* modify default_grad.spec test=develop

* Add API test code test=develop

* clean code in search_computer.h

* modify PADDLE_ENFORCE and clean search_compute.h test=develop

* fix code style test=develop

Remove is_test parameter of FC op. The parameter is_test is not used anywhere.

* instag lod tensor impl

* First PR for instag

* First PR for instag

* Before adding Selection Rows.

* Change name from instag to filter_instag, add upgrade the impl of filter_instag

* Change name from instag to filter_instag, add upgrade the impl of filter_instag

* Fix yapf error in gradient_checker.py to pass Travis-CI

* Fix Filter Instag Grad test=develop

* Fix Filter Instag Grad test=develop

* 1) Fix API.spec, add filter_instag Op. 2) Add Vector Support for CUDA. test=develop

* Impl Loss_weight and empty output handler

* change Loss Weight datatype to Float32, and add Loss Weight as 2nd output

* 1) Support Tensor Input(without LOD) 2) Add Unit test

* Filter By Instag Final test=develop

* Update API.spec for filter_by_instag test=develop

* Update API.spec for filter_by_instag 2 test=develop

* Add Filter By Instag Coverage

* code format of test_layers.py

* code format test_layers.py test=develop

* Make API args more readable test=develop

* Make API args more readable and pass code format test=develop

* Filter By Instag Op, Rename Map to Index Map test=develop

* Filter By Instag Op, code format err in filter_by_instag_op.cc  test=develop

* Filter by instag op: code format of cpp files test=develop

* Filter by instag Op: Api spec modification test=develop

* Filter by instag Op: Api spec doc id modification test=develop

* Filter by instag Op: Api spec and doc preview  test=develop test=document_preview

* Filter By Instag Op, fix doc erro test=document_preview test=develop

* Filter By Instag Op, fix doc err and Api spec test=document_preview test=develop

* Filter By Instag Op, fix Api spec test=document_preview test=develop

* Filter By Instag Op, fix Paddle Encoforce deprecated warning test=document_preview test=develop

* Filter By Instag Op, fix Paddle Encoforce deprecated and code format warning test=document_preview test=develop

* 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

* 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 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

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

* 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 dropout in nn.py

* fix g_param shape mismatch in WeightNormParamAttr

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

* test=develop test=document_preview

* Update API.spec

* 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

* support center loss
* change tensor copy  api to high level api tensorcopy

* test=develop rewrite the center_loss cuda_kernel to make it faster
and add document of the center loss api,also update test function

* test=document_preview test=develop
update document of center loss

* test=document_preview test=develop
modify API.spec modify test code remove nouse const_cast

Update conv2d transpose link

test=develop

* replace link

* update api.spec

* fix mistake

* fix logical APIs

test=develop

test=document_preview

* fix isfinite

* update matmul comments

* update API.spec

test=document_preview

test=develop

* update API.spec

test=document_preview

test=develop

* update API.spec

test=document_preview

test=develop

* Make lod reset op support for append lod level.

* Fix API.spec
test=develop

* Fix unitest.
test=develop

* Add python api for lod append.
test=develop

* Fix API.spec
test=develop

* Fix format of doc.
test=develop

* Fix unitest.
test=develop

* Fix doc.
test=develop

* supports distributed classification training
* update API.spec
* fix evenly division in python3
* change "index_range" to "index_num" in shard_index operator
test=document_preview
test=develop