* fix:
1. infernce multi card occupy
2. facebox model inference occupy too much
test=develop

* refine python api comments: shuffle, while, scale, sampled_softmax_with_cross_entropy, scatter,
round, sin, sqrt, shape, split, soft_relu, slice, selu, ifelse, switch.
test=develodp

* fix conflict error.
test=develop

fix im2sequence padding bug

* update python APIs

test=document_preview test=develop

* update API.spec

test=document_preview

test=develop

* update merge_selected_rows

* update API.spec

test=document_preview

test=develop

* update API.spec

test=document_preview

test=develop

* fix the comment of less_than

test=develop

test=document_preview

* update API.spec

test=develop

test=document_preview

* update API.spec

test=develop

test=document_preview

* update API.spec

test=develop

test=document_preview

* update API.spec

test=develop

* update API

test=develop

* [DOC] Fix api docs, test=develop, test=document_preview

* [DOC] Fix api annotation: fluid.layers.tensor_array_to_tensor. test=develop, test=document_preview

* test=develop, test=document_preview

update MD5 of tensor_array_to_tensor

* fix the api example for create_global_var, create_parameter, SGDOptimizer, RMSPropOptimizer, MomentumOptimizer, LarsMomentumOptimizer, FtrlOptimizer
test=develop

* add example for adamoptimizer
fix API.spec
test=develop

* test=develop

* test=develop

* fix unique_name growth bug in dygraph mode,test=develop

* change generate_tmp to generate_with_ignorable_key,test=develop

* fix example; test=develop

* fix api spec; test=develop

* fix api spec; test=develop

* add doc check
test=develop
test=document_preview

* test=develop,test=document_preview

add blank line to fix format, add one more "import"

* fix bug; test=develop

* fix bug; test=develop

* Fix the example code in some Python API.
test=develop

* Fix the example code in some Python API by adding import.
test=develop

* This PR adds broadcast for multi-process. And it could be used in dynamic graph to broadcast parameters.

Python examples of fluid.layers.io.double_buffer and some BuildStrategy's methods.

* fix api example. test=develop

* fix API.spec. test=develop

* fix spectral_norm format. test=develpp

* merge develop

* add import. test=develop

* fix indent. test=develop

* fix indent. test=develop

* add import fluid. test=develop

* fix bpr data_norm teacher_student_sigmoid , test=develop test=document_preview

修复了bpr_loss data_norm teacher_student_sigmoid_loss三个api, 同时修复了continuous_value_model文档英文拼写错误

* fix api doc according to the reviewer's comment test=develop

* Fix examples of fluid.layers.sums.
test=document_preview

* Correct the example of DynamicRNN and its functions.
test=develop

* Add 'import paddle.fluid as fluid' to examples.
test=develop

* Update API.spec.
test=develop

* Add space lines.
test=develop

* Update the API.spec.
test=develop

* Add api doc code examples

add or fix topk, squeeze, stack, StaticRNN,
StaticRNN memory in doc

test=develop
Signed-off-by: Nzhaoyuchen <zhaoyuchen01@baidu.com>

* Add squeeze md5.

test=develop
Signed-off-by: Nzhaoyuchen <zhaoyuchen01@baidu.com>

* Add import package

test=develop
Signed-off-by: Nzhaoyuchen <zhaoyuchen01@baidu.com>

* test=develop

* test=develop

* test=develop

* add collect fpn proposals op,test=develop

* test=develop
add sign op

* Update nn.py

test=develop
delete stop_gradient assignment

* Fix the example code in some Python API
* Update paddle/fluid/API.spec
* Fix some examples format

* test=develop
add elementwise_mod and elementwise_floordiv, fix equation problem in elementwise_mod

* modified formula for lrn

test=develop

* modified api.spec

test=develop

* fix API examples, test=develop

* Fix data and reader related api doc

* Fix data and reader related api doc

Review and fix the example code in some reader related API doc.

These APIs are:

Fix existing API example codes:

paddle.fluid.io.PyReader
paddle.fluid.layers.batch
paddle.fluid.layers.data
paddle.fluid.layers.Preprocessor
paddle.fluid.layers.py_reader
paddle.fluid.program_guard

Add new example codes:

paddle.fluid.io.PyReader.decorate_batch_generator
paddle.fluid.io.PyReader.decorate_sample_generator
paddle.fluid.io.PyReader.decorate_sample_list_generator
paddle.fluid.io.PyReader.reset
paddle.fluid.io.PyReader.start

test=develop

* Add changes to API.spec after changing doc.

test=develop

* Add blanks after python example code

test=develop

* Add blank line at py_reader example code

test=develop

* Merge API.spec

test=develop

* Modify reader.py based on reviewer's comment

test=develop

* Modify API.spec after changing doc

test=develop

* Change reader.py based on reviewer's comment

* Modify example code of decorate_sample_generator

test=develop

* Fix example code of PyReader based on reviewer

test=develop

test=develop

* fix api doc of hash, relu, concat, argmin, argmax, argsoft and all activations funcs with no attrs

test=develop

* refine doc example code

test=develop

* remove >>> in doc example

test=develop

* refine python code block

test=develop

* update API spec

test=develop

* add attr axis infershape. test=develop

* add CUDA kernel. test=develop

* fix unittest. test=develop

* fix unittest for soft_label. test=develop

* fix fp16 unittest. test=develop

* remove comment code. test=develop

* refine test for axis. test=develop

* add python api. test=develop

* fix doc. test=develop

* fix fp16 unittest. test=develop

* fix ngraph test. test=develop

* fix ENFORCE for test_imperative_transformer. test=develop

* fit for ngraph test. test=develop

* fix after rebase develop. test=develop

* fix doc. test=develop

* fix API.spec. test=develop

* fix test_layers. test=develop

* fix format. test=develop

test=develop

* refine api comment, test=develop

* fix unexecutable API comments, test=develop

* add API.spec,test=develop

* fix distribute fpn proposals, test=develop

fix python3 run_time_error in layers.ops caused by locals()

fix runtimeerror : dictionary changed size during iteration when calling uniform_random in python3+