* use prefetch to load next mem into cache

test=develop

* remove hard code memcpy om pyramid_hash_ff

test=develop

* fix fetch handler problem and refactor
when a user define FetchHandler class, he or she should initialize a handler
with variable dict. the key of a variable dict is a user defined name,
the value of a variable dict is a Varaible generated from python API.

For each fetching, a user should implement handler function in which
fetched_result_dict will be available and the user can access the fetched value
with user defined keys.

* adapt test_collective_base.py for only two GPU cards available.
test=develop

* fix bug of issue #21259
test=develop

* Disable fusion_group pass for windows and mac. We will do some experiments on Linux first.
test=develop

* Print the subgraph when check failed.
test=develop

* Fix the crash issue when scale or bias was null-pointer.

test=develop

* Add the error message for passing CI.

test=develop

* add int8 kernel to lookup_table op and add dequantize op test=develop

* change paddle_enforce to paddle_enforce_eq test=develop

* change copyright and change some not suitable code test=develop

* remove debug log test=develop

* replace GetInputType with IndicateVarDataType test=develop

* fix EmptyGradMaker test=develop

* fix diff between cpu and gpu test=develop

* use memcopy when int8_t test=develop

Previously, CVM OP was only able to run in CPU. This PR implements its GPU kernel.
What's more, we improve the UTs about CVM OP.

* Avoid the string as the key of map to improve the jit performance.

test=develop

* Use map to replace unordered_map.

test=develop

* polish code details, test=develop

* futher polish hint msg, test=develop

pass the argument `allow_out_of_range` of one_hot op to c++ back end.

* fix fs_client_param bug， user can set this config through fleet_desc_file or fleet config
* test=develop

* general table

* add sparse table
test=develop

* no cvm
test=develop

* add no_cvm
test=develop

* add note
test=develop

* code style
test=develop

* code style
test=develop

* code style
test=develop

* code style
test=develop

* code style
test=develop

* add key of optimizer
test=develop

* solve pslib stop core
test=develop

* barrier
test=develop

* add notes
test=develop

* open dygraph op test, test=develop

* modify to_variable, test=develop

* modify input and output for dygraph, test=develop

* modify input and output for dygraph(fix bug), test=develop

* fix input processing of dygraph op test, test=develop

* fix bug, test=develop

* fix op test, test=develop

* fix forward bug for dygraph, test=develop

* fix mkldnn op test for forward, test=develop

* update nn.py for dygraph, test=develop

* fix crop_tensor_op, test=develop

* fix elementwise_mul_op, test=develop

* fix fill_op, test=develop

* fix some mkldnn op, test=develop

* open backward op test for dygraph, test=develop

* delete log, test=develop

* close backward op test for dygraph, test=develop

* fix bug for edit_distance_op and test_lstm_cudnn_op, test=develop

* fix optest backward bug for dygraph, test=develop

* fix optest backward bug for dygraph, test=develop

* close backward op test for dygraph, test=develop

* close backward op test for dygraph, test=develop

* open dygraph op test, test=develop

* fix op test for dygraph, fix GradOpDescMaker, test=develop

* fix bug for linear_chain_crf_op.h, test=develop

* remove log, test=develop

* remove log, test=develop

* remove log for op_test.py, test=develop

* remove log for op_test.py, test=develop

* fix bug for var_conv_2d_op, change PADDLE_ENFORCE, test=develop

* fix PADDLE_ENFORCE_EQ for hierarchical_sigmoid_op.cc, test=develop

* fix bug for test_increment_ngraph_op.py, test=develop

* fix lod for op test in dygraph, test=develop

* refactor op_test.py to reduce redundant code, test=develop

* fix lod optest, modify InputVar/OutputVar to HasInput/HasOutput, test=develop

* remove debug log, test=develop

* remove redundant code in base.py, test=develop

* fix some error in optest, test=develop

* fix ClearNoNeedBufferInputs function's bug for LoDTensor, test=develop

* refactor op_test.py, test=develop

* remove redundant writing, test=develop

* fix error(get tensor of the grad variable), test=develop

* fix test_concat_mkldnn test_conv2d_mkldnn, test=develop

* fix optest.py for get tensor of LoDTensor, test=develop

* fix optest.py for get tensor of LoDTensor, test=develop

* fix optest.py for get tensor of LoDTensor, test=develop

* fix some redundant code, test=develop

* reslove conflict and rewrite paddle error message, test=develop

* fix mkldnn include. test=develop

* fix mkldnn inlcude. test=develop

* fix fleet util bug in save paddle inference model
* test=develop

* add input type and input data type check for Print_op test=develop

* change api document review;test=develop;test=document_fix

* test=develop;test=document_fix

* general table

* add sparse table
test=develop

* no cvm
test=develop

* add no_cvm
test=develop

* add note
test=develop

* code style
test=develop

* code style
test=develop

* code style
test=develop

* code style
test=develop

* code style
test=develop

* add key of optimizer
test=develop

* fix the CAPI ZeroCopy shape error and reconstruct the output obtain

* use an anonymous namespace to cover the functor

* fix unit tests because of the output of typeid(T).name() is different from linux and windows, test=develop

* add control flow API: case. test=develop

* delete 'raise TypeError' in _error_message() and return a string. test=develop

* polish API document. test=develop

* Enable generating code for a given subgraph.

* Support sorting the subgraph.

* Remove the rearange of expressions because we use the sorted subgraph directly.

* Enable generating code for a subgraph which is composed of grad ops.

* Use expression information to check the accuracy in unittest.

* Separate load and store from computation expressions.
test=develop

* Improve the loading statements in generated codes.
test=develop

* Remove unused arguments from formal list.
test=develop

* Fix topk compile failed on windows
* Use explicit cast for assign data

added splitter "__" between weight name and suffix number to avoid conflicts.

* support set model_filename and params_filename in post_training_quantization, test=develop

test=develop

* optimize assign op to avoid copy data from GPU to GPU, test=develop

* modified GetkernelTypeForVar and just avoid device transform, test=develop

* make Docker to gcc 8.2, test=develop

* add -std=c11 to grpc.cmake, test=develop

* fix PADDLE_ENFORCE ci check bug, test=develop, test=document_fix

* fix PADDLE_ENFORCE match error, test=develop, test=document_fix

test=develop

* fix auc drop first commit test=develop

* update datanorm op

* update datanorm with enforce test=develop

* update test=develop

* update format test=develop

* update format

* update format test=develop

* add unit test test=develop

* update unit test test=develop

* update format test=develop

* update format test=develop

* update API description test=develop

* update API description test=develop

* update format test=develop

* fix codes as comments test=develop

* fix description as comments test=develop

* fix description as comments test=develop

* update codes.. test=develop