* rpc retry for asycsend/get/prefetch

* test=develop, change retry vlog level to 3

* test=develop, set default grpc_retry_times is 3

* update elementwise double grad to save gpu memory, test=develop

* update elementwise_mul/div_grad_grad to save memory, test=develop

* remove eval function in eigen statement to save memory, test=develop

* add unittest for elementwise_div_grad_grad without dout, test=develop

* add unittest for elementwise_add_grad_grad without ddx, test=develop

* add float16 cuda kernel for elementwise double grad op, test=develop

test=develop

* add deformable conv v1 op, test=develop

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

* cpu conv_grad_grad

* Implement the operator with sprase matrix multiply

* Update the URL of mklml library.

test=develop

* Disable MKLML implematation when using no-linux.

test=develop

* optimize bp with mkl sparse matrix
test=develop

* tmp add fused_emb_seq layer

* Add the support of padding_idx attribute.

test=develop

* add padding_idx support
test=develop

* implement grad refer lego
test=develop

* Refine the codes related to fc op.

* Add GPU implementation for fc functor.

* Apply fc_fuse_pass in GPU inference.
test=develop

* Change the cmake for fc op.

* Change PADDLE_ENFORCE to PADDLE_ENFORCE_EQ.

* Add an attribute to set the activation type in fc_op.

* Enhance the unittest of fc_op.
test=develop

* Remove the declaration of FCOpGrad back to the header file.
test=develop

* Set default value for newly added arguments in test_fc_op.
test=develop

* Enhance fc_fuse_pass to enable fusing relu.

* Allow print the shapes of var_desc in graph.
test=develop

* Enhance fc_fuse_pass_tester.

* Remove the use of PADDLE_ENFORCE.
test=develop

* Correct the number of ops after fusing.
test=develop

* Fix a typo.
test=develop

* Set activation_type to null when there is no relu in fc.
test=develop

* Refine fc_fuse_pass's codes.

* Enable the set of shape for tensor.

* Refine repeated_fc_relu_pass and add unittest.
test=develop

* add kernel for squeeze_op, test=develop

* delete comment, test=develop

* add kernel for unstack_op, test=develop

* add kernel for unstack_op, test=develop

* add kernel for unstack_op, test=develop

* adjust the code format, test=develop

* modify some comment, test=develop

test=develop

* add one_hot_v2_op to remove last_dims==1 test=develop

* add api unittest code for CI_Coverage test=develop

* improve CI_Coverage rate by adding test_with_depth test=develop

test=develop

- fix to BWD

test=develop

TemporaryAllocator is a singleton used for allocating memory for Cudnn. Since it is a singleton, we can delete it for better performance in memory.

We replace TemporaryAllocator by CUDADeviceContextAllocator and CUDADeviceContextAllocation, which uses stream callback to delete the memory allocated for the stream to avoid singleton.

Also added data_feed_proto to operator to fix CI in CPU compilation

* make leaky relu inplacable, test=develop

* force add unittests to pass coverage, test=develop

test=develop

- Cosmetic fixes

test=develop

* Refine the codes related to fc op.

* Add GPU implementation for fc functor.

* Apply fc_fuse_pass in GPU inference.
test=develop

* Change the cmake for fc op.

* Change PADDLE_ENFORCE to PADDLE_ENFORCE_EQ.

* Add an attribute to set the activation type in fc_op.

* Enhance the unittest of fc_op.
test=develop

* Remove the declaration of FCOpGrad back to the header file.
test=develop

* Set default value for newly added arguments in test_fc_op.
test=develop

* Remove constraint that last dimension is forced to be 1 in huber_loss
test=develop

* add y[rank-1] == 1 when x_rank=y_rank test=develop

* modify into contain_unknown_dim test=develop

remove unused accuracy-diff warpctc-cudnn implementation

test=develop

* MKLDNN handler cleanup

* MKLDNN handler cleanup
test=develop

* merge_empty_lod_tensor, test=develop

* fix multiclass_nms, test=develop

* refine API.spec, test=develop

* add unittest case for fetch, test=develop

* add lod tensor test, test=develop

* return index for multiclass_nms, test=develop

* add api for multiclass_nms2

* update API.spc, test=develop

* refine api doc, test=develop

* fix test_detection.py, test=develop

* polish code, test=develop

* add more unittest case, test=develop

* fix instag op

* fix instag bug: Some tiny logical error, occurring when ins_tag (2nd input) is multiple. test=develop

* add kernel for unsqueeze_op, test=develop

* add kernel for unsqueeze_op, test=develop

* add kernel for unsqueeze_op, test=develop

* paddle::framework::vectorize() templatization

test=develop

* update pybind/imperative.cc

test=develop

* revert update on unsqueeze_op.cc and warpctc_cudnn_op.cu.cc

test=develop

fix cmakelist deps: remove unnecessary deps and add proper op deps

* remove -Wmaybe-uninitialized warning

test=develop

* remove uninitialized op_handle_ in scale_loss_grad_op_handle.cc

test=develop

test=develop

* test=develop codegen for fused elementwise operation

* fix test=develop

* delete useless raw variables in Conv2D, test=develop

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

* test=develop,  communicator merge add => merge average