* add unit test for square error cost op

* 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

fix wrong place with distributed_lookup_table

* change approve site ;test=develop

* test=develop

test=develop

test=develop

* Open fuse all reduce op
test=develop

* Add Fuse optimization op log

* Add log in fuse_optimizer op pass and fuse all_reduce op pass

* replace with boost::optional<bool>
test=develop

* Polish code
test=develop

* fix code coverage
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

Fix test_parallel_executor_test_while_train 

* fix vlog level and fuse option type
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

* Enable fused_all_reduce_op_handle support GPU and CPU Gradients

* update dygraph api-doc and backward api-doc, test=develop

* update dygraph api-doc and backward api-doc, update api.spec, test=develop

* update dygraph api-doc and backward api-doc, update api.spec, test=develop

* update API.spec, test=develop

* fix dygraph partitial backward problem, test=develop

* add unittest, fix ClearGradient. test=develop

* add filter and error in python side, test=develop

* rebase develop, test=develop

* bug fix for list equals in py3.5, test=develop

* bug fix for list equals, test=develop

remove unused accuracy-diff warpctc-cudnn implementation

test=develop

* split teacher checkpoints with student checkpoints, test=develop

* add unittest for graph.merge(), test=develop

* MKLDNN handler cleanup

* MKLDNN handler cleanup
test=develop

test=develop

Add document annotations for FLAGS that need to be open to external developers test=develop (#19692)

Add document annotations for FLAGS that need to be open to external developers

* 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

Fix float16 optimizer