* mem opt

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* refine code  test=develop

* refine code  test=develop

* refine code  test=develop

* refine code  test=develop

* refine with cub test=develop

* fix mkldnn test && remove comments && test=develop

* polish code && test=develop

* add only_forward test && test=develop

* add multi process start script test=develop

* refine tool test=develop

test=develop

add a GAN model in imperative mode

remove file cnt assignment in async_executor

test=develop

test=develop

* fix mac cmake version 3.13 test=develop

* fix again test=develop

test=develop

test=develop

* refactor tree2col operator with new memory mechanism test=develop

* test=develop

* test=develop

* Modified API according to panyx0718 test=develop

* fix API change according to heavengate test=develop

* Modify API comment test=develop

test_analyzer_mm_dnn runs in serial

test=develop

test=develop

add pyramid_dnn c++ inference test

* Revert the modification of while_op in #14764.
test=develop

* Remove the dependency of GRPC_DEPS.
test=develop

gru add origin mode

test=develop

fix analysis config bug

fix unit test cases

test=develop

Fix the exception when tensor format is x

test=develop

test=develop

disable the parallel mode for adam op on windows test=develop

remove unused doc folder

* Simplify the compare op for CPU.

* Use asynchronous tensor copy in reshape_op's kernel.

* Optimize while_op for test, avoiding creating variables every time.
test=develop

* Enable the cache of kernel type and kernel function.
test=develop

* Enable profiling with gperftools.

* Remove flags for testing, and fix the linking error.
test=develop

* Delete the codes of ChooseKernel.
test=develop

* Fix bug when preparing ExecutorPrepareContext for while_op.

* Fix missing depending on grpc libraries.

* Remove the redundant print.
test=develop

* Follow comments.

* Remove the codes related to prepare the ExecutorPrepareContext for while_op.
test=develop

Enable element_wise_add operator for a ngraph engine

Enable softmax operator for a ngraph engine

test=develop