* Add softmax_with_cross_entropy and smooth_l1 in Python API.

* Fix doc format.

* dynamic send/recv selected rows

* update by comment

* fix by comment

* dist train support lr decay

* update by comment

* revert elementwise method creator

* delete comment

* Refine target_assign_op to unify the classification and regression targets assignment.

* Fix the unit testing.

* Fix conflicts.

move paddle/pybind/pybind.h to paddle/fluid/pybind/pybind.h, and cancel the test_parallel_op temporary

* Added an elementary test case for CSP

* removed input

* Rename test file to avoid running in CI

* Fix YAPF error

* Remove one line function handler

* Add unit-test and example

* Fix type error

* Fix unit test cases

* Fix init error for cudaplace

* Change unit-test options

* initial commit

* fix bug

* end of file fix

* address comments

* initial commit

* minor fix

* remove redundency

* address comments

* Save the inference model in Python example of recommender_system.

* Add infer() in Python unittest recommender_system.

* Add C++ inference unittest of recommender_system.