* fix the order of sum

* add doc

* check whether need to copy

* follow comments

Do not set loss@Grad as persistable

avoid duplicated init op for one parameter

* fix the result of unit test

* fix resnext

* compare the result of PE and Exe

* compare the result of reduce and allreduce

* Simplify the travis script.
Now use docker to deploy documentations

* Check for the pull request

* Update paddle_build.sh

* Update paddle_build.sh

optimize profiler

Bugfix/disable anakin test

Revert part of a3ca4c99

Make lookup_table_op and softmax_op supporting high rank tensor

enforce test_parallel_executor_transformer and test_image_classification_resnet to run in serial (#12545)

Improve profiler

Fix pserver can NOT start with DebugString problem

fix: add batch size check in loading data process