* "add metrics"

* "add fluid metrics"

* "add import guards"

* "show warnings"

* "add demo"

* "fix ci"

* "add some details"

* "fix cci"

* "add demo Python"

* "add metrics"

Modify readers to fit the parallel executor

Make cuda_helper.h Pass cpplint

k8s dist train for en

add remove_op, remove_var in Python end

* fix gemm error for cuda 7.5

* fix version number

Fix lost of LoD while splitting tensor in parallel executor.

* Update compile_paddle_lib_en.md

Fix https://github.com/PaddlePaddle/Paddle/issues/8916

* Update compile_paddle_lib_en.md

Crash training, if the number of samples is less than the count of devices.

* add cuda_device_functions.h

* move reduceSum to elementwise_op_function.h

Fix dist transpiler bug

fix python package have no version.py

Simplify DataStructure in SSAGraph

Add title for kernel_hint_design.md & kernel_selection.md

Update build and install/index_en.md