Created by: lcy-seso

In our merged codes, there are still lots of comments like this: "The first input of xx", "The second input of xx", https://github.com/PaddlePaddle/Paddle/blob/develop/paddle/operators/cross_entropy_op.cc#L101

Personally, I think this kind of comments is lack of useful information, of course, I know it is the first or the second input of this operator. At least we can try to explain the type, default type/value, or what is the meaning or the usage.

We have this doc https://github.com/PaddlePaddle/Paddle/blob/develop/paddle/operators/name_convention.md and we should follow it and keep on refining the merged comments.