How to understand learn automatically “heuristic”

[jiuzhangio]

Hi, Dr. Zhang

It's really a nice work for "Link Prediction Based on Graph Neural Networks". I have a question when learning this papr,

This paper aims to learn automatically a “heuristic” that best explains the link formations. However, you select h only from {1, 2} and manually choose h according to the performance of AA or CN in some cases. So, I want to know how to understand such a automatically heuristic?

Looking forward to your reply, thanks for your time.