三大类方法：
1.Methods Based on Node Neighborhoods
- Common neighbors
- Jaccard’s coefficient and Adamic/Adar
- Preferential attachment
2.Methods Based on the Ensemble of All Paths
- Katz(1953).
- Hitting time, PageRank, and variants
- SimRank (Jeh & Widom, 2002).
3.Higher Level Approaches
- Low-rank approximation
- Unseen bigrams
- Clustering
FIG. 1. Values for score(x, y) under various predictors; each predicts pairs x, y in descending order of score(x, y). The set T(x) consists of the neighbors of the node x in Gcollab.
参考资料：
[1]David Liben-Nowell,Jon Kleinberg.The Link-Prediction Problem for Social Networks[J].JOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, 58(7):1019–1031, 2007.
