Predicting links with SEAL
The previous section introduced node-based methods, which learn relevant node embeddings to compute link likelihoods. Another approach consists of looking at the local neighborhood around the target nodes. These techniques are called subgraph-based algorithms and were popularized by SEAL (which could be said to stand for Subgraphs, Embeddings, and Attributes for Link prediction – though not always!). In this section, we will describe the SEAL framework and implement it using PyTorch Geometric.
Introducing the SEAL framework
Introduced in 2018 by Zhang and Chen [6], SEAL is a framework that learns graph structure features for link prediction. It defines the subgraph formed by the target nodes and their -hop neighbors as the enclosing subgraph. Each enclosing subgraph is used as input (instead of the entire graph) to predict a link likelihood. Another way to look at it is that SEAL automatically learns a local heuristic for link prediction.
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