Link prediction is the task of forecasting missing or future connections between nodes in a graph.
Local heuristics like Common Neighbors, Jaccard Coefficient, and Adamic-Adar Index are based on the immediate neighborhood of nodes.
Preferential Attachment is a different approach where nodes with higher degrees are more likely to form links.
Global heuristics like Katz Index and Rooted PageRank consider paths or the entire graph structure for link prediction.
Machine learning approaches for link prediction treat it as a binary classification task and can outperform heuristics.
VGAE combines Graph Auto-Encoder (GAE) and Variational Auto-Encoder (VAE) to predict missing links based on learned hidden structure.
VGAE's encoding step maps nodes to latent variables in a hidden space, while the decoding step predicts edges between nodes.
SEAL (Subgraph Embedding-based Link Prediction) looks at local subgraphs instead of global node embeddings for predicting links.
SEAL learns structural patterns directly from examples, providing better performance for some problems.
VGAE and SEAL are powerful GNN-based methods that offer improved link prediction results compared to traditional heuristics and basic machine learning models.
Understanding link prediction methodologies, from simple heuristics to advanced GNN-based models like VGAE and SEAL, can enhance predictions in a variety of applications.