Evolving Computation Graphs
Andreea Deac Jian Tang
Graph neural networks (GNNs) have demonstrated success in modeling relational
data, especially for data that exhibits homophily: when a connection between
nodes tends to imply that they belong to the same class. However, while this
assumption is true in many relevant situations, there are important real-world
scenarios that violate this assumption, and this has spurred research into
improving GNNs for these cases. In this work, we propose Evolving Computation
Graphs (ECGs), a novel method for enhancing GNNs on heterophilic datasets. Our
approach builds on prior theoretical insights linking node degree, high
homophily, and inter vs intra-class embedding similarity by rewiring the GNNs'
computation graph towards adding edges that connect nodes that are likely to be
in the same class. We utilise weaker classifiers to identify these edges,
ultimately improving GNN performance on non-homophilic data as a result. We
evaluate ECGs on a diverse set of recently-proposed heterophilous datasets and
demonstrate improvements over the relevant baselines. ECG presents a simple,
intuitive and elegant approach for improving GNN performance on heterophilic
datasets without requiring prior domain knowledge.