StructComp: Substituting Propagation with Structural Compression in Training Graph Contrastive Learning
Shengzhong Zhang, Wenjie Yang, Xinyuan Cao, Hongwei Zhang, Zengfeng Huang
TL;DR
StructComp introduces a scalable training framework for graph contrastive learning by substituting costly message passing with node compression based on a sparse low-rank diffusion approximation. It uses a graph partition to form compressed features $X_c = P^T X$ and a compressed graph $A_c = P^T A P$, enabling training with an MLP encoder on $X_c$ while retaining full graph structure for inference. Theoretical results establish that the compressed loss closely approximates the original GCL loss with a bound depending on the partition remainder, and multi-view StructComp adds a regularization effect that improves robustness. Empirically, StructComp significantly reduces memory and time requirements while achieving competitive or improved accuracy across small and large graphs, demonstrating strong scalability for diverse GCL models.
Abstract
Graph contrastive learning (GCL) has become a powerful tool for learning graph data, but its scalability remains a significant challenge. In this work, we propose a simple yet effective training framework called Structural Compression (StructComp) to address this issue. Inspired by a sparse low-rank approximation on the diffusion matrix, StructComp trains the encoder with the compressed nodes. This allows the encoder not to perform any message passing during the training stage, and significantly reduces the number of sample pairs in the contrastive loss. We theoretically prove that the original GCL loss can be approximated with the contrastive loss computed by StructComp. Moreover, StructComp can be regarded as an additional regularization term for GCL models, resulting in a more robust encoder. Empirical studies on various datasets show that StructComp greatly reduces the time and memory consumption while improving model performance compared to the vanilla GCL models and scalable training methods.
