arXiv:2410.14109cs.LG2024-10ICLR被引 7

通过学习连续边方向,提升GNN的信息传递能力。

Improving Graph Neural Networks by Learning Continuous Edge Directions

  • 为图边赋予可连续变化的方向,实现定向信息流动。
  • 在多个数据集上显著优于传统GNN,尤其在图集成数据上表现突出。
  • 适合基因调控网络等具有多轮节点特征的图数据场景。

图神经网络(GNN)通常采用类似无向图扩散的消息传递机制,常导致节点特征同质化,降低节点分类等任务的区分能力。本文的核心思路是为图边分配模糊的连续方向——方向可在节点i指向j与j指向i之间连续变化——使特征能优先单向流动,支持长程信息传递。我们引入一种新的复数拉普拉斯算子,用于有模糊边的有向图,实部与虚部分别表示相反方向的信息流。基于此,提出通用框架CoED GNN,用于学习模糊边上的连续方向,并通过扩展的有向图韦斯费勒-莱曼(WL)同构测试证明其表达能力。该架构对入边和出边聚合的消息分别处理,结合节点自身特征。由于连续边方向可微,可与GNN权重联合通过梯度优化学习。CoED GNN特别适用于图结构固定但存在多个节点特征实现的图集成数据,如基因调控网络、网页连接图和电力网络。大量实验表明,在合成与真实图集成数据集上,学习连续边方向显著提升性能,优于现有方法。

原文摘要 · Abstract (English)

Graph Neural Networks (GNNs) traditionally employ a message-passing mechanism that resembles diffusion over undirected graphs, which often leads to homogenization of node features and reduced discriminative power in tasks such as node classification. Our key insight for addressing this limitation is to assign fuzzy edge directions -- that can vary continuously from node $i$ pointing to node $j$ to vice versa -- to the edges of a graph so that features can preferentially flow in one direction between nodes to enable long-range information transmission across the graph. We also introduce a novel complex-valued Laplacian for directed graphs with fuzzy edges where the real and imaginary parts represent information flow in opposite directions. Using this Laplacian, we propose a general framework, called Continuous Edge Direction (CoED) GNN, for learning on graphs with fuzzy edges and prove its expressivity limits using a generalization of the Weisfeiler-Leman (WL) graph isomorphism test for directed graphs with fuzzy edges. Our architecture aggregates neighbor features scaled by the learned edge directions and processes the aggregated messages from in-neighbors and out-neighbors separately alongside the self-features of the nodes. Since continuous edge directions are differentiable, they can be learned jointly with the GNN weights via gradient-based optimization. CoED GNN is particularly well-suited for graph ensemble data where the graph structure remains fixed but multiple realizations of node features are available, such as in gene regulatory networks, web connectivity graphs, and power grids. We demonstrate through extensive experiments on both synthetic and real graph ensemble datasets that learning continuous edge directions significantly improves performance both for undirected and directed graphs compared with existing methods.

图神经网络方向学习信息传递图集成

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