Graph neural networks (GNNs) have become compelling models designed to perform learning and inference on graph-structured data, but little work has been done on understanding the fundamental limitations of GNNs to be scalable to larger graphs and generalized to out-of-distribution inputs. In this paper, we use a random graph generator that allows us to systematically investigate how the graph size and structural properties affect the predictive performance of GNNs. We present specific evidence that, among the many graph properties, the mean and modality of the node degree distribution are the key features that determine whether GNNs can generalize to unseen graphs. Accordingly, we propose flexible GNNs (Flex-GNNs), using multiple node update functions and the inner loop optimization as a generalization to the single type of canonical nonlinear transformation over aggregated inputs, allowing the network to adapt flexibly to new graphs. The Flex-GNN framework improves the generalization out of the training set on several inference tasks.

本文研究了图神经网络的可扩展性和推广性，并提出了灵活的 GNNs 框架，通过多种节点更新函数和内部循环优化，使网络能够灵活适应新图并在多项推理任务中提高泛化能力。

灵活表示多模块图神经网络以实现更好的泛化