🤖 AI Summary
This study investigates the limited generalization capability of neural ordinary differential equations (nODEs) across graph structures and scales in complex networks. Building upon the Barabási–Barzel vector field, the authors construct an nODE model trained on five canonical classes of graph dynamical systems and systematically evaluate its performance using realistic networks generated via S¹ random geometric graphs with tunable structural properties. The work reveals, for the first time, that degree heterogeneity and the type of dynamical system are the primary factors governing nODE generalization across graphs, while the average clustering coefficient plays a secondary role. The model also demonstrates robustness to missing data and in capturing fixed points. These findings highlight the strong modeling capacity of nODEs on real-world graph structures, yet underscore significant generalization challenges posed by high degree heterogeneity and elevated clustering.
📝 Abstract
Neural ordinary differential equations (neural ODEs) can effectively learn dynamical systems from time series data, but their behavior on graph-structured data remains poorly understood, especially when applied to graphs with different size or structure than encountered during training. We study neural ODEs ($\mathtt{nODE}$s) with vector fields following the Barab\'asi-Barzel form, trained on synthetic data from five common dynamical systems on graphs. Using the $\mathbb{S}^1$-model to generate graphs with realistic and tunable structure, we find that degree heterogeneity and the type of dynamical system are the primary factors in determining $\mathtt{nODE}$s'ability to generalize across graph sizes and properties. This extends to $\mathtt{nODE}$s'ability to capture fixed points and maintain performance amid missing data. Average clustering plays a secondary role in determining $\mathtt{nODE}$ performance. Our findings highlight $\mathtt{nODE}$s as a powerful approach to understanding complex systems but underscore challenges emerging from degree heterogeneity and clustering in realistic graphs.