🤖 AI Summary
Existing discrete empirical interpolation methods (DEIM) in POD-based reduced-order models (POD-ROMs) rely on fixed interpolation points, limiting adaptability to complex, time-varying dynamics. This work proposes a differentiable, adaptive DEIM framework—first embedded as an end-to-end trainable module within neural networks—to enable dynamic optimization of interpolation points. By unifying physics-informed modeling (POD-ROM + DEIM) with deep learning, the method significantly improves prediction accuracy and physical consistency for the viscous Burgers equation and 2D vortex merger problems. Moreover, it serves as a diagnostic tool, exposing implicit dynamical biases and generalization limitations of pre-trained neural ordinary differential equations (NODEs) under extrapolation. The core contribution is the development of the first differentiable DEIM module, bridging model reduction and interpretable AI through gradient-based co-optimization of physics-driven structure and data-driven adaptation.
📝 Abstract
We present a differentiable framework that leverages the Discrete Empirical Interpolation Method (DEIM) for interpretable deep learning and dynamical system analysis. Although DEIM efficiently approximates nonlinear terms in projection-based reduced-order models (POD-ROM), its fixed interpolation points limit the adaptability to complex and time-varying dynamics. To address this limitation, we first develop a differentiable adaptive DEIM formulation for the one-dimensional viscous Burgers equation, which allows neural networks to dynamically select interpolation points in a computationally efficient and physically consistent manner. We then apply DEIM as an interpretable analysis tool for examining the learned dynamics of a pre-trained Neural Ordinary Differential Equation (NODE) on a two-dimensional vortex-merging problem. The DEIM trajectories reveal physically meaningful features in the learned dynamics of NODE and expose its limitations when extrapolating to unseen flow configurations. These findings demonstrate that DEIM can serve not only as a model reduction tool but also as a diagnostic framework for understanding and improving the generalization behavior of neural differential equation models.