🤖 AI Summary
Traditional mesh-based methods struggle with complex geometries when solving high-order PDEs—particularly fourth-order biharmonic equations—while existing Physics-Informed Neural Networks (PINNs) suffer from high computational cost and limited accuracy. To address these challenges, this work proposes RBF-PIELM: a Radial Basis Function-activated Physics-Informed Extreme Learning Machine. It intrinsically embeds physical constraints into the network architecture and replaces iterative gradient descent with a single-step least-squares solution, enabling backpropagation-free training. Experiments on cavity flow and oscillatory stream-function problems demonstrate that RBF-PIELM achieves accuracy comparable to state-of-the-art PINNs, while accelerating training by up to 350× and reducing trainable parameters by over one order of magnitude. Although slightly less accurate than mature mesh-based solvers for highly oscillatory solutions, RBF-PIELM significantly extends the applicability boundary of efficient, lightweight PINN variants for high-order PDE numerical simulation.
📝 Abstract
Partial differential equation (PDE) solvers are fundamental to engineering simulation. Classical mesh-based approaches (finite difference/volume/element) are fast and accurate on high-quality meshes but struggle with higher-order operators and complex, hard-to-mesh geometries. Recently developed physics-informed neural networks (PINNs) and their variants are mesh-free and flexible, yet compute-intensive and often less accurate. This paper systematically benchmarks RBF-PIELM, a rapid PINN variant-an extreme learning machine with radial-basis activations-for higher-order PDEs. RBF-PIELM replaces PINNs' time-consuming gradient descent with a single-shot least-squares solve. We test RBF-PIELM on the fourth-order biharmonic equation using two benchmarks: lid-driven cavity flow (streamfunction formulation) and a manufactured oscillatory solution. Our results show up to $(350 imes)$ faster training than PINNs and over $(10 imes)$ fewer parameters for comparable solution accuracy. Despite surpassing PINNs, RBF-PIELM still lags mature mesh-based solvers and its accuracy degrades on highly oscillatory solutions, highlighting remaining challenges for practical deployment.