Organizations: National Center for Applied Mathematics Beijing, Capital Normal University, No. 105 West Third Ring Road North, Beijing, 100048, China · The Academy for Multidisciplinary Studies, Capital Normal University, No. 105 West Third Ring Road North, Beijing, 100048, China · Academy of Information Network Security, People’s Public Security University of China, No.1 Muxidi Nanli, Beijing, 100038, China · Institute of Nuclear and New Energy Technology, Tsinghua University, Haidian District, Beijing, 100084, China · School of Mathematical Sciences, Capital Normal University, No. 105 West Third Ring Road North, Beijing, 100048, China
Machine learning, especially physics-informed neural networks (PINNs) and their neural network variants, has been widely used to solve problems involving partial differential equations (PDEs). The successful deployment of such methods beyond academic research remains limited. For example, PINN methods primarily consider discrete point-to-point fitting and fail to account for the potential properties of real solutions. The adoption of continuous activation functions in these approaches leads to local characteristics that align with the equation solutions while resulting in poor extensibility and robustness. A general explicit network (GEN) that implements point-to-function PDE solving is proposed in this paper. The "function" component can be constructed based on our prior knowledge of the original PDEs through corresponding basis functions for fitting. The experimental results demonstrate that this approach enables solutions with high robustness and strong extensibility to be obtained.
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Figure 1: This comparative study demonstrates two approaches for approximating y=sin(x) . (a): Explicit polynomial fitting reveals a critical trade-off: low-degree polynomials (e.g., 3rd-degree, red) fail to capture the curvature of the function within the sampled region (x∈[−1,1]) , whereas higher-degree fitting (5th-7th degrees, orange/green) provides improved in-sample accuracy at the cost of severe overfitting and unstable extrapolation (wild oscillations beyond ∣x∣>1 ). (b): Taylor series expansion exhibits progressive refinement: lower-order approximations (1-2 terms, red/brown) approximate the core trend, whereas higher-order expansions (3-4 terms, green/blue) systematically enhance both the local accuracy and global extrapolation stability of the system by aligning derivative constraints with the intrinsic physics of sin(x) . These divergent extrapolation behaviours underscore the superiority of series expansions over purely empirical polynomial regression schemes.
Figure 2: Comparison among solutions for the heat equation: (a) The PINN. (b-c) The SineGEN and GaussGEN developed under the proposed GEN framework. (d-e) The temporal profiles produced at x = 0.5 (left) and x = 1.0 (right), demonstrating increasing extrapolation errors beyond the training domain ( t>2.0 ), which is particularly evident in the PINN predictions. (f-g) The 25 basis functions learned by the two GEN methods.
Figure 3: Wave equation: (a) Heatmap comparison among the numerical solution, the PINN and the two GEN results, with the colour intensities representing the solution values. (b) and (c) Temporal snapshots of the solutions produced at spatial locations x=0.5 and x=3.0 , respectively. The green shaded area represents the fitting region (training domain), and the red shaded area represents the extrapolation region.
Figure 4: Burgers’ equation: (a)-(c) Heatmap comparisons between exact solutions and GENs with various numbers of basis functions. (d)-(f) Spatial snapshots of the solutions produced at temporal positions t=0.25,0.5 and 0.75 , respectively. Magnified views near the maxima and minima are shown in the upper-right and lower-left corners, respectively. Marked fitting accuracy discrepancies are observed when a smaller number of basis functions is employed.
Neural PDE solvers use trainable models to approximate solutions or solution operators for partial differential equations, often with physical constraints.
Physics-Informed Neural Networks (PINNs) are a widely used data-free method for solving Partial Differential Equations (PDEs) using machine learning. With recent advances in Generative Adversarial Networks (GANs), adversarial learning has shown strong capabilities for modeling complex data-driven problems; however, the use of GANs in deterministic physics-informed PDE solutions remains limited. In this work, we first identify limitations of standard PINNs for solving PDEs, including spectral bias, loss imbalance, and optimizer stagnation. We then propose Generative Adversarial Physics-Informed Neural Networks (Gen-PINNs), a unified deterministic residual-adversarial framework designed to improve data-free solutions of PDEs with sharp or shock-front behavior. The generator learns the underlying PDE solution using dynamically weighted physics-informed loss components, while separate discriminators evaluate complementary PDE residual features against ideal zero-residual states. The framework further develops and adapts several methodological components, including a Fourier representation for resolving high-frequency spatial content, an orthonormal spectral diagnostic for quantifying frequency-dependent solution errors, and a modified gradient-based dynamic weighting system for physics, initial-condition, boundary-condition, and adversarial loss objectives. Gen-PINNs is tested against standard PINNs on nonlinear and higher-order PDEs, including the Burgers, Allen-Cahn, and Kuramoto-Sivashinsky equations. The results demonstrate substantial improvements in accuracy and convergence across sharp-front, stiff, and higher-order PDE solutions, highlighting the potential of deterministic residual-adversarial learning as an effective approach for solving challenging nonlinear PDEs.
Muhammad M. Akmal, Kamy Sepehrnoori, Michael J. Pyrcz
Hilderbrand Department of Petroleum and Geosystems Engineering, The University of Texas at Austin · Department of Earth and Planetary Sciences, The University of Texas at Austin
Machine learning-based partial differential equations (PDEs) solvers have attracted significant attention in recent years. Most progress in this area has been driven by deep neural networks such as physics-informed neural networks (PINNs) and kernel method (such as physics-informed Gaussian Processes). We introduce a physics-informed random feature method for countering part of the spectral bias which PINN-based solvers are facing for a certain class of PDEs. Random feature method was originally proposed to approximate large-scale kernel machines and can be viewed as a specialized randomized neural network. Compared to other state-of-the-art PINN-based solvers which require a large number of collocation points, our proposed method reduces the computational complexity. In this paper, we develop a rigorous approximation error analysis and derive high-probability error bounds on the H1 norm. We provide extensive numerical tests for verifying our theoretical guarantees on error decay rates, as well as several comparison tests to showcase our claimed capability for combating spectral bias in these deep learning based methods.
Chi-An Chen, Chunyang Liao, Ming Zhong
Department of Applied Mathematics, Mathematics, Illinois Institute of Technology, Chicago, IL, 60616 · Department of Mathematical Sciences, University of Arkansas, Fayetteville, AR, 72701 · Department of Mathematics, University of Houston, Houston, TX, 77204
The traditional limitations of neural networks in reliably generalizing beyond the convex hulls of their training data present a significant problem for computational physics, in which one often wishes to solve PDEs in regimes far beyond anything which can be experimentally or analytically validated. In this paper, we show how it is possible to circumvent these limitations by constructing formally-verified neural network solvers for PDEs, with rigorous convergence, stability, and conservation properties, whose correctness can therefore be guaranteed even in extrapolatory regimes. By using the method of characteristics to predict the analytical properties of PDE solutions a priori (even in regions arbitrarily far from the training domain), we show how it is possible to construct rigorous extrapolatory bounds on the worst-case L^inf errors of shallow neural network approximations. Then, by decomposing PDE solutions into compositions of simpler functions, we show how it is possible to compose these shallow neural networks together to form deep architectures, based on ideas from compositional deep learning, in which the large L^inf errors in the approximations have been suppressed. The resulting framework, called BEACONS (Bounded-Error, Algebraically-COmposable Neural Solvers), comprises both an automatic code-generator for the neural solvers themselves, as well as a bespoke automated theorem-proving system for producing machine-checkable certificates of correctness. We apply the framework to a variety of linear and non-linear PDEs, including the linear advection and inviscid Burgers' equations, as well as the full compressible Euler equations, in both 1D and 2D, and illustrate how BEACONS architectures are able to extrapolate solutions far beyond the training data in a reliable and bounded way. Various advantages of the approach over the classical PINN approach are discussed.
Jonathan Gorard, Ammar Hakim, James Juno
Princeton University Princeton, NJ 08544, USA · Princeton Plasma Physics Laboratory Princeton, NJ 08540, USA