DeepXDE: A Deep Learning Library for Solving Differential Equations
Lu LuXuhui MengZhiping MaoGeorge E. Karniadakis
Introduces DeepXDE, a Python library for physics-informed neural networks that solves forward and inverse differential equations on complex geometries using residual-based adaptive refinement.
Traditional numerical methods for solving differential equations—such as finite element and finite difference techniques—often struggle with high-dimensional systems, complex mesh generation, and inverse problems where physical parameters must be inferred from observed data. In response, the emerging field of Scientific Machine Learning combines scientific computing with artificial intelligence. The article evaluates the capabilities of Physics-Informed Neural Networks and introduces DeepXDE, an open-source Python library designed to simplify the implementation of deep learning solvers for forward and inverse scientific problems.
The authors assess the framework by embedding physical laws—specifically governing differential equations and boundary conditions—directly into the loss function of a deep neural network using automatic differentiation. To evaluate accuracy, flexibility, and computational efficiency, the authors tested the platform across five benchmark computational science problems: an elliptic equation on an irregular L-shaped domain, one- and two-dimensional nonlinear transport problems, a chaotic dynamic system, a porous media chemical reaction model, and an integro-differential equation. The study also introduced a Residual-Based Adaptive Refinement technique to improve training efficiency by dynamically placing residual evaluation points in regions with high modeling errors.
The findings confirm that this deep learning framework accurately and robustly solves both forward and inverse differential problems. First, in parameter identification tasks, the framework accurately recovered physical constants with minimal error, determining chaotic system parameters to within 0.02% to 0.08% of their true values and recovering reaction rates and diffusion coefficients from observation data. Second, the proposed adaptive refinement method substantially outperformed standard random point sampling, effectively capturing sharp moving fronts and steep gradients in fluid transport models with very few added residual points. Third, the framework successfully solved integro-differential equations with an error margin of approximately 0.2% by pairing neural network representations with classical numerical quadrature. Fourth, unlike standard function approximation where networks learn low frequencies before high frequencies, physics-informed neural networks were observed to learn multiple frequency components simultaneously due to the presence of derivative constraints.
These results demonstrate that deep learning solvers provide a flexible, mesh-free alternative to traditional engineering simulations, eliminating the time-consuming geometric meshing pipeline through constructive solid geometry. Crucially, the platform enables engineers to solve complex inverse parameter estimation problems with almost the exact same codebase as forward simulations, dramatically reducing development effort and software complexity when assimilating experimental or field measurements.
Organizations evaluating this approach should consider deploying deep learning solvers particularly for inverse modeling, multi-physics integration, and scenarios involving noisy experimental data. However, traditional numerical methods currently remain faster for standard forward simulations; therefore, teams should explore hybrid workflows or offline model pre-training. Further research is recommended to automate network architecture selection through meta-learning and expand geometric capabilities to curvilinear boundaries. Decision-makers should also note that physics-informed neural networks solve non-convex optimization problems, meaning solutions lack the formal uniqueness and deterministic error bounds inherent to classical linear solvers, requiring hyperparameter tuning and multi-initialization verification across operational deployments.
- Paper: Learning nonlinear operators via DeepONet based on the universal approximation theorem of operators, Lu Lu et al. (2021). Reading DeepONet first provides essential context on operator learning foundations that directly inform DeepXDE's approach to approximating solution maps for differential equations.
- Paper: Fourier Neural Operator for Parametric Partial Differential Equations, Zongyi Li et al. (2020). Understanding Fourier neural operators is prerequisite for grasping how modern mesh-invariant architectures build upon and extend the physics-informed neural network frameworks implemented in DeepXDE.
- Paper: Automatic differentiation in machine learning: a survey, Atilim Gunes Baydin et al. (2018). A firm grounding in automatic differentiation is critical because DeepXDE relies fundamentally on derivative computations through backpropagation to embed governing differential equations into neural network loss functions.
- Paper: KAN: Kolmogorov-Arnold Networks, Ziming Liu et al. (2025). Building directly on DeepXDE's foundational PDE-solving paradigm, this work applies Kolmogorov-Arnold Networks to achieve significantly higher interpretability and parameter efficiency when solving differential equations.
- Paper: Implicit Neural Representations with Periodic Activation Functions, Vincent Sitzmann et al. (2020). Extending beyond standard multilayer perceptrons used in early DeepXDE models, this paper introduces periodic activation functions that dramatically improve derivative accuracy for solving complex partial differential equations.
