HyPINO: Multi-Physics Neural Operators via HyperPINNs and the Method of Manufactured Solutions

1Computational Design Lab, ETH Zurich, Switzerland 2Institute of Structural Mechanics and Design, TU Darmstadt, Germany 3Seminar for Applied Mathematics, ETH Zurich, Switzerland
NeurIPS 2025 Spotlight

Abstract

We present HyPINO, a multi-physics neural operator designed for zero-shot generalization across a broad class of PDEs without requiring task-specific fine-tuning. Our approach combines a Swin Transformer-based hypernetwork with mixed supervision: (i) labeled data from analytical solutions generated via the Method of Manufactured Solutions (MMS), and (ii) unlabeled samples optimized using physics-informed objectives. The model maps PDE parameterizations to target Physics-Informed Neural Networks (PINNs) and can handle linear elliptic, hyperbolic, and parabolic equations in two dimensions with varying source terms, geometries, and mixed Dirichlet/Neumann boundary conditions, including interior boundaries. HyPINO achieves strong zero-shot accuracy on seven benchmark problems from PINN literature, outperforming U-Nets, Poseidon, and Physics-Informed Neural Operators (PINO). Further, we introduce an iterative refinement procedure that treats the residual of the generated PINN as “delta PDE” and performs another forward pass to generate a corrective PINN. Summing their contributions and repeating this process forms an ensemble whose combined solution progressively reduces the error on six benchmarks and achieves a >100× lower L2 loss in the best case, while retaining forward-only inference. Additionally, we evaluate the fine-tuning behavior of PINNs initialized by HyPINO and show that they converge faster and to lower final error than both randomly initialized and Reptile-meta-learned PINNs on five benchmarks, performing on par on the remaining two. Our results highlight the potential of this scalable approach as a foundation for extending neural operators toward solving increasingly complex, nonlinear, and high-dimensional PDE problems. The code and model weights are publicly available at https://github.com/rbischof/hypino.
arXiv Paper
Web Demo
Medium Article

HyPINO is a multi-physics neural operator framework that generalizes across diverse linear, 2D, second-order PDEs in a zero-shot manner.
It uses a Swin Transformer–based hypernetwork to generate Physics-Informed Neural Networks (PINNs) conditioned on PDE specifications, trained entirely using the Method of Manufactured Solutions (MMS). This repository contains the official implementation of the paper.

Features

  • Zero-shot generalization across linear, 2D, second-order PDE families (elliptic, parabolic, hyperbolic)
  • Mixed boundary condition support: Dirichlet, Neumann, and interior boundaries
  • Swin Transformer hypernetwork that generates task-specific PINNs
  • Residual-based iterative refinement for test-time accuracy improvement
  • PINN initialization for faster convergence and improved fine-tuning performance

Framework Overview

As an example, consider the Poisson equation $-\Delta u(x, y) = 0$, defined on a square domain with circular inner boundaries.
The image below shows the input fields expected by HyPINO and their corresponding reference solutions.

Given a PDE specification, HyPINO’s Swin Transformer hypernetwork generates the weights of a target PINN, which can be evaluated continuously over the spatial domain $(x, y) \in [-1, 1]^2$.

Citation

				
					@ARTICLE{2025arXiv250905117B,
       author = {{Bischof}, Rafael and {Piovar{\v{c}}i}, Michal and {Kraus}, Michael A. and {Mishra}, Siddhartha and {Bickel}, Bernd},
        title = "{HyPINO: Multi-Physics Neural Operators via HyperPINNs and the Method of Manufactured Solutions}",
      journal = {arXiv e-prints},
     keywords = {Machine Learning},
         year = 2025,
        month = sep,
          eid = {arXiv:2509.05117},
        pages = {arXiv:2509.05117},
          doi = {10.48550/arXiv.2509.05117},
archivePrefix = {arXiv},
       eprint = {2509.05117},
 primaryClass = {stat.ML},
       adsurl = {https://ui.adsabs.harvard.edu/abs/2025arXiv250905117B},
      adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}