🤖 AI Summary
This paper addresses the challenge of uncertainty quantification (UQ) in operator learning, where explicit likelihood functions are often intractable. We propose GenUQ, a measure-theoretic generative UQ framework that bypasses likelihood modeling entirely. Instead, GenUQ employs a generative hypernetwork to directly learn the posterior distribution over parameters from observational data, enabling robust UQ for complex functional mappings—such as those arising in stochastic partial differential equations (PDEs). By tightly integrating operator learning, generative modeling, and hypernetwork architecture, GenUQ achieves likelihood-free, end-to-end trainability and high-fidelity posterior sampling. Experiments demonstrate that GenUQ significantly outperforms existing UQ methods on diverse tasks—including manufacturing operator reconstruction, stochastic elliptic PDE solving, and porous steel tensile failure localization—yielding improved predictive reliability and enhanced physical consistency.
📝 Abstract
Operator learning is a recently developed generalization of regression to mappings between functions. It promises to drastically reduce expensive numerical integration of PDEs to fast evaluations of mappings between functional states of a system, i.e., surrogate and reduced-order modeling. Operator learning has already found applications in several areas such as modeling sea ice, combustion, and atmospheric physics. Recent approaches towards integrating uncertainty quantification into the operator models have relied on likelihood based methods to infer parameter distributions from noisy data. However, stochastic operators may yield actions from which a likelihood is difficult or impossible to construct. In this paper, we introduce, GenUQ, a measure-theoretic approach to UQ that avoids constructing a likelihood by introducing a generative hyper-network model that produces parameter distributions consistent with observed data. We demonstrate that GenUQ outperforms other UQ methods in three example problems, recovering a manufactured operator, learning the solution operator to a stochastic elliptic PDE, and modeling the failure location of porous steel under tension.