Statistical reduced order modelling for the parametric Helmholtz equation

TL;DR

This paper introduces a statistical reduced order modeling framework for the parametric Helmholtz equation that improves accuracy and efficiency by explicitly accounting for reduced model bias using Krylov-based moment matching.

Contribution

It presents a novel statistical reduced order model for the Helmholtz equation that explicitly estimates and incorporates bias, enhancing predictive accuracy and computational speed.

Findings

Better accuracy compared to standard statFEM

Faster convergence across frequency ranges

Effective bias estimation with inexpensive error indicator

Abstract

Predictive modeling involving simulation and sensor data at the same time, is a growing challenge in computational science. Even with large-scale finite element models, a mismatch to the sensor data often remains, which can be attributed to different sources of uncertainty. For such a scenario, the statistical finite element method (statFEM) can be used to condition a simulated field on given sensor data. This yields a posterior solution which resembles the data much better and additionally provides consistent estimates of uncertainty, including model misspecification. For frequency or parameter dependent problems, occurring, e.g. in acoustics or electromagnetism, solving the full order model at the frequency grid and conditioning it on data quickly results in a prohibitive computational cost. In this case, the introduction of a surrogate in form of a reduced order model yields much smaller systems of equations. In this paper, we propose a reduced order statFEM framework relying on Krylov-based moment matching. We introduce a data model which explicitly includes the bias induced by the reduced approximation, which is estimated by an inexpensive error indicator. The results of the new statistical reduced order method are compared to the standard statFEM procedure applied to a ROM prior, i.e. without explicitly accounting for the reduced order bias. The proposed method yields better accuracy and faster convergence throughout a given frequency range for different numerical examples.