A non-intrusive data-based reformulation of a hybrid projection-based model reduction method
Ion Victor Gosea, Serkan Gugercin, Christopher Beattie
TL;DR
The paper addresses non-intrusive model order reduction for large-scale LTI systems by reformulating the intrusive ISRK method into a data-driven algorithm, Quad-ISRK. It replaces explicit Gramian information with a quadrature-based Gramian approximation and constructs reduced-model data solely from transfer-function samples, preserving interpolation properties. The main contribution is a set of data-driven ROM expressions and an iterative algorithm that mirrors ISRK’s convergence behavior while avoiding access to the system matrices. Numerical results on a classical MOR benchmark show Quad-ISRK reproduces the original ISRK performance in both $H_ ext{\infty}$ and $H_2$ senses, with potential for extension to adaptive quadrature and structured/mildly nonlinear systems.
Abstract
We present a novel data-driven reformulation of the iterative SVD-rational Krylov algorithm (ISRK), in its original formulation a Petrov-Galerkin (two-sided) projection-based iterative method for model reduction combining rational Krylov subspaces (on one side) with Gramian/SVD based subspaces (on the other side). We show that in each step of ISRK, we do not necessarily require access to the original system matrices, but only to input/output data in the form of the system's transfer function, evaluated at particular values (frequencies). Numerical examples illustrate the efficiency of the new data-driven formulation.
