PGD-based local surrogate models via overlapping domain decomposition: a computational comparison

TL;DR

This paper introduces a PGD-based local surrogate modeling approach with overlapping domain decomposition for parametric elliptic problems, achieving significant computational speed-ups and efficient real-time evaluations.

Contribution

It presents a novel non-intrusive PGD-based local surrogate model combined with an overlapping domain decomposition and algebraic Schwarz method, enhancing efficiency and speed.

Findings

Speed-ups up to 100 times compared to previous methods

Real-time evaluation in less than half a second

Superior performance demonstrated through numerical benchmarks

Abstract

An efficient strategy to construct physics-based local surrogate models for parametric linear elliptic problems is presented. The method relies on proper generalized decomposition (PGD) to reduce the dimensionality of the problem and on an overlapping domain decomposition (DD) strategy to decouple the spatial degrees of freedom. In the offline phase, the local surrogate model is computed in a non-intrusive way, exploiting the linearity of the operator and imposing arbitrary Dirichlet conditions, independently at each node of the interface, by means of the traces of the finite element functions employed for the discretization inside the subdomain. This leads to parametric subproblems with reduced dimensionality, significantly decreasing the complexity of the involved computations and achieving speed-ups up to 100 times with respect to a previously proposed DD-PGD algorithm that required clustering the interface nodes. A fully algebraic alternating Schwarz method is then formulated to couple the subdomains in the online phase, leveraging the real-time (less than half a second) evaluation capabilities of the computed local surrogate models, that do not require the solution of any additional low-dimensional problems. A computational comparison of different PGD-based local surrogate models is presented using a set of numerical benchmarks to showcase the superior performance of the proposed methodology, both in the offline and in the online phase.