A Posteriori Single- and Multi-Goal Error Control and Adaptivity for Partial Differential Equations
Bernhard Endtmayer, Ulrich Langer, Thomas Richter, Andreas Schafelner, Thomas Wick
TL;DR
The paper develops and surveys a posteriori, goal-oriented error estimation for PDEs using the dual-weighted residual method with partition-of-unity localization, extending from single- to multi-goal functionals. It introduces enriched- and interpolated-space estimators to obtain computable, efficient, and reliable error indicators, along with strategies to balance discretization and nonlinear iteration errors. A key theoretical advance is a saturation-based efficiency/reliability framework that requires only one saturation assumption, plus detailed treatment of non-standard discretizations and non-conforming methods. The approach is validated through Poisson, nonlinear elliptic, stationary Navier–Stokes, and space-time parabolic p-Laplace applications, with open-source implementations to support reproduction and further development. The results underscore the practical impact of space-time multigoal adaptivity for complex multiphysics problems and guide future work on extending error estimators to additional error sources and model-order reductions.
Abstract
This work reviews goal-oriented a posteriori error control, adaptivity and solver control for finite element approximations to boundary and initial-boundary value problems for stationary and non-stationary partial differential equations, respectively. In particular, coupled field problems with different physics may require simultaneously the accurate evaluation of several quantities of interest, which is achieved with multi-goal oriented error control. Sensitivity measures are obtained by solving an adjoint problem. Error localization is achieved with the help of a partition-of-unity. We also review and extend theoretical results for efficiency and reliability by employing a saturation assumption. The resulting adaptive algorithms allow to balance discretization and non-linear iteration errors, and are demonstrated for four applications: Poisson's problem, non-linear elliptic boundary value problems, stationary incompressible Navier-Stokes equations, and regularized parabolic $p$-Laplace initial-boundary value problems. Therein, different finite element discretizations in two different software libraries are utilized, which are partially accompanied with open-source implementations on GitHub.
