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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.

A Posteriori Single- and Multi-Goal Error Control and Adaptivity for Partial Differential Equations

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 -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.
Paper Structure (81 sections, 17 theorems, 185 equations, 31 figures, 10 tables, 3 algorithms)

This paper contains 81 sections, 17 theorems, 185 equations, 31 figures, 10 tables, 3 algorithms.

Key Result

Theorem 1

Let $\tilde{u} \in U$ and $\tilde{z} \in V$ be arbitrary but fixed, and let $u \in U$ be the solution of the model problem eq: General Modelproblem, and $z \in V$ be the solution of the adjoint problem eq: General Adjointproblem. If $\mathcal{A} \in \mathcal{C}^3(U,V^*)$ and $J \in \mathcal{C}^3(U,\ for arbitrary but fixed $\tilde{u} \in U$ and $\tilde{z} \in V$, where and the remainder term wit

Figures (31)

  • Figure 1: Visualization of how the degrees of freedom are interpolated on elements of higher order with a coarser grid for $Q_1$ finite elements.
  • Figure 2: Visualization of how the degrees of freedom are interpolated on elements of higher order with a coarser grid for $P_1$ finite elements.
  • Figure 3: Nodal error estimator on the hanging $\eta_5$ is distributed equally to $\eta_3$ and $\eta_5$ the nodal contribution is distributed to the elements.
  • Figure 4: Example 1: Going from left to right and top to bottom: error indicators, adaptive mesh, primal solution and adjoint solution.
  • Figure 5: Example 2: Initial mesh with quantities of interest (left), and adaptively refined mesh after 25 refinement steps driven by the combined functional $J_\mathfrak{E}$ (right).
  • ...and 26 more figures

Theorems & Definitions (43)

  • Theorem 1: see RanVi2013EnLaWi18
  • proof
  • Remark 1
  • Theorem 2: see endtmayer2023goal
  • proof
  • Remark 2
  • Definition 1: Efficient and Reliable
  • Theorem 3
  • proof
  • Theorem 4
  • ...and 33 more