activity
20222026
most citedA pollution-free ultra-weak FOSLS discretization of the Helmholtz equation

1 citations · 2 across the 7 of their papers we have counts for

collaborators

8 papers

math.NA2026

Model reduction of port-Hamiltonian systems via neural networks

Silke Glas, Alexander Heinlein, Harald Monsuur +1

In this paper, we consider structure-preserving model reduction of port-Hamiltonian (pH) systems which extend classical Hamiltonian systems with dissipation and an input-output por…

math.NA2025

A least squares finite element method for backward parabolic problems

Harald Monsuur

Backward parabolic equations, such as the backward heat equation, are classical examples of ill-posed problems where solutions may not exist or depend continuously on the data. In…

math.NA2025

Preconditioning of a pollution-free discretization of the Helmholtz equation

Harald Monsuur

We present a pollution-free first order system least squares (FOSLS) formulation for the Helmholtz equation, solved iteratively using a block preconditioner. This preconditioner co…

math.NA2024

Quasi-Optimal Least Squares: Inhomogeneous boundary conditions, and application with machine learning

Harald Monsuur, Robin Smeets, Rob Stevenson

We construct least squares formulations of PDEs with inhomogeneous essential boundary conditions, where boundary residuals are not measured in unpractical fractional Sobolev norms,…

math.NA2024

Ultra-weak least squares discretizations for unique continuation and Cauchy problems

Harald Monsuur, Rob Stevenson

In this paper, conditional stability estimates are derived for unique continuation and Cauchy problems associated to the Poisson equation in ultra-weak variational form. Numerical…

math.NA2023★ 1 cited

A pollution-free ultra-weak FOSLS discretization of the Helmholtz equation

Harald Monsuur, Rob Stevenson

We consider an ultra-weak first order system discretization of the Helmholtz equation. When employing the optimal test norm, the `ideal' method yields the best approximation to the…

math.NA2023

Minimal residual methods in negative or fractional Sobolev norms

Harald Monsuur, Rob Stevenson, Johannes Storn

For numerical approximation the reformulation of a PDE as a residual minimisation problem has the advantages that the resulting linear system is symmetric positive definite, and th…

math.NA2022★ 1 cited

Least squares solvers for ill-posed PDEs that are conditionally stable

Wolfgang Dahmen, Harald Monsuur, Rob Stevenson

This paper is concerned with the design and analysis of least squares solvers for ill-posed PDEs that are conditionally stable. The norms and the regularization term used in the le…