activity
19982026
most citedA framework for deflated and augmented Krylov subspace methods

74 citations · 77 across the 8 of their papers we have counts for

collaborators

10 papers

math.RA2026

Inverse acyclic Z-matrices, matrices of tree structure and shifted generalized ultrametric matrices

Reinhard Nabben

Inverses of acyclic or treediagonal matrices are nicely characterized in the landmarked paper by Klein \cite{KLe82}. But also in \cite{Nab01} a characterization of these inverses i…

math.RA2026

Hidden decay in the inverses of acyclic matrices

Reinhard Nabben

It is well-known that the absolute values of the entries of the inverse of a diagonally dominant tridiagonal matrix decay away from the diagonal. Moreover, lower and upper bounds f…

math.NA2026

Norm-based convergence bounds for nonsymmetric algebraic V-cycle multigrid methods

Reinhard Nabben, Ludwig Rooch

Recently a new approach to analyze and create algebraic multigrid methods (AMG) for nonsymmetric and indefinite matrices was established. Convergence is measured in general norms i…

math.NA2026

Optimal transfer operators for nonsymmetric two-grid methods

Reinhard Nabben, Ludwig Rooch

Algebraic Multigrid (AMG) methods have been proven to be effective solvers for large-scale linear algebraic systems with Hermitian positive definite (HPD) matrix . For…

math.NA2025

Factorized sparse approximate inverse preconditioning for singular M-matrices

Katherina Bick, Reinhard Nabben

Here we consider the factorized sparse approximate inverse (FSAI) preconditioner. We apply the FSAI preconditioner to singular irreducible M-matrices. These matrices arise e.g. in…

math.NA2020★ 1 cited

A two-level shifted Laplace preconditioner for Helmholtz problems: Field-of-values analysis and wavenumber-independent convergence

Luis García Ramos, Reinhard Nabben

One of the main tools for solving linear systems arising from the discretization of the Helmholtz equation is the shifted Laplace preconditioner, which results from the discretizat…