Multilayer approximate nullspace methods for saddle point systems

MANGUOĞLU M., Mehrmann V.

Linear Algebra and Its Applications, 2026 (SCI-Expanded, Scopus) identifier

  • Publication Type: Article / Article
  • Publication Date: 2026
  • Doi Number: 10.1016/j.laa.2026.02.008
  • Journal Name: Linear Algebra and Its Applications
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, MathSciNet, zbMATH
  • Keywords: Approximate nullspace method, Multi-layer iterative method, Saddle point matrix
  • Middle East Technical University Affiliated: Yes

Abstract

We propose a new class of multi-layer iterative schemes for solving sparse linear systems in saddle point structure. The new scheme consists of an iterative preconditioner that is based on the (approximate) nullspace method, combined with an iterative least squares approach and an iterative projection method. We present a theoretical analysis and demonstrate the effectiveness and robustness of the new scheme on sparse matrices from various applications.