27th Conference of the International Linear Algebra Society (ILAS 2026)

The accuracy of the QZ algorithm and some tricks to improve it

May 18, 2026, 3:45 PM

25m

Torgersen Hall 1040 (Virginia Tech)

Minisymposium Talk Advances and Challenges in Eigensolvers Advances and Challenges in Eigensolvers

Speaker

Dr Thijs Steel (KU Leuven)

Description

For small and/or dense generalized eigenvalue problems, the QZ method remains the method of choice because of its robustness. In this talk, we will discuss how that robustness may occasionally fail, especially if the matrices are badly scaled or singular. We will discuss how new deflation criteria and some changes in the preprocessing can improve the robustness.