3 papers
math.NA2026
An new polar factor retraction on the Stiefel manifold with closed-form inverse
Rasmus Jensen, Ralf Zimmermann
Retractions are the workhorses in Riemannian computing applications, where computational efficiency is of the essence. This work introduces a new retraction on the compact Stiefel…
math.NA2025
Maximum volume coordinates for Grassmann interpolation: Lagrange, Hermite, and errors
Rasmus Jensen, Ralf Zimmermann
We present a novel approach to Riemannian interpolation on the Grassmann manifold. Instead of relying on the Riemannian normal coordinates, i.e. the Riemannian exponential and loga…
math.NA2024
Riemannian optimization on the symplectic Stiefel manifold using second-order information
Rasmus Jensen, Ralf Zimmermann
Riemannian optimization is concerned with problems, where the independent variable lies on a smooth manifold. There is a number of problems from numerical linear algebra that fall…