Основні поняття
This paper compares two numerical methods for integrating Riemannian cubic polynomials on the Stiefel manifold: the adjusted de Casteljau algorithm and a symplectic integrator constructed through discretization maps. The authors provide a numerical comparison of the two methods and discuss the benefits of each approach.
Анотація
The paper focuses on comparing two numerical methods for generating Riemannian cubic polynomials on Stiefel manifolds:
- The adjusted de Casteljau algorithm, which uses quasi-geodesics to modify the standard de Casteljau algorithm for Riemannian manifolds.
- A symplectic integrator constructed through discretization maps, which provides a numerical scheme for approximating the Hamiltonian flow associated with Riemannian cubic polynomials.
The authors consider two specific cases: the Stiefel manifold St3,1, which is diffeomorphic to the sphere, and the Stiefel manifold St3,2, which has a pure quasi-geodesic different from a geodesic.
The key findings are:
- The adjusted de Casteljau algorithm provides a reasonably good approximation of the Riemannian cubic polynomials, with relative mean errors around 0.08% for the sphere and 0.45% for St3,2.
- The retraction-based symplectic integrators have an error that decreases as the time step is reduced, making them suitable for simulating dynamics near the initial point.
- Retraction-based integrators require more computational effort than the adjusted de Casteljau algorithm, but can achieve higher accuracy.
- The adjusted de Casteljau algorithm is better suited for solving boundary value problems, while the retraction-based methods are more suitable for initial value problems.
The authors discuss the trade-offs between the two methods and suggest future research directions, such as improving the performance of retraction-based integrators by exploiting the geometric structure of the manifold.
Статистика
The paper provides the following key figures and statistics:
Relative mean error of the adjusted de Casteljau algorithm: 0.08% for the sphere, 0.45% for St3,2
Comparison of mean error between the adjusted de Casteljau algorithm and retraction-based symplectic integrators for the sphere and St3,2
Цитати
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