English

Comparing the Methods of Alternating and Simultaneous Projections for Two Subspaces

Optimization and Control 2023-11-15 v2

Abstract

We study the well-known methods of alternating and simultaneous projections when applied to two nonorthogonal linear subspaces of a real Euclidean space. Assuming that both of the methods have a common starting point chosen from either one of the subspaces, we show that the method of alternating projections converges significantly faster than the method of simultaneous projections. On the other hand, we provide examples of subspaces and starting points, where the method of simultaneous projections outperforms the method of alternating projections.

Keywords

Cite

@article{arxiv.2306.12219,
  title  = {Comparing the Methods of Alternating and Simultaneous Projections for Two Subspaces},
  author = {Simeon Reich and Rafał Zalas},
  journal= {arXiv preprint arXiv:2306.12219},
  year   = {2023}
}
R2 v1 2026-06-28T11:10:40.743Z