This brief describes the basics of Riemannian optimization--optimization
on Riemannian manifolds--introduces algorithms for Riemannian
optimization problems, discusses the theoretical properties of these
algorithms, and suggests possible applications of Riemannian
optimization to problems in other fields.
To provide the reader with a smooth introduction to Riemannian
optimization, brief reviews of mathematical optimization in Euclidean
spaces and Riemannian geometry are included. Riemannian optimization is
then introduced by merging these concepts. In particular, the Euclidean
and Riemannian conjugate gradient methods are discussed in detail. A
brief review of recent developments in Riemannian optimization is also
provided.
Riemannian optimization methods are applicable to many problems in
various fields. This brief discusses some important applications
including the eigenvalue and singular value decompositions in numerical
linear algebra, optimal model reduction in control engineering, and
canonical correlation analysis in statistics.