An R Interface to the 'ROPTLIB' Library for Riemannian Manifold Optimization

An R interface to version 0.3 of the 'ROPTLIB' optimization library (see < https://www.math.fsu.edu/~whuang2/> for more information). Optimize real- valued functions over manifolds such as Stiefel, Grassmann, and Symmetric Positive Definite matrices. For details see Martin et. al. (2020) . Note that the optional ldr package used in some of this package's examples can be obtained from either JSS < https://www.jstatsoft.org/index.php/jss/article/view/v061i03/2886> or from the CRAN archives < https://cran.r-project.org/src/contrib/Archive/ldr/ldr_1.3.3.tar.gz>.