The kernel independent component analysis (kernel ICA) method introduced by Bach and Jordan in 2002 (see references). The incomplete Cholesky decomposition used in kernel ICA is provided as separate function.
Francis R. Bach, Michael I. Jordan Kernel independent component analysis Journal of Machine Learning Research 2002 10.1162/153244303768966085
Francis R. Bach, Michael I. Jordan Predictive low-rank decomposition for kernel methods. Proceedings of the Twenty-second International Conference on Machine Learning (ICML) 2005 10.1145/1102351.1102356.
Sean Martin, Andrew M. Raim, Wen Huang, Kofi P. Adragni ManifoldOptim: An R Interface to the ROPTLIB Library for Riemannian Manifold Optimization Journal of Statistical Software 2020 10.18637/jss.v093.i01