Estimating Penalized Functional Linear Regression

Implementation of commonly used penalized functional linear regression models, including the Smooth and Locally Sparse (SLoS) method by Lin et al. (2016) , Nested Group bridge Regression (NGR) method by Guan et al. (2020) , Functional Linear Regression That's interpretable (FLIRTI) by James et al. (2009) , and the Penalized B-spline regression method.