How to generate natural cubic spline in R?
David Winsemius wrote:
The splinefun documentation indicates that "natural" is one of the types of cubic spline options available. Does rcs actually do fitting? Such would not be my expectation on reading the documentation and I do not see any examples of such functionality in the help pages.
It expands a predictor into the truncated power basis functions for the natural cubic spline. This is an easier basis to use than the B-spline basis. rcs calls the Hmisc function rcspline.eval which you may want to look at first. Frank
Frank E Harrell Jr Professor and Chair School of Medicine
Department of Biostatistics Vanderbilt University