b_rcs: Basis for restricted cubic splines
Description
Function that derives the restricted cubic splines
for a value/vector of values, given the knots;
obtains exactly the same results as the rcs function included in the rms package.
Usage
b_rcs(x, knots, inclx = FALSE)
Arguments
knots
vector specifying the knot locations
inclx
logical, if TRUE returns also the x vector