Category "cubic-spline"

Is there a function for not-a-knot cubic splines?

I need to use the "not-a-knot" cubic spline for interpolation in my R scripts. Although there are some R packages for splines, none of them seem to consider th

(Cubic) spline interpolation

I want to perform a (cubic) spline interpolation for population data to "transform" yearly data into quarterly data. I know that there are a fair number of flaw