[R] How to generate natural cubic spline in R?
Stephan Kolassa
Stephan.Kolassa at gmx.de
Tue Mar 31 12:09:00 CEST 2009
Hi,
if you are looking for *natural* cubic splines (linear beyond the outer
knots), you could use rcs() in Frank Harrell's Design package.
HTH,
Stephan
David Winsemius schrieb:
> If one enters:
>
> ??"spline"
>
> ... You get quite a few matches. The one in the stats functions that
> probably answers your specific questions is:
>
> "splinefun {stats} R Documentation
> Interpolating Splines Description
> Perform cubic (or Hermite) spline interpolation of given data points,
> returning either a list of points obtained by the interpolation or a
> function performing the interpolation."
>
> "splinefun returns a function with formal arguments x and deriv, the
> latter defaulting to zero. This function can be used to evaluate the
> interpolating cubic spline (deriv=0), or its derivatives (deriv=1,2,3)
> at the points x, where the spline function interpolates the data points
> originally specified. This is often more useful than spline."
>
> Perhaps you need to review from you basic intro material regarding
> help.search("text") # or
> ??"text" # possibilities.
>
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