[R] cubic spline

[David Winsemius]

On Dec 1, 2012, at 5:09 AM, Steve Stephenson wrote:

> Hallo,
> I'm facing a problem and I would really appreciate your support.
> I have to translate some Matalb code in R that I don't know very  
> well but I
> would like to.
> I have to interpolate 5 point with a cubic spline function and then  
> I expect
> my function returns the Y value as output a specific X value inside  
> the
> evaluation range.  Let's suppose that:
>  1-  *X = [-10, -5, 0, 5, 10]*
>  2 - *Y = [12, 10, 8, 7, 6]*
>  3 - *I have to interpolate with a cubic spline assuming x=11*
>
> In Matlab I used this function:
>
> *y = interp1(X, Y, x, "cubic"); *
>
> How can I do the same in R?
> Many thanks in advance for your reply and support!

splinefun( x = c(-10, -5, 0, 5, 10),
            y = c(12, 10, 8, 7, 6),
          method="natural")(11)
[1] 5.785714

-- 
David Winsemius, MD
Alameda, CA, USA