[R] need help with smooth.spline

W. C. Thacker Carlisle.Thacker at noaa.gov
Fri Mar 5 20:03:23 CET 2004


"Liaw, Andy" wrote:
> 
> I looked at rqss() in nprq, as Prof. Koenker suggested, but that doesn't
> have a predict() method, so I don't know how you'd get the smooth at values
> other than the observed...
> 
> The criteria (CV, GCV, etc.) could have multiple local minima for some data,
> as Prof. Ripley and Prof. Koenker pointed out, so relying on those
> `automatic' selection procedure may not be the best thing to do.
> Theoretically as spar (lambda) goes to 0, smooth.spline should linearly
> interpolate the data.  I guess the routine could run into numerical problems
> before that.
> 
> Here's yet another thing to try (thanks to Martin for the `lokern' package):
> 
> library(lokerns)
> par(mfrow=c(2,4))
> for (i in 1:4) {
>   plot(dat[[i]]$p, dat[[i]]$t);
>   lines(lokerns(dat[[i]]$p, dat[[i]]$t, x.out=seq(25,1000,25)))
>   plot(dat[[i]]$p, dat[[i]]$s)
>   lines(lokerns(dat[[i]]$p, dat[[i]]$s, x.out=seq(25,1000,25)))
> }
> 
> Best,
> Andy

Thanks for still another suggestion.  I'm keeping our system manager
busy loading packages.  Is there a way he can get them all at once?

Also, do you know whether any of these packages come with a manual ---
other than the help pages?

Regards,

Carlisle




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