CV and GCV for finding smoothness parameter
`gam' in package `mgcv' will let you supply any smoothing parameter you want (via argument `sp') and will get the fit and corresponding GCV score for you (`gcv.ubre' in the `gam' object). The CV score you'd have to calculate yourself, but `influence.gam' will extract the necessary H_ii. See the examples in ?smooth.construct for how to use the truncated polynomial basis with mgcv:gam.
On Tuesday 31 March 2009 15:22, Nora Velvet wrote:
I received an assignment that I have to do in R, but I'm absolutely not very good at it. The task is the following: http://www.nabble.com/file/p22804957/question8.jpg To do this, we also get the following pieces of code (not in correct order): http://www.nabble.com/file/p22804957/hints.jpg I'm terrible at this and I'm completely stuck. The model I chose can be found in here: myknots6 = c(20,24,34) p.spline8 = spm(accel ~ f(times,basis="trunc.poly",degree=2,knots=myknots6)) Can someone please help me with this task? I'm kind of desperate. Thank you!
> Simon Wood, Mathematical Sciences, University of Bath, Bath, BA2 7AY UK > +44 1225 386603 www.maths.bath.ac.uk/~sw283