[R] Fwd: Re[2]: B-spline/smooth.basis derivative matrices

[Vassily Shvets]

--- On Mon, 3/12/12, aleksandr shfets <a_shfets at mail.ru> wrote:

> From: aleksandr shfets <a_shfets at mail.ru>
> Subject: Fwd: Re[2]: [R] B-spline/smooth.basis derivative matrices
> To: "Vassily Shvets" <shv736 at yahoo.com>
> Received: Monday, March 12, 2012, 5:15 PM
> 
> 
> 
> -------- Пересылаемое сообщение
> --------
> От кого: aleksandr shfets <a_shfets at mail.ru>
> Кому: vito.muggeo <vito.muggeo at unipa.it>
> Дата: 13 марта 2012, 03:09
> Тема: Re[2]: [R] B-spline/smooth.basis derivative
> matrices
> 
> 
> Hello again,(my message was truncated the first time!)
> 
> Thank you, vito for these functions: I've been able to look
> at the smoothing spline matrix and its derivatives that I
> constucted with functions "create.bspline.basis" and
> "smooth.basis"
> 
> Understanding from Hastie and Tishbirani that the
> S(lambda)-- the penalty matrix
> 
> decreases in magnitude compared to the matrix [y[i,j] -
> f(x)] would it not be of fundamental importance to
> 
> have the penalty matrix be the same magnitude?
> 
> That is to get both matrices in the smooth, i.e,
> 
> SS(f, λ) =[y − f(x)]^2 + λ*int(x1,x2)[[f''(x)]^2 dx
> 
> to the same size?
> 
> Especially if one is working with an  R
> program(CollocInfer) that will only evaluate yhat =X*beta
> with appropriate matrices?
> 
> regards,
> s
> I hope I don't ask a question whose answer is evident;I
> haven't been able to see an answer to this question-- how to
> coerce the matrices to be the same size-- from the data
> sources I've been able to access.
> 
> 25 февраля 2012, 15:11 от "vito.muggeo" <vito.muggeo at unipa.it>:
> > dear s,
> >
> > If you are willing to use B-splines placing p knots,
> say, (rather than smoothing splines
> > placing n knots), you could have a look to the
> functions splineDesign() or spline.des()
> > (argument derivs) in the package "splines".
> >
> > vito
> >
> > On Fri, 24 Feb 2012 12:28:58 -0800 (PST), Vassily
> Shvets wrote
> > > Hello,
> > > I've noticed that SPLUS seems to have a function
> for evaluating derivative
> > > matrices of splines. I've found the R function
> that evaluates matrices from
> > > 'smooth.spline'; maybe someone has written
> something to do the same with smooth.basis?
> > > regards,
> > > s
> > >
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> ----------------