Pspline smoothing
On Mon, 25 Nov 2002, Martin Renner wrote:
I'm trying to use the Pspline add-on package to fit a quintic spline (norder =3), but I keep running into a Singularity error.
traj.spl <- smooth.Pspline(time, x, norder=3 )
Error in smooth.Pspline(time, x, norder = 3) : Singularity error in solving equations
time <- 1:100 x <- rnorm(100) traj.spl <- smooth.Pspline(time, x, norder=3 ) works for me. It's probably something specific to your data. However, the defaults spar=0, method=1 are not sensible: they are asking for a perfect fit. At least try method=3.
Playing around with the other parameters produces an "unused arguments" error:
traj.spl <- smooth.Pspline(time, x, norder=3 , cv=FALSE, method=3)
Error in smooth.Pspline(time, x, norder = 3, cv = FALSE, method = 3) : unused argument(s) (cv ...)
?smooth.Pspline does not have argument cv listed for smooth.Pspline, so no wonder it does not work.
Setting norder=2 doesn't produce an error but summary indicates norder=1.
traj.spl <- sm.spline (time,x, norder=2, cv=FALSE) summary (traj.spl)
Length Class Mode norder 1 -none- numeric x 36 -none- numeric ysmth 36 -none- numeric lev 36 -none- numeric gcv 1 -none- numeric cv 1 -none- numeric df 1 -none- numeric spar 1 -none- numeric call 6 -none- call
That's *length* 1, not value 1. It's also sm.spline not smooth.Pspline. I suspect that if you read the help page accurately you can find ways to do what you want. I suggest starting with the defualt settings of sm.spline until you understand those of smooth.Pspline.
Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._