predict in Pspline package (PR#2714)
There is a pspline package, but no Pspline package. I presume you mean *pspline*, and have no idea how library(Pspline) would work. For *pspline* your example works correctly on Linux, Solaris and Windows, so the problem is definitely with your installation (and perhaps your OS). [Note that testing something where the fit is exact is not a very clever idea: you don't need smoothing splines to fit a cubic. It is entirely possible that a realistic problem would work.] In any case, we cannot debug your machine: you have the source code so please debug it yourself and if a MacOS-specific patch is needed please submit it to the maintainer (who might decline to add workarounds for broken systems).
On Tue, 1 Apr 2003 h95mr@mun.ca wrote:
To whom it may concern, I don't know whether this is really a bug with the Pspline package or only a problem with my installation. Things work fine in Linux but not in Mac OS X (Darwin). Both system run the latest public versions of R and Pspline. predict.smooth.Pspline produces only NaN instead of predicted values when norder>2:
library (Pspline) tt <- seq (0,1,length=20) xt <- tt^3 fit <- smooth.Pspline (tt, xt, norder=3,spar=0.0001, method=1) predict.smooth.Pspline (fit, tt, nderiv=0)[,1]
[1] NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN [20] NaN
smooth.Pspline seems to work fine since
plot (tt,xt) lines (fit)
produces the expected result (curve fits data closely). Using norder = 2 instead works fine:
fit2 <- smooth.Pspline(tt,xt,norder=2,spar=0.0001,method=1) lines(fit2, col="red") px <- predict(fit2,tt)[,1] round(px,2)
[1] 0.00 0.00 0.00 0.00 0.01 0.02 0.03 0.05 0.07 0.11 0.15 0.19 0.25 0.32 0.40 [16] 0.49 0.60 0.72 0.85 0.99
round(xt,2)
[1] 0.00 0.00 0.00 0.00 0.01 0.02 0.03 0.05 0.07 0.11 0.15 0.19 0.25 0.32 0.40 [16] 0.49 0.60 0.72 0.85 1.00
version
_ platform powerpc-apple-darwin6.2 arch powerpc os darwin6.2 system powerpc, darwin6.2 status major 1 minor 6.1 year 2002 month 11 day 01 language R
Brian D. Ripley, ripley@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 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595