Message-ID: <Pine.LNX.4.44.0304010831580.9425-100000@gannet.stats>
Date: 2003-04-01T09:39:24Z
From: Brian Ripley
Subject: predict in Pspline package (PR#2714)
In-Reply-To: <200304010002.h31027n9022168@pubhealth.ku.dk>
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