[Rd] predict in Pspline package (PR#2714)

[h95mr at mun.ca]

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            



The same code works fine in Linux:

>  rm (list=ls())
>  library(pspline)
>  tt <- seq (0,1,length=20)
>  xt <- tt^3
>  fit <- smooth.Pspline (tt, xt, norder=3,spar=0.0001, method=1)
>  px<-predict(fit,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 1.00
>
>  version
          _
platform i686-pc-linux-gnu
arch     i686
os       linux-gnu
system   i686, linux-gnu
status
major    1
minor    6.1
year     2002
month    11
day      01
language R
>


Please let me know if I can help in any way troubleshooting this 
issue. Kind regards,
	Martin



-- 


Martin Renner                        email: h95mr at mun.ca
Department of Biology                http://www.ucs.mun.ca/~h95mr/
Memorial University of Newfoundland  Office: SN-2093
St. John's, NL, A1B 3X9    	     phone: (709) 737-3239
CANADA                               fax:   (709) 737-3018

What difference does it make to the dead, the orphans, and the 
homeless, whether the mad destruction is brought under the name of 
totalitarianism or the holy name of liberty and democracy?  - Gandhi