[R] get the value of a biplane

[Rui Barradas]

Hello,

Can anyone explain why this error?

 > library(splines)
 >
 > knots <- c(6, 12, 22, 30, 35)
 > x <- c(0.0, .25, 1.0, 2.0, 3.0)
 > SCurve <- bs(x = x, knots = knots, intercept = FALSE, Boundary.knots 
= c(0,3.5))
 > class(SCurve)
[1] "bs"     "basis"  "matrix"
 >
 > ?predict.bs
 > predict.bs(SCurve, xnew = 40:45)
Error in predict.bs(SCurve, xnew = 40:45) :
   could not find function "predict.bs"

Note that splines:::predict.bs(SCurve, xnew = 40:45) works.

 > sessionInfo()
R version 3.4.0 (2017-04-21)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 7 x64 (build 7601) Service Pack 1

Matrix products: default

locale:
[1] LC_COLLATE=Portuguese_Portugal.1252 
LC_CTYPE=Portuguese_Portugal.1252
[3] LC_MONETARY=Portuguese_Portugal.1252 LC_NUMERIC=C 

[5] LC_TIME=Portuguese_Portugal.1252

attached base packages:
[1] splines   stats     graphics  grDevices utils     datasets  methods
[8] base

loaded via a namespace (and not attached):
[1] compiler_3.4.0 tools_3.4.0


Rui Barradas


Em 28-05-2017 17:37, Rui Barradas escreveu:
> Hello,
>
> Since function splines::bs returns an object of class bs in order to
> read the help page for function predict you need
>
> ?predict.bs
>
> The syntax would be
>
> ## S3 method for class 'bs'
> predict(object, newx, ...)
>
> Please read that help page and maybe you'll get the answer you need.
>
> Hope this helps,
>
> Rui Barradas
>
> Em 28-05-2017 15:51, Glenn Schultz escreveu:
>> If is specify a spline basis as follows
>>
>> knots <- c(6, 12, 22, 30, 35)
>> x <- c(0.0, .25, 1.0, 2.0, 3.0)
>> SCurve <- bs(x = x, knots = knots, intercept = FALSE, Boundary.knots =
>> c(0,3.5))
>>
>> I would like to now get the spline value for new values of x.  However,
>> when I use predict the new basis is returned and I would like to get the
>> value.  Nothing has worked so far and ?predict plus examples only show
>> prediction from linear models.  Is there a way to extract the value from
>> a defined spline?
>>
>> Best Regards,
>> Glenn
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.