[R] Overlapping parameters "k" in different functions in "ipred"

WilDsc0p wildscop at yahoo.com
Sat Apr 25 08:44:29 CEST 2009


Dear List,

I have a question regarding "ipred" package. Under 10-fold cv, for different knn ( = 1,3,...25), I am getting same misclassification errors:
#############################################
library(ipred) 
data(iris) 
cv.k = 10 ## 10-fold cross-validation 
bwpredict.knn <- function(object, newdata) predict.ipredknn(object, newdata, type="class") 
for (i in seq(1,25,2)){
set.seed(19)
a<-errorest(Species ~ ., data=iris, model=ipredknn, estimator="cv", est.para=control.errorest(k=cv.k), predict=bwpredict.knn, nk = i)$err 
print(a)
}
[1] 0.02666667
[1] 0.02666667
[1] 0.02666667
[1] 0.02666667
[1] 0.02666667
[1] 0.02666667
[1] 0.02666667
[1] 0.02666667
[1] 0.02666667
[1] 0.02666667
[1] 0.02666667
[1] 0.02666667
[1] 0.02666667
#############################################
I think its is because in "ipredknn" and "control.errorest" has the same variable "k" (I guess k=5 default in ipredknn is returning). If I use

errorest(Species ~ ., data=iris, model=ipredknn, estimator="cv", est.para=control.errorest(k=cv.k), predict=bwpredict.knn, k = 1)

the following message is generated:
Error in cv.factor(y, formula, data, model = model, predict = predict,  : 
  formal argument "k" matched by multiple actual arguments

I can't seem to change "k" to "nk" in "ipredknn". If I try
ipred::ipredknn <- function (formula, data, subset, na.action, nk = 5, ...){.......}
I get the message-
Error in ipred::ipredknn <- function(formula, data, subset, na.action,  : 
  object "ipred" not found

How can I fix that? Any suggestion would be greatly appreciated.

Thanks in advance,


- mek

R.Version() $platform "i386-pc-mingw32" $arch "i386" $os "mingw32" $system "i386, mingw32" $status "" $major "2" $minor "8.1" $year "2008" $month "12" $day "22" $`svn rev` "47281" $language "R" $version.string "R version 2.8.1 (2008-12-22)"




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