WilDsc0p wrote:
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


No, but because you are resetting the seed of the random number generator to the same value in each iteration of your loop.





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.


You don't need (see above), but you can with assignInNamespace() and friends, see ?assignInNamespace.


Uwe Ligges




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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