[R] e1071 question: what's the definition of performance in t une.* functions?
thchung at tgen.org
Tue Jul 13 18:46:20 CEST 2004
Thank you Andy.
It seems like this can be the reason for the confusion.
I never thought that there can be this kind of catches for using tune.*
For the record, I actually emailed to Dr. Friedrich Leisch the author
of this library.
When I get some reply, I will post it also.
On Jul 12, 2004, at 6:40 PM, Liaw, Andy wrote:
> Looking at the body of tune(), it has:
> repeat.errors[reps] <- if (is.factor(true.y))
> 1 - classAgreement(table(pred, true.y))
> else crossprod(pred - true.y)/length(pred)
> where classAgreement() is a function defined inside tune() that
> computes the
> fraction of correctly predicted cases. So it looks like tune() and
> are returning error rates as fractions, not percentages.
> You're right that the fraction shouldn't be larger than 1. Did you
> sure that tune() sees the data as classification, not regression
> (i.e., did
> you make sure that the class labels given to tune.*() are factor)?
Tae-Hoon Chung, Ph.D
Post-doctoral Research Fellow
Molecular Diagnostics and Target Validation Division
Translational Genomics Research Institute
1275 W Washington St, Tempe AZ 85281 USA
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