More information is needed to be sure, but it is most likely that some of the resampled rpart models produce the same prediction for the hold-out samples (likely the result of no viable split being found).
Almost every incarnation of R^2 requires the variance of the prediction. This particular failure mode would result in a divide by zero. Try using you own summary function (see ?trainControl) and put a print(summary(data$pred)) in there to verify my claim. Max On Wed, May 16, 2012 at 11:30 AM, Max Kuhn <mxk...@gmail.com> wrote: > More information is needed to be sure, but it is most likely that some > of the resampled rpart models produce the same prediction for the > hold-out samples (likely the result of no viable split being found). > > Almost every incarnation of R^2 requires the variance of the > prediction. This particular failure mode would result in a divide by > zero. > > Try using you own summary function (see ?trainControl) and put a > print(summary(data$pred)) in there to verify my claim. > > Max > > On Tue, May 15, 2012 at 5:55 AM, Dominik Bruhn <domi...@dbruhn.de> wrote: >> Hy, >> I got the following problem when trying to build a rpart model and using >> everything but LOOCV. Originally, I wanted to used k-fold partitioning, >> but every partitioning except LOOCV throws the following warning: >> >> ---- >> Warning message: In nominalTrainWorkflow(dat = trainData, info = >> trainInfo, method = method, : There were missing values in resampled >> performance measures. >> ----- >> >> Below are some simplified testcases which repoduce the warning on my >> system. >> >> Question: What does this error mean? How can I avoid it? >> >> System-Information: >> ----- >>> sessionInfo() >> R version 2.15.0 (2012-03-30) >> Platform: x86_64-pc-linux-gnu (64-bit) >> >> locale: >> [1] LC_CTYPE=en_GB.UTF-8 LC_NUMERIC=C >> [3] LC_TIME=en_GB.UTF-8 LC_COLLATE=en_GB.UTF-8 >> [5] LC_MONETARY=en_GB.UTF-8 LC_MESSAGES=en_GB.UTF-8 >> [7] LC_PAPER=C LC_NAME=C >> [9] LC_ADDRESS=C LC_TELEPHONE=C >> [11] LC_MEASUREMENT=en_GB.UTF-8 LC_IDENTIFICATION=C >> >> attached base packages: >> [1] stats graphics grDevices utils datasets methods base >> >> other attached packages: >> [1] rpart_3.1-52 caret_5.15-023 foreach_1.4.0 cluster_1.14.2 >> reshape_0.8.4 >> [6] plyr_1.7.1 lattice_0.20-6 >> >> loaded via a namespace (and not attached): >> [1] codetools_0.2-8 compiler_2.15.0 grid_2.15.0 iterators_1.0.6 >> [5] tools_2.15.0 >> ------- >> >> >> Simlified Testcase I: Throws warning >> --- >> library(caret) >> data(trees) >> formula=Volume~Girth+Height >> train(formula, data=trees, method='rpart') >> --- >> >> Simlified Testcase II: Every other CV-method also throws the warning, >> for example using 'cv': >> --- >> library(caret) >> data(trees) >> formula=Volume~Girth+Height >> tc=trainControl(method='cv') >> train(formula, data=trees, method='rpart', trControl=tc) >> --- >> >> Simlified Testcase III: The only CV-method which is working is 'LOOCV': >> --- >> library(caret) >> data(trees) >> formula=Volume~Girth+Height >> tc=trainControl(method='LOOCV') >> train(formula, data=trees, method='rpart', trControl=tc) >> --- >> >> >> Thanks! >> -- >> Dominik Bruhn >> mailto: domi...@dbruhn.de >> >> >> >> >> ______________________________________________ >> R-help@r-project.org mailing list >> 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. >> > > > > -- > > Max -- Max ______________________________________________ R-help@r-project.org mailing list 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.