R 使用插入符号消除递归特征时出错

我试图使用插入符号进行变量选择，但在某些类型的模型中，我在同一点上遇到了一个错误。我在下面重现了一个错误：{：任务1失败中的错误-下标超出范围”，但我还使用其他数据获取了“任务1失败中的错误-{：任务1失败-”替换有XXX行，数据有YYY“”

我对解决这个特殊的错误感兴趣，并对如何调试这个问题提出建议。谢谢

library(caret)
data(iris)

predictors <- names(iris)[names(iris)!="Species"]

split <- createDataPartition(iris$Species, p = .8, list = FALSE)
irisData <- iris[,predictors]
irisData$Class <- iris$Species

training <- irisData[ split, ]
testing  <- irisData[-split, ]

times <- 1
folds <- 5
prednumSeq <- seq(1, length(predictors)-1, by = 1)

ctrl <- rfeControl(method = "repeatedcv", 
                  timingSamps = 2,
            number = folds,
            repeats = times,
            saveDetails = TRUE,
                  verbose = TRUE,
            allowParallel = FALSE)

rfRFE <- rfe(training[,predictors],
                training$Class,
                sizes = prednumSeq,
                rfeControl = ctrl) 

sessionInfo（）中的详细信息包括：

尝试

options（error=recover）

并查看是否可以发现有问题的行。

+(rfe) fit Fold1.Rep1 size: 4 
-(rfe) fit Fold1.Rep1 size: 4 
+(rfe) imp Fold1.Rep1 
+(rfe) fit Fold2.Rep1 size: 4 
-(rfe) fit Fold2.Rep1 size: 4 
+(rfe) imp Fold2.Rep1 
+(rfe) fit Fold3.Rep1 size: 4 
-(rfe) fit Fold3.Rep1 size: 4 
+(rfe) imp Fold3.Rep1 
+(rfe) fit Fold4.Rep1 size: 4 
-(rfe) fit Fold4.Rep1 size: 4 
+(rfe) imp Fold4.Rep1 
+(rfe) fit Fold5.Rep1 size: 4 
-(rfe) fit Fold5.Rep1 size: 4 
+(rfe) imp Fold5.Rep1 
Error in { : task 1 failed - "subscript out of bounds"

R version 3.0.0 (2013-04-03)
Platform: x86_64-w64-mingw32/x64 (64-bit)

locale:
[1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252 LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

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

other attached packages:
 [1] MASS_7.3-26        randomForest_4.6-7 e1071_1.6-1        class_7.3-7       
 [5] pROC_1.5.4         caret_5.15-61      reshape2_1.2.2     plyr_1.8          
 [9] lattice_0.20-15    foreach_1.4.0      cluster_1.14.4    

loaded via a namespace (and not attached):
[1] codetools_0.2-8 compiler_3.0.0  grid_3.0.0      iterators_1.0.6 stringr_0.6.2  
[6] tools_3.0.0