Index argument with createFolds in traincontrol - caret package I would like to do 10 times repeated 5-fold CV and compare results from more models. Here is one thing I don't understand:
Example of 5-fold CV:

myFolds <- createFolds(loan_data$loan_status, k = 5) 
summary(myFolds)

Lenghts:  
Fold1 -  2011, 
Fold2 -  2012,....., Fold5  - 2012
Folds have ~ 2012 indexes which is ~ 20%
This should make 5 folds and I can use them in  index argument of trainControl function:

myControl <- trainControl(
    method = "cv",
    number = 5,
    summaryFunction = twoClassSummary,
    classProbs = TRUE,
    index = myFolds
  )

From documentation: index
a list with elements for each resampling iteration. Each list element is a vector of integers corresponding to the rows used for training at that iteration.
So does it mean, that train function  will in all 5 resamples train data on ~2011 rows and test on ~8044 rows? Should I use indexOut instead of index if I want 80% train and 20% test? 
Second function : 

myFolds <- createMultiFolds(loan_data$loan_status, 5, 10)
summary(myFolds)

Fold1.Rep1:    8047,.......
Fold5.Rep10:   8048
Folds have ~ 8048 indexes which is ~ 80%
It seems like createMultiFolds creates folds for TRAINING sets while createFolds creates folds for TESTING sets. Am I right?  In this example, question is same... Should I use index or indexOut?   

myControl <- trainControl(method = "repeatedcv",
    number = 5,repeats = 10,
    summaryFunction = twoClassSummary,
    classProbs = TRUE,
    index = myFolds
    #indexOut = myFolds
  )

Thank you for any explanation.
 A: Here is my experience/summary:
if you want to return train set, you can createFolds(loan_data$loan_status, k = 5, returnTrain=TRUE)
internally, createMultiFolds(loan_data$loan_status, 5, 10) calls createFolds(returnTrain=TRUE)
when you use index in trainControl() the parameters number, repeats are ignored (https://github.com/topepo/caret/issues/584)
A: Best case you predefine your indices via createMultiFolds.
Its important that by default - if "cv" selected instead of "repeatedcv" or repeates not defined in trainControl - there won't be repeates.
So, you have to predefine you multifold indices then set the number of repeates in the trainControl.
k - number of the folds will be automatically recognized and used
t - times (repeates) must be defined
multiFoldIndices <- createMultiFolds(y_train,5,3)
caretListRes <- caretList(x_train,
                          y_train,
                          trControl = trainControl(method = "repeatedcv",
                                                   index = multiFoldIndices,
                                                   repeats = 3,
                                                   savePredictions = "final",
                                                   allowParallel = TRUE
                                                   ),
                          methodList = c("lm","rf"),
                          preProcess = c("center","scale")
                          )

