how the folds in cross validation of libSVM are done?, I mean, the splits are done aleatory? for example if I have 100 data and it is 4-fold then when it is an aleatory folding then can be splited like this?
- 20-45 : fold1
- 45-70 : fold2
- 70-95 : fold3
- 95-20 : fold4
or it make the folds always starting from the first one:
- 1-25 : fold1
- 25-50 : fold2
- 50-75 : fold3
- 75-100 : fold4
so how can I choose which kind on folding I want to use?
Thank you for your answers
Best Answer
I think you misunderstand the way folds are generated in cross-validation. In cross-validation, your data set is partitioned at random into a specific number of folds.* The data is not partitioned as you would slice a pie (e.g. adjacent instances belonging to the same fold).
*: in stratified cross-validation the class balance in the overall data set is maintained across folds.