aVirtualTwins is written mainly with reference classes. Briefly, there is three kinds of class :
VT.object class to represent RCT dataset used by aVirtualTwins. To format correctly RCT dataset, use formatRCTDataset.
VT.difft class to compute difference between twins. Family VT.forest extends it to compute twins by random forest.
vt.forest is users function.
VT.tree class to find subgroups from difft by CART trees. VT.tree.class and VT.tree.reg extend it. 
vt.tree is users function.
See http://github.com/prise6/aVirtualTwins for last updates.
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