When I try running TMVAClassification.py given in TMVA package I get the following output:
Traceback (most recent call last):
File "TMVAClassification.py", line 424, in <module>
main()
File "TMVAClassification.py", line 153, in main
factory.AddVariable( "myvar1 := var1+var2", 'F' )
AttributeError: 'Factory' object has no attribute 'AddVariable'
In recent ROOT versions (6.06 or 6.08, don’t remember exactly), the TMVA interface has changed. You need to create a TMVA::DataLoader and call AddVariable on the dataloader object.
Just a bit of user feedback: Completely changing the interface in such a disruptive way creates a lot of work downstream. We have code that has to live in ROOT 6.06 and (with new data) in 6.08. In 6.06 there is not even yet a DataLoader class (afaict). The 6.08 release note (“New DataLoader class that allows flexibility in variable and dataset selection.”) does not indicate that this change is embedded in a complete change in interface for TMVA::Factory.
Per the topic Python is used; if so, you can patch up the class in one place to allow for compatibility (and print Python warnings to catch all cases over a period of time).