Is BuildIndex() still necessary on TChain when included trees already have indices?

[LeWhoo]

Quite an old one

TChain/TTree Polymorphishm & BuildIndex / GetEntryWithIndex

Hi, If you build an index for the whole chain it should work fine. Alternatively, you can build the index for each individual TTree but then you need to also make sure it is stored in the file. Cheers, Philippe.