Error in <TTreeReaderValueBase::GetBranchDataType()>: Must use TTreeReaderArray to read branch TrackPara: it contains an array or a collection.
Error in <TTreeReaderArrayBase::CreateProxy()>: The template argument type T of T accessing branch TrackPara (which contains data of type (null)) is not known to ROOT. You will need to create a dictionary for it.
How can I process such branch?
upd.
I guess, that one of solution is just rewrite my ttree and save this branch like RVec, but just for interest - could I avoid it?
As you can see, TTreeReaderArray read only first row of my double array.
How can I fix it?
upd2
How I can understand this is the same problem that described in this ticket for DataFrame: https://sft.its.cern.ch/jira/browse/ROOT-9509
So now we have try to avoid using such arrays.