Compare many tress with the same name in different files

ROOT
1

Hi,
I have many files in which I have a tree with the same name and with the same number of rows, but coming from different elaborations.
For example,
in file 1 I have a tree with name EVT elaborated with the algorithm A with N events
in file 2 I have a tree with name EVT elaborated with the algorithm B with N events
in file 3 I have a tree with name EVT elaborated with the algorithm C with N events
and so on

I have tried with AddFriend, but I’m not able to display the data of one or another tree, even if in the TreeViewer the different tree are shown.

How is possibile to work with this configuration. For example, I would like to do the following command

EVT->Draw(“EVT1.COL1:EVT2.COL1”)

where EVT1 and EVT2 are the EVT trees coming from file1 and file2.

Thanks!
Best regards
Andrea Bulgarelli

2

AddFriend is the correct idea. To disambiguate the names you also need to set an alias (at the time of the call to AddFriend). aka tree.AddFriend("EVT2 = EVT","friendfile1.root"); EVT->Draw("EVT.COL1:EVT2.COL1");

Cheers,
Philippe