2 tree classes in one job

ROOT
1

Hi

I have my analysis code that inherits from the event tree class generated with MakeSelector. Now I have a second tree in the same file with different number of entries but with some configuration info that I need to read (i.e. fill a std::map in the SlaveBegin) before executing the event loop on the event tree. Since the number of entries between both trees is different AddFriend did not work. Ideally, I would like to use the methods generated by MakeSelector, e.g. Process(Long64_t entry). Is there an example somewhere for this use case? I wasn’t able to find anything.

thanks
Ignacio

2

Hi,

You need to read and process the second tree when a new file is open.
ROOT/PROOF call the Init method of the steering selector (in this case the one corresponding to the first TTree) when a new file is open, passing as argument a pointer to the TTree object (tree). The TFile object of the open file is available via

tree->GetCurrentFile()

With this you can read any other object in the file and do what you need to do.

Gerri Ganis