Using TPySelector for PROOF-Lite analysis


I send a post in PROOF support last week but i think PROOF is not my problem, it’s TPySelector. I’ve created a TPySelector class, called, to analyze a TTree file, “mytree.root”. At the moment, to make it easy and focus the problem, I only analyze one of the branches. I want to do this using PROOF (since a main file,, attached below) but It doesn’t work, it displays an error “Events skipped”. If i run the same analysis (I think it is the same) in C++ or without chain.setProof() line, it gives me the correct output.

Thanks and cheers!

Aida (675 Bytes) (1.72 KB)


Does it work properly with the Python selector without PROOT?
Can you provide the root file so that we can reproduce the problem?


I attach the root file with only 1000 events. Thanks for your help!

mytree1000.root (130 KB)

Script unrunnable: load external modules, etc. Can not know problem is problem with script, setup, …

Guess: not have PYTHONPATH envar point location.
Guess also: Selec_good data members only set on Begin() and is not called on slave. Better init or both Begin/SlaveBegin set all envar.

Check PROOF logs. Python errors there.


My problem is fixed! I hadn’t copied the module to the PYTHONPATH location. And yes, i have to create the histograms and other members in the SlaveBegin function.

Thank you so much and great work :wink: