Monte Carlo event weights in BDT

TMVA
1

Hello!

I’m training a BDT and a DNN with real data and some Monte Carlo simulated data. As real data has weight equal to 1, and simulated data has weights bigger or smaller than 1, I was wondering how could I include this weights into the model trainings. For BDT I could take them in as weights for the trees, or as initial weights for each event? And for DNN, could the weights be incorporated as initial weights too?

I would really appreciate your guidance.

Thank you in advance.
Have a nice weekend!

2

Hi

TMVA provides support for both DNN and BDT of single event weights. You need just to call the function DataLoader::SetSignalWeightExpression for the signal tree and DataLoader::SetBackgroundWeightExpression for the background tree. You can see example in the tutorial, ``TMVAClassification.C`
https://root.cern.ch/doc/master/TMVAClassification_8C.html

Lorenzo

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1 Like
3

Thanks for the answer.

So if I understand well, dataloader->SetBackgroundWeightExpression( "weight" ) takes the variable “weight” from the signal tree?

I really apprecciate your help.

Kind regards.

4

Indeed, it is so.

Cheers,
Kim