Signal efficiency in TMVA

TMVA
1

Hello,

How can I change the signal efficiency for the Cut method in the TMVA package?
It seems the default one is 0.7, but I would like to increase it.

Thanks,
Luciano

2

Hello Luciano,

well, you are probably talking about the “reader”… In the call to caclualte the
MVA-output, you can give as second argument the efficiency:

reader->EvaluateMVA( “Cuts method”, effS )

 where effS is the desired efficiency for which you want the cuts. I'm just a little bit surpised, as in the code it is actually defaulted to "0" not 0.7.  The 0.7 is only set explicitly in

the TMVApplication example.

Please let me know if that fixed your problem.

                    Cheers,

                          Helge
3

Hi Luciano,

I assume you mean during the application phase (using the Reader) ?
After booking MethodCuts via:

reader->BookMVA( “Cuts classifier”, " " );

Once you are in the event loop you can retrieve the cuts response for any desired signal efficiency with the command:

Double_t desiredSigEff = 0.6;
Bool_t passed = reader->EvaluateMVA( “Cuts classifier”, desiredSigEff );

TMVA will then choose the appropriate cuts found during the preceding training.

Hope this helps.

Cheers,
Andreas