PDF Extension

Dear Experts,

I’m trying to minimize my likelihood function, which can be expressed as

and i’m using createNLL():

RooAbsReal* nll = genpdf->createNLL(binnedModel,
RooFit::Extended(true),
RooFit::Offset(true),
RooFit::NumCPU(4));

My question is whether createNLL by default takes into account the N_i! (which is the observed number of events in bin i) term as well or not, because I found that this term can be inserted(Extended-PDF) :

Will enabling RooFit::Extended(true) do this automatically, or does it need to be inserted as described on page 32 of the above document?

The other part of my question is, given that I have 6 parameters to minimize, is there a way to constrain their limits (range) in such a way that all of them show a minimum in the plots of (NLL vs. Parameter)?

PS: The real values of these parameters are known from a given formula, which I have used as starting values in the fit.

Thanks,
Mustapha

Hi @Mustaphaa,
@jonas should be able to help you with your question.

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