Making sense of numbers returned by createIntegral in roofit

Roofit and RooStats
1

I am trying to verify the normalization of my pdf’s and see their fractions in roofit.

My final model consists of three Asymmetric Gaussians:

RooAddPdf dg_mdz1("dg_mdz1","dg_mdz1",RooArgList(asy_gauss1,bigauss,asy_gauss3),RooArgList(frac_asymgauss1,fr2)) ;

RooExtendPdf dg_mdz("dg_mdz","dg_mdz",dg_mdz1,nsig);

When I do the following:

RooAbsReal *idg_mdz = dg_mdz.createIntegral(M_dz);
cout<<"Value of integral is "<<idg_mdz->getVal()<<endl<<endl;

I get a value = 0.0113606. I couldn’t understand how is this number calculated or what information it represents.

I have tried to go through previous roofit posts related to integral but couldn’t get my answer. Any explanation will be really helpful.

2

Hello @amroo,

check this out:
https://root.cern.ch/doc/master/classRooAbsReal.html#a9f63ba99843794d2c9dcbc5b5d20fd47

I guess what you are observing is the stuff mentioned in the section Note?

You can also check the tutorial mentioned there.