RooSimultaneous with different x range

[choccy]

Dear experts,

I am trying to use RooSimultaneous to fit with different datasets in different ranges, and this fit has a correlated variable that I need to get from the simultaneous result. I am not sure if this is allowed in the roosimultaneous, and if the same x variable will have correlation?

the code is like:

RooDataSet data1("data1", "data1", Tree1, RooArgSet(x));
RooDataSet data2("data2", "data2", Tree2, RooArgSet(x));

RooCategory sample("sample", "sample");
sample.defineType("1data");
sample.defineType("2data");
        
x.setRange("fitRange_1data", xmin1, xmax1);
x.setRange("fitRange_2data", xmin2, xmax2);

RooDataSet comdata("comdata", "combine data", x, Index(sample), Import("1data",data1), Import("2data",data2));

RooSimultaneous simPdf("simPdf", "simultaneous fit", sample);
      
simPdf.addPdf(pdf1,"1data");
simPdf.addPdf(pdf2,"2data");
RooFitResult  fitres = (RooFitResult*)simPdf->fitTo(comdata,Range("fitRange"), SplitRange(), Extended(true), Minos(false),Save(true));
type or paste code here

here data1 & data2 has to fit with the same x variable but in different range, however they are not correlated in x variable, but in another variable (let’s say it ratio). The fits looks quite weird, and I am not sure if the two dataset have correlation in x variable, do you have any suggestions?

Cheers,
Yanting

[eguiraud]

Hi @choccy ,
sorry for the late reply!

Let’s ping our RooFit expert @moneta .

Cheers,
Enrico

[moneta]

Hi,
You would need to post in addition to your full running code also your data set, so we can understand what the problem is.

Cheers

Lorenzo