I’m using the PLR procedure with RooStat and RooFit and I have a very concerning issue.
I’m defining a likelihood with external constrains on some nuisance parameter and during the first fit of the PLR, I receive this message:
[#0] WARNING:Eval -- RooAbsPdf::getLogVal(Constraint_Neutrino) WARNING: large likelihood value: 2.5168e+07
I’m defining the external constrain in this way:
RooRealVar N(Form("N_%s", contrib_name), Form("Number of %s bkg events", contrib_name), Ncount, 0, Ncount*10); N.setVal(Ncount); RooRealVar N0(Form("N0_%s", contrib_name),Form("Estimated number of %s bkg events from aux measurement", contrib_name), Ncount); N0.setConstant(1); RooRealVar sigmaN0(Form("sigmaN0_%s", contrib_name), Form("Absolute error on expected %s BG", contrib_name), activitySigma * Ncount); sigmaN0.setConstant(1); fw->import(N0); fw->import(sigmaN0); fw->factory(Form("Gaussian::Constraint_%s(N_%s, N0_%s, sigmaN0_%s)", contrib_name, contrib_name, contrib_name, contrib_name));
The value of
sigmaN0 = 0.2* Ncount
Any idea where this could come from ?