void test() {
    auto datafile="test_data.txt";
    double calfact = 0.8;
    int nbxbins = 20032;
    double caloffset = 27765996.8;
    auto xlow = caloffset-0.5*calfact;
    auto xup = caloffset+(nbxbins-0.5)*calfact;
    int cycles = 1000;
    double roilow = 27776120.0000;
    auto roimax = 27776510.0000;

    for (int i = 0; i < 4; ++i) {
        TH2D th2("th2","th2",nbxbins, xlow, xup, cycles, 0, cycles);
        th2.SetBinContent(13112,1,1);
        th2.GetXaxis()->SetRangeUser(roilow,roimax);
        auto th1 = th2.ProjectionX("th1");
        RooWorkspace w("w");
        std::stringstream s;
        s << "Gaussian:gauss(t[" << roilow << "," << roimax << "],mean[" << th1->GetMean() << "," << roilow << "," << roimax << "],sigma[" << th1->GetStdDev() << "," << 5 << "," << 120 << "])";
        w.factory(s.str().c_str());
        RooRealVar *t = w.var("t");
        auto mean = w.var("mean");
        auto sigma = w.var("sigma");
        auto pdf = w.pdf("gauss");
        w.defineSet("nuisParams","sigma");
        TObjArray tobj;
        TF1 f1("f1","gaus(0)",roilow,roimax);
        th2.FitSlicesX(&f1,0,-1,0,"QNR",&tobj);
        RooDataHist data("data","data", RooArgList(*t), RooFit::Import(*th1));
        auto res = pdf->fitTo(data,RooFit::Save(true));
        RooStats::ModelConfig mc("ModelConfig", &w);
        mc.SetPdf(*pdf);
        mc.SetParametersOfInterest(RooArgSet(*mean));
        mc.SetObservables(RooArgSet(*t));
        mc.SetNuisanceParameters(*w.set("nuisParams"));
        RooStats::ProfileLikelihoodCalculator plCalc(data,mc);
        plCalc.SetConfidenceLevel(0.68);
        auto pll_interval = plCalc.GetInterval();
        TCanvas c("c","Profile Likelyhood", 200, 10, 700, 500);
        c.cd(1);
        RooStats::LikelihoodIntervalPlot plot(pll_interval);
        plot.Draw("TF1");
    }
}