#include <iostream>
void cluster_data(){
using namespace RooFit;
TCanvas *c1 = new TCanvas("c1","Dynamic Filling Example",200,10,700,500);
TCanvas *c2 = new TCanvas("c2","Dynamic Filling Example",200,10,700,500);

RooRealVar zd_1("zd_1","zd_1",10,62.5,"GeV");
RooRealVar zd_2("zd_2","zd_1",10,62.5,"GeV");

RooRealVar mean_zd_1("mean_zd_1","mean of zd_1",20.12);
RooRealVar mean_zd_2("mean_zd_2","mean of zd_2",27.36);

RooRealVar sigma_zd_1("sigma_zd_1","width of zd_1",4.70);
RooRealVar sigma_zd_2("sigma_zd_2","width of zd_2",5.83);

RooGaussian gaus_zd_1("gaus_zd_1","gaus_zd_1",zd_1,mean_zd_1,sigma_zd_1);
RooGaussian gaus_zd_2("gaus_zd_2","gaus_zd_2",zd_2,mean_zd_2,sigma_zd_2);

RooProdPdf prod("gaus_zd_12","gaus_zd_1*gaus_zd_2",RooArgList(gaus_zd_1,gaus_zd_2));
RooDataSet *data = prod.generate(RooArgList(zd_1,zd_2),1000);
////
//TH2 * zd1zd2 = new zd_1.createHistogram("zd1 vs zd2",zd_2,0,0,0,bins);
//prod.fillHistogram(zd1zd2,RooArgList(zd_1,zd_2));
// data->numEntries();


    RooPlot *xframe = zd_1.frame("s");
    data->plotOn(xframe);
    prod.plotOn(xframe);
//xframe->Draw();

    RooPlot *yframe = zd_2.frame();
    data->plotOn(yframe);
    prod.plotOn(yframe);
    data->reduce("zd_2/zd_1>1");
    c1->cd();
    xframe->Draw();
    c2->cd();
    yframe->Draw();


    data->print();
    //    c2->update();
//    TH2* ph2 = x.createHistogram("x vs y pdf",y,0,0,0,bins);
//    prod.fillHistogram(ph2,RooArgList(x,y));
//    ph2->Draw("SURF");
//RooDataSet* data1 = data.reduce("gaus_zd_2>2");
}