void test(){
  using namespace RooFit;

  RooRealVar x("x", "y", -10, 10);
  x.setBins(10);
  RooRealVar y("y", "y", 0, 100);
  y.setBins(20);

  //Signal region and backgound region
  RooCategory cat("cat", "cat");
  cat.defineType("SR", 0);
  cat.defineType("BR", 1);

  //2D setup for signal
  RooRealVar meanS("meanS", "meanS", 0);
  RooRealVar widthS("widthS", "widthS", 3);
  RooGaussian gS("gS", "gS", x, meanS, widthS);
  RooRealVar tauS("tauS", "tauS", -0.10);
  RooExponential eS("eS", "eS", y, tauS);
  RooProdPdf modelS("modelS", "modelS", gS, eS);
  // 2D setup for background
  RooRealVar meanB("meanB", "meanB", -1);
  RooRealVar widthB("widthB", "widthB", 5);
  RooGaussian gB("gB", "gB", x, meanB, widthB);
  RooRealVar tauB("tauB", "tauV", -0.30);
  RooExponential eB("eB", "eB", y, tauB);
  RooProdPdf modelB("modelB", "modelB", gB, eB);
  //Signal region is mostly Signal and backgeound region is mostly background
  //models for signal and background
  RooRealVar s("s", "s", 100000);
  RooRealVar b("b", "b", 100000);
  RooRealVar eff_s("eff_s", "eff_s", 0.8);  
  RooRealVar eff_b("eff_b", "eff_b", 0.1); 

  // number of events in the signal region is s*eff_s +b*eff_b
  RooFormulaVar sSR("sSR", "s*eff_s", RooArgList(s, eff_s)); 
  RooFormulaVar sBR("sBR", "s*(1-eff_s)", RooArgList(s, eff_s)); 
  // number of events in the background region is s*(1-eff_s) +b*(1-eff_b)
  RooFormulaVar bSR("bSR", "b*eff_b", RooArgList(b, eff_b));
  RooFormulaVar bBR("bBR", "b*(1-eff_b)", RooArgList(b, eff_b));
  //models for SR and BR
  RooAddPdf modelSR("modelSR", "modelSR", RooArgList(modelS, modelB), RooArgList(sSR, bSR));
  RooAddPdf modelBR("modelBR", "modelBR", RooArgList(modelS, modelB), RooArgList(sBR, bBR)); 

  RooSimultaneous modelTotal("modelTotal", "modelTotal", cat);
  modelTotal.addPdf(modelSR, "SR");
  modelTotal.addPdf(modelBR, "BR");

  //generate the individual components to check the normalizations when plotting
  cat.setLabel("SR");
  RooDataSet* dataS_SR = modelS.generate(RooArgSet(cat, x, y), sSR.getValV());
  cat.setLabel("BR");
  RooDataSet* dataS_BR = modelS.generate(RooArgSet(cat, x, y), sBR.getValV());

  cat.setLabel("SR");
  RooDataSet* dataB_SR = modelB.generate(RooArgSet(cat, x, y), bSR.getValV());
  cat.setLabel("BR");
  RooDataSet* dataB_BR = modelB.generate(RooArgSet(cat, x, y), bBR.getValV());

  RooDataSet* data = (RooDataSet*) dataS_SR->Clone();
  data->append(*dataS_BR);
  data->append(*dataB_SR);
  data->append(*dataB_BR);

  RooPlot* frameX_SR = x.frame();
  data->plotOn(frameX_SR, Cut("cat==cat::SR"));
  dataS_SR->plotOn(frameX_SR, MarkerColor(kRed), LineWidth(0));
  modelTotal->plotOn(frameX_SR, Slice(cat, "SR"), ProjWData(*data), Components(modelS), LineColor(kRed));
  
  
  RooPlot* frameX_BR = x.frame();
  data->plotOn(frameX_BR, Cut("cat==cat::BR"));

  RooPlot* frameY_SR = y.frame();
  RooPlot* frameY_BR = y.frame();
  data->plotOn(frameY_SR, Cut("cat==cat::SR"));
  data->plotOn(frameY_BR, Cut("cat==cat::BR"));

  TCanvas * c = new TCanvas();
  c->Divide(2,2);
  c->cd(1);
  frameX_SR->Draw();
  c->cd(2);
  frameX_BR->Draw();
  c->cd(3);
  frameY_SR->Draw();
  c->cd(4);
  frameY_BR->Draw();  


}