%%cpp -d
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooPolyVar.h"
#include "RooProdPdf.h"
#include "RooPlot.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "TH1.h"
using namespace RooFit;

RooRealVar x("x", "x", -5, 5);
RooRealVar y("y", "y", -5, 5);

RooRealVar a0("a0", "a0", -0.5, -5, 5);
RooRealVar a1("a1", "a1", -0.5, -1, 1);
RooPolyVar fy("fy", "fy", y, RooArgSet(a0, a1));

RooRealVar sigmax("sigma", "width of gaussian", 0.5);
RooGaussian gaussx("gaussx", "Gaussian in x with shifting mean in y", x, fy, sigmax);

RooGaussian gaussy("gaussy", "Gaussian in y", y, 0.0, 3.0);

RooProdPdf model("model", "gaussx(x|y)*gaussy(y)", gaussy, Conditional(gaussx, x));

std::unique_ptr<RooDataSet> data{model.generate({x, y}, 10000)};

RooPlot *xframe = x.frame();
data->plotOn(xframe);
model.plotOn(xframe);

RooPlot *yframe = y.frame();
data->plotOn(yframe);
model.plotOn(yframe);

TH1 *hh_model = model.createHistogram("hh_model", x, Binning(50), YVar(y, Binning(50)));
hh_model->SetLineColor(kBlue);

TCanvas *c = new TCanvas("rf305_condcorrprod", "rf05_condcorrprod", 1200, 400);
c->Divide(3);
c->cd(1);
gPad->SetLeftMargin(0.15);
xframe->GetYaxis()->SetTitleOffset(1.6);
xframe->Draw();
c->cd(2);
gPad->SetLeftMargin(0.15);
yframe->GetYaxis()->SetTitleOffset(1.6);
yframe->Draw();
c->cd(3);
gPad->SetLeftMargin(0.20);
hh_model->GetZaxis()->SetTitleOffset(2.5);
hh_model->Draw("surf");

gROOT->GetListOfCanvases()->Draw()