%%cpp -d
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooChebychev.h"
#include "RooAddPdf.h"
#include "RooMCStudy.h"
#include "RooChi2MCSModule.h"
#include "RooPlot.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "TH1.h"
#include "TDirectory.h"
#include "TLegend.h"

using namespace RooFit;

RooRealVar x("x", "x", -10, 10);
x.setBins(10);
RooRealVar mean("mean", "mean of gaussian", 0, -2., 1.8);
RooRealVar sigma("sigma", "width of gaussian", 5, 1, 10);

RooGaussian gauss("gauss", "gaussian PDF", x, mean, sigma);

RooMCStudy *mcs = new RooMCStudy(gauss, x, Silence(), Binned());

RooChi2MCSModule chi2mod;
mcs->addModule(chi2mod);

mcs->generateAndFit(2000, 1000);

int nBins = 100;

TH1 *hist_chi2 = mcs->fitParDataSet().createHistogram("chi2", AutoBinning(nBins));
hist_chi2->SetTitle("#chi^{2} values of all toy runs;#chi^{2}");
TH1 *hist_prob = mcs->fitParDataSet().createHistogram("prob", AutoBinning(nBins));
hist_prob->SetTitle("Corresponding #chi^{2} probability;Prob(#chi^{2},ndof)");

RooRealVar mean2("mean2", "mean of gaussian 2", 2.);
RooGaussian gauss2("gauss2", "gaussian PDF2", x, mean2, sigma);

RooMCStudy *mcs2 = new RooMCStudy(gauss2, x, FitModel(gauss), Silence(), Binned());

RooChi2MCSModule chi2mod2;
mcs2->addModule(chi2mod2);

mcs2->generateAndFit(2000, 1000);

auto pullMeanFrame = mcs2->plotPull(mean);

TH1 *hist2_chi2 = mcs2->fitParDataSet().createHistogram("chi2", AutoBinning(nBins));
TH1 *hist2_prob = mcs2->fitParDataSet().createHistogram("prob", AutoBinning(nBins));
hist2_chi2->SetLineColor(kRed);
hist2_prob->SetLineColor(kRed);

TLegend leg;
leg.AddEntry(hist_chi2, "Optimal fit", "L");
leg.AddEntry(hist2_chi2, "Biased fit", "L");
leg.SetBorderSize(0);
leg.SetFillStyle(0);

TCanvas *c = new TCanvas("rf802_mcstudy_addons", "rf802_mcstudy_addons", 800, 400);
c->Divide(3);
c->cd(1);
gPad->SetLeftMargin(0.15);
hist_chi2->GetYaxis()->SetTitleOffset(1.4);
hist_chi2->Draw();
hist2_chi2->Draw("esame");
leg.DrawClone();
c->cd(2);
gPad->SetLeftMargin(0.15);
hist_prob->GetYaxis()->SetTitleOffset(1.4);
hist_prob->Draw();
hist2_prob->Draw("esame");
c->cd(3);
pullMeanFrame->Draw();

gDirectory->Add(mcs);

%jsroot on
gROOT->GetListOfCanvases()->Draw()