rf403_weightedevts_modified.C

/// \file
/// \ingroup tutorial_roofit
/// \notebook -js
///  'DATA AND CATEGORIES' RooFit tutorial macro #403
///
///  Using weights in unbinned datasets
///
/// \macro_image
/// \macro_output
/// \macro_code
/// \author 07/2008 - Wouter Verkerke


#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooDataHist.h"
#include "RooGaussian.h"
#include "RooConstVar.h"
#include "RooFormulaVar.h"
#include "RooGenericPdf.h"
#include "RooPolynomial.h"
#include "RooChi2Var.h"
#include "RooMinimizer.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "RooPlot.h"
#include "RooFitResult.h"
using namespace RooFit ;


void rf403_weightedevts()
{
   // C r e a t e   o b s e r v a b l e   a n d   u n w e i g h t e d   d a t a s e t
   // -------------------------------------------------------------------------------

   // Declare observable
   RooRealVar x("x","x",-10,10) ;
   x.setBins(40) ;
   x.setRange("LEFT",-10,-6);
   x.setRange("RIGHT",6,10);

   // Construction quadratic polynomial pdf for fitting
   RooRealVar a0("a0","a0",1) ;
   RooRealVar a1("a1","a1",0,-1,1) ;
   RooRealVar a2("a2","a2",1,0,10) ;
   RooPolynomial p1("p1","p1",x,RooArgList(a0,a1,a2),0) ;

   RooRealVar b0("b0","b0",1) ;
   RooRealVar b1("b1","b1",0,-1,1) ;
   RooRealVar b2("b2","b2",1,0,10) ;
   RooPolynomial p2("p2","p2",x,RooArgList(b0,b1,b2),0) ;

   RooRealVar c0("c0","c0",1) ;
   RooRealVar c1("c1","c1",0,-1,1) ;
   RooRealVar c2("c2","c2",1,0,10) ;
   RooPolynomial p3("p3","p3",x,RooArgList(c0,c1,c2),0) ;

   // Sample 1000 events from pdf
   RooDataHist* data = p1.generateBinned(x,1000) ;

   // Construct plot frame
   RooPlot* frame1 = x.frame(Title("RooChi2Var(Range(\"LEFT,RIGHT\") and RooMinimizer()")) ;
   RooPlot* frame2 = x.frame(Title("chi2FitTo(Range(\"LEFT,RIGHT\")")) ;
   RooPlot* frame3 = x.frame(Title("fitTo(Range(\"LEFT,RIGHT\")")) ;

   // Fit and plot first frame
   RooChi2Var chi2("chi2","chi2",p1,*data,Range("LEFT,RIGHT")) ;
   RooMinimizer m(chi2) ;
   m.migrad() ;
   m.hesse() ;
   data->plotOn(frame1) ;
   p1.plotOn(frame1,LineStyle(kDashed),LineColor(kRed), NormRange("LEFT,RIGHT")) ;

   // Fit and plot second frame
   p2.chi2FitTo(*data, Range("LEFT,RIGHT"));
   data->plotOn(frame2) ;
   p2.plotOn(frame2,LineStyle(kDashed),LineColor(kRed), NormRange("LEFT,RIGHT")) ;

   // Fit and plot third frame
   p3.fitTo(*data, Range("LEFT,RIGHT"));
   data->plotOn(frame3) ;
   p3.plotOn(frame3,LineStyle(kDashed),LineColor(kRed), NormRange("LEFT,RIGHT")) ;

   // Draw
   TCanvas* c = new TCanvas("rf403_weightedevts","rf403_weightedevts",1200,400) ;
   c->Divide(3);
   c->cd(1);
   frame1->Draw() ;
   c->cd(2);
   frame2->Draw() ;
   c->cd(3);
   frame3->Draw() ;
}