doc/v606/rf605__profilell_8C.html

#ifndef __CINT__

#include "RooGlobalFunc.h"

#endif

#include "RooRealVar.h"

#include "RooDataSet.h"

#include "RooGaussian.h"

#include "RooConstVar.h"

#include "RooAddPdf.h"

#include "RooMinuit.h"

#include "TCanvas.h"

#include "TAxis.h"

#include "RooPlot.h"

using namespace RooFit ;


void rf605_profilell()

{

  // C r e a t e   m o d e l   a n d   d a t a s e t

  // -----------------------------------------------


  // Observable

  RooRealVar x("x","x",-20,20) ;


  // Model (intentional strong correlations)

  RooRealVar mean("mean","mean of g1 and g2",0,-10,10) ;

  RooRealVar sigma_g1("sigma_g1","width of g1",3) ;

  RooGaussian g1("g1","g1",x,mean,sigma_g1) ;


  RooRealVar sigma_g2("sigma_g2","width of g2",4,3.0,6.0) ;

  RooGaussian g2("g2","g2",x,mean,sigma_g2) ;


  RooRealVar frac("frac","frac",0.5,0.0,1.0) ;

  RooAddPdf model("model","model",RooArgList(g1,g2),frac) ;


  // Generate 1000 events

  RooDataSet* data = model.generate(x,1000) ;


  // C o n s t r u c t   p l a i n   l i k e l i h o o d

  // ---------------------------------------------------


  // Construct unbinned likelihood

  RooAbsReal* nll = model.createNLL(*data,NumCPU(2)) ;


  // Minimize likelihood w.r.t all parameters before making plots

  RooMinuit(*nll).migrad() ;


  // Plot likelihood scan frac

  RooPlot* frame1 = frac.frame(Bins(10),Range(0.01,0.95),Title("LL and profileLL in frac")) ;

  nll->plotOn(frame1,ShiftToZero()) ;


  // Plot likelihood scan in sigma_g2

  RooPlot* frame2 = sigma_g2.frame(Bins(10),Range(3.3,5.0),Title("LL and profileLL in sigma_g2")) ;

  nll->plotOn(frame2,ShiftToZero()) ;


  // C o n s t r u c t   p r o f i l e   l i k e l i h o o d   i n   f r a c

  // -----------------------------------------------------------------------


  // The profile likelihood estimator on nll for frac will minimize nll w.r.t

  // all floating parameters except frac for each evaluation


  RooAbsReal* pll_frac = nll->createProfile(frac) ;


  // Plot the profile likelihood in frac

  pll_frac->plotOn(frame1,LineColor(kRed)) ;


  // Adjust frame maximum for visual clarity

  frame1->SetMinimum(0) ;

  frame1->SetMaximum(3) ;


  // C o n s t r u c t   p r o f i l e   l i k e l i h o o d   i n   s i g m a _ g 2

  // -------------------------------------------------------------------------------


  // The profile likelihood estimator on nll for sigma_g2 will minimize nll

  // w.r.t all floating parameters except sigma_g2 for each evaluation

  RooAbsReal* pll_sigmag2 = nll->createProfile(sigma_g2) ;


  // Plot the profile likelihood in sigma_g2

  pll_sigmag2->plotOn(frame2,LineColor(kRed)) ;


  // Adjust frame maximum for visual clarity

  frame2->SetMinimum(0) ;

  frame2->SetMaximum(3) ;


  // Make canvas and draw RooPlots

  TCanvas *c = new TCanvas("rf605_profilell","rf605_profilell",800, 400);

  c->Divide(2);

  c->cd(1) ; gPad->SetLeftMargin(0.15) ; frame1->GetYaxis()->SetTitleOffset(1.4) ; frame1->Draw() ;

  c->cd(2) ; gPad->SetLeftMargin(0.15) ; frame2->GetYaxis()->SetTitleOffset(1.4) ; frame2->Draw() ;


  delete pll_frac ;

  delete pll_sigmag2 ;

  delete nll ;

}