doc/v606/rf705__linearmorph_8C.html

#ifndef __CINT__

#include "RooGlobalFunc.h"

#endif

#include "RooRealVar.h"

#include "RooDataSet.h"

#include "RooGaussian.h"

#include "RooConstVar.h"

#include "RooPolynomial.h"

#include "RooIntegralMorph.h"

#include "RooNLLVar.h"

#include "TCanvas.h"

#include "TAxis.h"

#include "RooPlot.h"

#include "TH1.h"

using namespace RooFit ;


void rf705_linearmorph()

{

  // C r e a t e   e n d   p o i n t   p d f   s h a p e s

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


  // Observable

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


  // Lower end point shape: a Gaussian

  RooRealVar g1mean("g1mean","g1mean",-10) ;

  RooGaussian g1("g1","g1",x,g1mean,RooConst(2)) ;


  // Upper end point shape: a Polynomial

  RooPolynomial g2("g2","g2",x,RooArgSet(RooConst(-0.03),RooConst(-0.001))) ;


  // C r e a t e   i n t e r p o l a t i n g   p d f

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


  // Create interpolation variable

  RooRealVar alpha("alpha","alpha",0,1.0) ;


  // Specify sampling density on observable and interpolation variable

  x.setBins(1000,"cache") ;

  alpha.setBins(50,"cache") ;


  // Construct interpolating pdf in (x,a) represent g1(x) at a=a_min

  // and g2(x) at a=a_max

  RooIntegralMorph lmorph("lmorph","lmorph",g1,g2,x,alpha) ;


  // P l o t   i n t e r p o l a t i n g   p d f   a t   v a r i o u s   a l p h a

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


  // Show end points as blue curves

  RooPlot* frame1 = x.frame() ;

  g1.plotOn(frame1) ;

  g2.plotOn(frame1) ;


  // Show interpolated shapes in red

  alpha.setVal(0.125) ;

  lmorph.plotOn(frame1,LineColor(kRed)) ;

  alpha.setVal(0.25) ;

  lmorph.plotOn(frame1,LineColor(kRed)) ;

  alpha.setVal(0.375) ;

  lmorph.plotOn(frame1,LineColor(kRed)) ;

  alpha.setVal(0.50) ;

  lmorph.plotOn(frame1,LineColor(kRed)) ;

  alpha.setVal(0.625) ;

  lmorph.plotOn(frame1,LineColor(kRed)) ;

  alpha.setVal(0.75) ;

  lmorph.plotOn(frame1,LineColor(kRed)) ;

  alpha.setVal(0.875) ;

  lmorph.plotOn(frame1,LineColor(kRed)) ;

  alpha.setVal(0.95) ;

  lmorph.plotOn(frame1,LineColor(kRed)) ;


  // S h o w   2 D   d i s t r i b u t i o n   o f   p d f ( x , a l p h a )

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


  // Create 2D histogram

  TH1* hh = lmorph.createHistogram("hh",x,Binning(40),YVar(alpha,Binning(40))) ;

  hh->SetLineColor(kBlue) ;


  // F i t   p d f   t o   d a t a s e t   w i t h   a l p h a = 0 . 8

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


  // Generate a toy dataset at alpha = 0.8

  alpha=0.8 ;

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


  // Fit pdf to toy data

  lmorph.setCacheAlpha(kTRUE) ;

  lmorph.fitTo(*data,Verbose(kTRUE)) ;


  // Plot fitted pdf and data overlaid

  RooPlot* frame2 = x.frame(Bins(100)) ;

  data->plotOn(frame2) ;

  lmorph.plotOn(frame2) ;


  // S c a n   - l o g ( L )   v s   a l p h a

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


  // Show scan -log(L) of dataset w.r.t alpha

  RooPlot* frame3 = alpha.frame(Bins(100),Range(0.1,0.9)) ;


  // Make 2D pdf of histogram

  RooNLLVar nll("nll","nll",lmorph,*data) ;

  nll.plotOn(frame3,ShiftToZero()) ;


  lmorph.setCacheAlpha(kFALSE) ;


  TCanvas* c = new TCanvas("rf705_linearmorph","rf705_linearmorph",800,800) ;

  c->Divide(2,2) ;

  c->cd(1) ; gPad->SetLeftMargin(0.15) ; frame1->GetYaxis()->SetTitleOffset(1.6) ; frame1->Draw() ;

  c->cd(2) ; gPad->SetLeftMargin(0.20) ; hh->GetZaxis()->SetTitleOffset(2.5) ; hh->Draw("surf") ;

  c->cd(3) ; gPad->SetLeftMargin(0.15) ; frame3->GetYaxis()->SetTitleOffset(1.4) ; frame3->Draw() ;

  c->cd(4) ; gPad->SetLeftMargin(0.15) ; frame2->GetYaxis()->SetTitleOffset(1.4) ; frame2->Draw() ;


  return ;


}