rf302_utilfuncs.C

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/// \file
/// \ingroup tutorial_roofit
/// \notebook
///  'MULTIDIMENSIONAL MODELS' RooFit tutorial macro #302
///
///   Utility functions classes available for use in tailoring
///   of composite (multidimensional) pdfs
///
/// \macro_image
/// \macro_output
/// \macro_code
/// \author 07/2008 - Wouter Verkerke 


#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "RooPlot.h"
#include "RooFormulaVar.h"
#include "RooAddition.h"
#include "RooProduct.h"
#include "RooPolyVar.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "TH1.h"

using namespace RooFit ;


void rf302_utilfuncs()
{
   // C r e a t e   o b s e r v a b l e s ,   p a r a m e t e r s 
   // -----------------------------------------------------------

   // Create observables
   RooRealVar x("x","x",-5,5) ;
   RooRealVar y("y","y",-5,5) ;

   // Create parameters
   RooRealVar a0("a0","a0",-1.5,-5,5) ;
   RooRealVar a1("a1","a1",-0.5,-1,1) ;
   RooRealVar sigma("sigma","width of gaussian",0.5) ;


   // U s i n g   R o o F o r m u l a V a r   t o   t a i l o r   p d f 
   // -----------------------------------------------------------------------

   // Create interpreted function f(y) = a0 - a1*sqrt(10*abs(y))
   RooFormulaVar fy_1("fy_1","a0-a1*sqrt(10*abs(y))",RooArgSet(y,a0,a1)) ;

   // Create gauss(x,f(y),s)
   RooGaussian model_1("model_1","Gaussian with shifting mean",x,fy_1,sigma) ;  



   // U s i n g   R o o P o l y V a r   t o   t a i l o r   p d f
   // -----------------------------------------------------------------------

   // Create polynomial function f(y) = a0 + a1*y
   RooPolyVar fy_2("fy_2","fy_2",y,RooArgSet(a0,a1)) ;

   // Create gauss(x,f(y),s)
   RooGaussian model_2("model_2","Gaussian with shifting mean",x,fy_2,sigma) ;  



   // U s i n g   R o o A d d i t i o n   t o   t a i l o r   p d f 
   // -----------------------------------------------------------------------

   // Create sum function f(y) = a0 + y
   RooAddition fy_3("fy_3","a0+y",RooArgSet(a0,y)) ;

   // Create gauss(x,f(y),s)
   RooGaussian model_3("model_3","Gaussian with shifting mean",x,fy_3,sigma) ;  



   // U s i n g   R o o P r o d u c t   t o   t a i l o r   p d f 
   // -----------------------------------------------------------------------

   // Create product function f(y) = a1*y
   RooProduct fy_4("fy_4","a1*y",RooArgSet(a1,y)) ;

   // Create gauss(x,f(y),s)
   RooGaussian model_4("model_4","Gaussian with shifting mean",x,fy_4,sigma) ;  



   // P l o t   a l l   p d f s 
   // ----------------------------

   // Make two-dimensional plots in x vs y
   TH1* hh_model_1 = model_1.createHistogram("hh_model_1",x,Binning(50),YVar(y,Binning(50))) ;
   TH1* hh_model_2 = model_2.createHistogram("hh_model_2",x,Binning(50),YVar(y,Binning(50))) ;
   TH1* hh_model_3 = model_3.createHistogram("hh_model_3",x,Binning(50),YVar(y,Binning(50))) ;
   TH1* hh_model_4 = model_4.createHistogram("hh_model_4",x,Binning(50),YVar(y,Binning(50))) ;
   hh_model_1->SetLineColor(kBlue) ;
   hh_model_2->SetLineColor(kBlue) ;
   hh_model_3->SetLineColor(kBlue) ;
   hh_model_4->SetLineColor(kBlue) ;

   // Make canvas and draw RooPlots
   TCanvas *c = new TCanvas("rf302_utilfuncs","rf302_utilfuncs",800, 800);
   c->Divide(2,2);
   c->cd(1) ; gPad->SetLeftMargin(0.20) ; hh_model_1->GetZaxis()->SetTitleOffset(2.5) ; hh_model_1->Draw("surf") ;
   c->cd(2) ; gPad->SetLeftMargin(0.20) ; hh_model_2->GetZaxis()->SetTitleOffset(2.5) ; hh_model_2->Draw("surf") ;
   c->cd(3) ; gPad->SetLeftMargin(0.20) ; hh_model_3->GetZaxis()->SetTitleOffset(2.5) ; hh_model_3->Draw("surf") ;
   c->cd(4) ; gPad->SetLeftMargin(0.20) ; hh_model_4->GetZaxis()->SetTitleOffset(2.5) ; hh_model_4->Draw("surf") ;
    
}