rf206_treevistools.C

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/// \file
/// \ingroup tutorial_roofit
/// \notebook -nodraw
///  'ADDITION AND CONVOLUTION' RooFit tutorial macro #206
///
///  Tools for visualization of RooAbsArg expression trees
///
/// \macro_output
/// \macro_code
/// \author 07/2008 - Wouter Verkerke 


#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooChebychev.h"
#include "RooAddPdf.h"
#include "RooExponential.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "RooPlot.h"
using namespace RooFit ;


void rf206_treevistools()
{
   // S e t u p   c o m p o s i t e    p d f
   // --------------------------------------

   // Declare observable x
   RooRealVar x("x","x",0,10) ;

   // Create two Gaussian PDFs g1(x,mean1,sigma) anf g2(x,mean2,sigma) and their parameters
   RooRealVar mean("mean","mean of gaussians",5) ;
   RooRealVar sigma1("sigma1","width of gaussians",0.5) ;
   RooRealVar sigma2("sigma2","width of gaussians",1) ;
   RooGaussian sig1("sig1","Signal component 1",x,mean,sigma1) ;  
   RooGaussian sig2("sig2","Signal component 2",x,mean,sigma2) ;  

   // Sum the signal components into a composite signal p.d.f.
   RooRealVar sig1frac("sig1frac","fraction of component 1 in signal",0.8,0.,1.) ;
   RooAddPdf sig("sig","Signal",RooArgList(sig1,sig2),sig1frac) ;

   // Build Chebychev polynomial p.d.f.  
   RooRealVar a0("a0","a0",0.5,0.,1.) ;
   RooRealVar a1("a1","a1",0.2,0.,1.) ;
   RooChebychev bkg1("bkg1","Background 1",x,RooArgSet(a0,a1)) ;

   // Build expontential pdf
   RooRealVar alpha("alpha","alpha",-1) ;
   RooExponential bkg2("bkg2","Background 2",x,alpha) ;

   // Sum the background components into a composite background p.d.f.
   RooRealVar bkg1frac("bkg1frac","fraction of component 1 in background",0.2,0.,1.) ;
   RooAddPdf bkg("bkg","Signal",RooArgList(bkg1,bkg2),bkg1frac) ;

   // Sum the composite signal and background 
   RooRealVar bkgfrac("bkgfrac","fraction of background",0.5,0.,1.) ;
   RooAddPdf  model("model","g1+g2+a",RooArgList(bkg,sig),bkgfrac) ;


   // P r i n t   c o m p o s i t e   t r e e   i n   A S C I I 
   // -----------------------------------------------------------

   // Print tree to stdout
   model.Print("t") ;

   // Print tree to file
   model.printCompactTree("","rf206_asciitree.txt") ;


   // D r a w   c o m p o s i t e   t r e e   g r a p h i c a l l y 
   // -------------------------------------------------------------

   // Print GraphViz DOT file with representation of tree
   model.graphVizTree("rf206_model.dot") ;

   // Make graphic output file with one of the GraphViz tools
   // (freely available from www.graphviz.org)
   //
   // 'Top-to-bottom graph'
   // unix> dot -Tgif -o rf207_model_dot.gif rf207_model.dot
   //
   // 'Spring-model graph'
   // unix> fdp -Tgif -o rf207_model_fdp.gif rf207_model.dot

}