rf207_comptools.C File Reference

Detailed Description

'ADDITION AND CONVOLUTION' RooFit tutorial macro #207

Tools and utilities for manipulation of composite objects

Processing /builddir/build/BUILD/root-6.10.02/tutorials/roofit/rf207_comptools.C...

RooFit v3.60 -- Developed by Wouter Verkerke and David Kirkby 
                Copyright (C) 2000-2013 NIKHEF, University of California & Stanford University
                All rights reserved, please read http://roofit.sourceforge.net/license.txt

  1) 0xbe958250 RooRealVar:: x = 5  L(0 - 10)  "x"
  1) 0xbe957728 RooRealVar::       a0 = 0.5  L(0 - 1)  "a0"
  2) 0xbe957490 RooRealVar::       a1 = 0.2  L(0 - 1)  "a1"
  3) 0xbe956e98 RooRealVar::    alpha = -1 C  L(-INF - +INF)  "alpha"
  4) 0xbe9568e0 RooRealVar:: bkg1frac = 0.2  L(0 - 1)  "fraction of component 1 in background"
  5) 0xbe9561a8 RooRealVar::  bkgfrac = 0.5  L(0 - 1)  "fraction of background"
  6) 0xbe957fb8 RooRealVar::     mean = 5 C  L(-INF - +INF)  "mean of gaussians"
  7) 0xbe957d20 RooRealVar::    sigma = 0.5 C  L(-INF - +INF)  "width of gaussians"
RooArgSet::parameters = (a0,a1,alpha,bkg1frac,bkgfrac,mean,sigma)
  1) 0xbe955d08 RooAddPdf:: model[ bkgfrac * bkg + [%] * sig ] = 0.582695  "g1+g2+a"
  2) 0xbe956440 RooAddPdf::   bkg[ bkg1frac * bkg1 + [%] * bkg2 ] = 0.16539  "Signal"
  3) 0xbe957130 RooChebychev::  bkg1[ x=x coefficients=(a0,a1) ] = 0.8  "Background 1"
  4) 0xbe956b78 RooExponential::  bkg2[ x=x c=alpha ] = 0.00673795  "Background 2"
  5) 0xbe9579c0 RooGaussian::   sig[ x=x mean=mean sigma=sigma ] = 1  "Signal component 1"
[#1] INFO:ObjectHandling -- RooCustomizer::build(model): tree node sig will be replaced by sigsum
[#1] INFO:ObjectHandling -- RooCustomizer::build(model) Branch node RooAddPdf::model cloned: depends on a replaced parameter
[#1] INFO:ObjectHandling -- RooCustomizer::build(model) Branch node sig is already replaced
0x81ace398 RooAddPdf::model_cust = 0.582695 [Auto,Dirty] 
  0xbe956440/V- RooAddPdf::bkg = 0.16539 [Auto,Dirty] 
    0xbe957130/V- RooChebychev::bkg1 = 0.8 [Auto,Dirty] 
      0xbe958250/V- RooRealVar::x = 5
      0xbe957728/V- RooRealVar::a0 = 0.5
      0xbe957490/V- RooRealVar::a1 = 0.2
    0xbe9568e0/V- RooRealVar::bkg1frac = 0.2
    0xbe956b78/V- RooExponential::bkg2 = 0.00673795 [Auto,Dirty] 
      0xbe958250/V- RooRealVar::x = 5
      0xbe956e98/V- RooRealVar::alpha = -1
  0xbe9561a8/V- RooRealVar::bkgfrac = 0.5
  0xbe954ba8/V- RooAddPdf::sigsum = 1 [Auto,Dirty] 
    0xbe9579c0/V- RooGaussian::sig = 1 [Auto,Dirty] 
      0xbe958250/V- RooRealVar::x = 5
      0xbe957fb8/V- RooRealVar::mean = 5
      0xbe957d20/V- RooRealVar::sigma = 0.5
    0xbe955048/V- RooRealVar::sig1frac = 0.8
    0xbe9552e0/V- RooGaussian::sig2 = 1 [Auto,Dirty] 
      0xbe958250/V- RooRealVar::x = 5
      0xbe957fb8/V- RooRealVar::mean = 5
      0xbe955640/V- RooRealVar::sigma2 = 1

#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooChebychev.h"
#include "RooExponential.h"
#include "RooAddPdf.h"
#include "RooPlot.h"
#include "RooCustomizer.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "TH1.h"
using namespace RooFit ;



void rf207_comptools()
{

   // S e t u p   c o m p o s i t e    p d f,   d a t a s e t
   // --------------------------------------------------------

   // 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 sigma("sigma","width of gaussians",0.5) ;
   RooGaussian sig("sig","Signal component 1",x,mean,sigma) ;

   // 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 exponential 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) ;



   // Create dummy dataset that has more observables than the above pdf
   RooRealVar y("y","y",-10,10) ;
   RooDataSet data("data","data",RooArgSet(x,y)) ;




   // ---------------------------------------------------
   // B a s i c   i n f o r m a t i o n   r e q u e s t s
   // ===================================================


   // G e t   l i s t   o f   o b s e r v a b l e s
   // ---------------------------------------------

   // Get list of observables of pdf in context of a dataset
   //
   // Observables are define each context as the variables
   // shared between a model and a dataset. In this case
   // that is the variable 'x'

   RooArgSet* model_obs = model.getObservables(data) ;
   model_obs->Print("v") ;


   // G e t   l i s t   o f   p a r a m e t e r s
   // -------------------------------------------

   // Get list of parameters, given list of observables
   RooArgSet* model_params = model.getParameters(x) ;
   model_params->Print("v") ;

   // Get list of parameters, given a dataset
   // (Gives identical results to operation above)
   RooArgSet* model_params2 = model.getParameters(data) ;
   model_params2->Print() ;


   // G e t   l i s t   o f   c o m p o n e n t s
   // -------------------------------------------

   // Get list of component objects, including top-level node
   RooArgSet* model_comps = model.getComponents() ;
   model_comps->Print("v") ;


   // -------------------------------------------------------------------------------
   // M o d i f i c a t i o n s   t o   s t r u c t u r e   o f   c o m p o s i t e s
   // ===============================================================================


   // Create a second Gaussian
   RooRealVar sigma2("sigma2","width of gaussians",1) ;
   RooGaussian sig2("sig2","Signal component 1",x,mean,sigma2) ;

   // Create a sum of the original Gaussian plus the new second Gaussian
   RooRealVar sig1frac("sig1frac","fraction of component 1 in signal",0.8,0.,1.) ;
   RooAddPdf sigsum("sigsum","sig+sig2",RooArgList(sig,sig2),sig1frac) ;

   // Construct a customizer utility to customize model
   RooCustomizer cust(model,"cust") ;

   // Instruct the customizer to replace node 'sig' with node 'sigsum'
   cust.replaceArg(sig,sigsum) ;

   // Build a clone of the input pdf according to the above customization
   // instructions. Each node that requires modified is clone so that the
   // original pdf remained untouched. The name of each cloned node is that
   // of the original node suffixed by the name of the customizer object
   //
   // The returned head node own all nodes that were cloned as part of
   // the build process so when cust_clone is deleted so will all other
   // nodes that were created in the process.
   RooAbsPdf* cust_clone = (RooAbsPdf*) cust.build(kTRUE) ;

   // Print structure of clone of model with sig->sigsum replacement.
   cust_clone->Print("t") ;


   delete cust_clone ;

}

Author

07/2008 - Wouter Verkerke

Definition in file rf207_comptools.C.