rf401_importttreethx.C

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/// \file
/// \ingroup tutorial_roofit
/// \notebook -nodraw
///  'DATA AND CATEGORIES' RooFit tutorial macro #401
///
///  Overview of advanced option for importing data from ROOT TTree and THx histograms
///  Basic import options are demonstrated in rf102_dataimport.C
///
/// \macro_output
/// \macro_code
/// \author 07/2008 - Wouter Verkerke 


#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooDataHist.h"
#include "RooCategory.h"
#include "RooGaussian.h"
#include "RooConstVar.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "RooPlot.h"
#include "TH1.h"
#include "TTree.h"
#include "TRandom.h"
#include <map>

using namespace RooFit ;



TH1* makeTH1(const char* name, Double_t mean, Double_t sigma) ;
TTree* makeTTree() ;


void rf401_importttreethx()
{
   // I m p o r t  m u l t i p l e   T H 1   i n t o   a   R o o D a t a H i s t
   // --------------------------------------------------------------------------

   // Create thee ROOT TH1 histograms
   TH1* hh_1 = makeTH1("hh1",0,3) ;
   TH1* hh_2 = makeTH1("hh2",-3,1) ;
   TH1* hh_3 = makeTH1("hh3",+3,4) ;

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

   // Create category observable c that serves as index for the ROOT histograms
   RooCategory c("c","c") ;
   c.defineType("SampleA") ;
   c.defineType("SampleB") ;
   c.defineType("SampleC") ;

   // Create a binned dataset that imports contents of all TH1 mapped by index category c
   RooDataHist* dh = new RooDataHist("dh","dh",x,Index(c),Import("SampleA",*hh_1),Import("SampleB",*hh_2),Import("SampleC",*hh_3)) ;
   dh->Print() ;

   // Alternative constructor form for importing multiple histograms
   map<string,TH1*> hmap ;
   hmap["SampleA"] = hh_1 ;
   hmap["SampleB"] = hh_2 ;
   hmap["SampleC"] = hh_3 ;
   RooDataHist* dh2 = new RooDataHist("dh","dh",x,c,hmap) ;
   dh2->Print() ;

   

   // I m p o r t i n g   a   T T r e e   i n t o   a   R o o D a t a S e t   w i t h   c u t s 
   // -----------------------------------------------------------------------------------------

   TTree* tree = makeTTree() ;

   // Define observables y,z
   RooRealVar y("y","y",-10,10) ;
   RooRealVar z("z","z",-10,10) ;

   // Import only observables (y,z)
   RooDataSet ds("ds","ds",RooArgSet(x,y),Import(*tree)) ;
   ds.Print() ;

   // Import observables (x,y,z) but only event for which (y+z<0) is true
   RooDataSet ds2("ds2","ds2",RooArgSet(x,y,z),Import(*tree),Cut("y+z<0")) ;
   ds2.Print() ;



   // I m p o r t i n g   i n t e g e r   T T r e e   b r a n c h e s
   // ---------------------------------------------------------------

   // Import integer tree branch as RooRealVar
   RooRealVar i("i","i",0,5) ;
   RooDataSet ds3("ds3","ds3",RooArgSet(i,x),Import(*tree)) ;
   ds3.Print() ;

   // Define category i
   RooCategory icat("i","i") ;
   icat.defineType("State0",0) ;
   icat.defineType("State1",1) ;

   // Import integer tree branch as RooCategory (only events with i==0 and i==1
   // will be imported as those are the only defined states)
   RooDataSet ds4("ds4","ds4",RooArgSet(icat,x),Import(*tree)) ;
   ds4.Print() ;



   // I m p o r t  m u l t i p l e   R o o D a t a S e t s   i n t o   a   R o o D a t a S e t 
   // ----------------------------------------------------------------------------------------

   // Create three RooDataSets in (y,z)
   RooDataSet* dsA = (RooDataSet*) ds2.reduce(RooArgSet(x,y),"z<-5") ;
   RooDataSet* dsB = (RooDataSet*) ds2.reduce(RooArgSet(x,y),"abs(z)<5") ;
   RooDataSet* dsC = (RooDataSet*) ds2.reduce(RooArgSet(x,y),"z>5") ;

   // Create a dataset that imports contents of all the above datasets mapped by index category c
   RooDataSet* dsABC = new RooDataSet("dsABC","dsABC",RooArgSet(x,y),Index(c),Import("SampleA",*dsA),Import("SampleB",*dsB),Import("SampleC",*dsC)) ;

   dsABC->Print() ;

}



TH1* makeTH1(const char* name, Double_t mean, Double_t sigma) 
{
  // Create ROOT TH1 filled with a Gaussian distribution

  TH1D* hh = new TH1D(name,name,100,-10,10) ;
  for (int i=0 ; i<1000 ; i++) {
    hh->Fill(gRandom->Gaus(mean,sigma)) ;
  }
  return hh ;
}



TTree* makeTTree() 
{
  // Create ROOT TTree filled with a Gaussian distribution in x and a uniform distribution in y

  TTree* tree = new TTree("tree","tree") ;
  Double_t* px = new Double_t ;
  Double_t* py = new Double_t ;
  Double_t* pz = new Double_t ;
  Int_t*    pi = new Int_t ;
  tree->Branch("x",px,"x/D") ;
  tree->Branch("y",py,"y/D") ;
  tree->Branch("z",pz,"z/D") ;
  tree->Branch("i",pi,"i/I") ;
  for (int i=0 ; i<100 ; i++) {
    *px = gRandom->Gaus(0,3) ;
    *py = gRandom->Uniform()*30 - 15 ;
    *pz = gRandom->Gaus(0,5) ;
    *pi = i % 3 ;
    tree->Fill() ;
  }
  return tree ;
}