thailand2017/tut_ana_mcmatch.C

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class RhoCandList;
class RhoCandidate;
class PndAnaPidSelector;
class PndAnaPidCombiner;
class PndAnalysis;

// **** some auxilliary functions in auxtut.C ****
// - FairRunAna* initrun(TString prefix, TString outfile, int min=-1, int max=-1) --> Init FairRunAna
// - plotmyhistos()               --> Plots all histograms in current TDirectory on a autosized canvas
// - writemyhistos()              --> Writes all histos in current TFile 
// - fillM(RhoCandList l, TH1* h) --> Fill mass histogram h with masses of candidates in l
// - RemoveGeoManager()           --> Temporary fix for error on macro exit   
// **** some auxilliary functions in auxtut.C ****
#include "auxtut.C"


void tut_ana_mcmatch(int nevts = 0, TString prefix = "signal")
{
        // *** some variables
        int i=0,j=0, k=0, l=0;
        gStyle->SetOptFit(1011);
        
        // *** Initialize FairRunAna with defaults      
        TString OutFile="out_dummy.root";  
        FairRunAna* fRun = initrun(prefix, OutFile);
        fRun->Init();
        
        // *** create an output file for all histograms
        TFile *out = TFile::Open(prefix+"_ana_mcmatch.root","RECREATE");
        
        // #### EXERCISE:  create some histograms
        TH1F *hjpsim_all = new TH1F("hjpsim_all","J/#psi mass",200,0,4.5);
        TH1F *hjpsim_ftm = new TH1F("hjpsim_ftm","J/#psi mass (full truth match)",200,0,4.5);
        // ...
        
        // ------------------------------
        // Now the analysis stuff comes...
        // ------------------------------
        
        
        // *** the data reader object
        PndAnalysis* theAnalysis = new PndAnalysis();
        if (nevts==0) nevts= theAnalysis->GetEntries();
        
        // *** RhoCandLists for the analysis
        RhoCandList muplus, muminus, piplus, piminus, jpsi, pbarp;
        
        // *** Mass selector for the jpsi cands
        RhoMassParticleSelector *jpsiMassSel=new RhoMassParticleSelector("jpsi",3.096,1.0);
        
        // ***
        // the event loop
        // ***
        while (theAnalysis->GetEvent() && i++<nevts)
        {
                if ((i%100)==0) cout<<"evt " << i << endl;
                
                // #### EXERCISE:  Select with no PID info ('All'); type and mass are set               
                theAnalysis->FillList(muplus,  "MuonAllPlus");
                // ...
                
                // *** combinatorics for J/psi -> mu+ mu-, AND specify PDG type as last parameter!
                jpsi.Combine(muplus, muminus, 443);
                
                // *** do the TRUTH MATCH for jpsi

                for (j=0;j<jpsi.GetLength();++j) 
                {
                        // *** fill mass in histogram
                        hjpsim_all->Fill( jpsi[j]->M() );
                        
                        // #### EXERCISE: fill mass in histogram for truth match candidates
                        if (theAnalysis->McTruthMatch(jpsi[j])) 
                        {
                                //hjpsim_ftm->Fill(...
                        }                       
                        // #### EXERCISE: fill mass in histogram for non match candidates
                        else ;
                                //...->Fill( ...
                }
                                
                // *** some rough mass selection
                jpsi.Select(jpsiMassSel);
                
                // #### EXERCISE:  combinatorics for pbarpSystem (PDG=88888) -> J/psi pi+ pi-
                // pbarp.Combine(...
                
                // *** do the TRUTH MATCH for pbarpSystem (PDG == 88888)

                for (j=0;j<pbarp.GetLength();++j) 
                {
                        // #### EXERCISE:  fill histos for pbarp candidates with and w/o MC truth match
                        
                }                       
        }
        
        // *** change to directory where histograms are created
        out->cd();

        // *** plot all histos
        plotmyhistos();
        
        // *** write out all the histos to file
        int nhist = writemyhistos();
        cout<<"Writing "<<nhist<<" histograms to file"<<endl;           
        out->Save();    
        
        // *** temporaty fix to avoid error on macro exit
        RemoveGeoManager();
}