thailand2017/tut_ana_pid.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"


// *** routine to only keep PID matched candidates in list
int SelectTruePid(PndAnalysis *ana, RhoCandList &l)
{
        int removed = 0;
        
        for (int ii=l.GetLength()-1;ii>=0;--ii)
        {
                if ( !(ana->McTruthMatch(l[ii])) )
                {
                        l.Remove(l[ii]);
                        removed++;
                }
        }
        
        return removed;
}


void tut_ana_pid(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_pid.root","RECREATE");
        
        // #### EXERCISE:  create some histograms
        TH1F *hjpsim_all = new TH1F("hjpsim_all","J/#psi mass (all)",200,0,4.5);                   // -> no PID
        TH1F *hjpsim_lpid = new TH1F("hjpsim_lpid","J/#psi mass (loose pid)",200,0,4.5);     // -> loose PID
        // ...
        
        // ------------------------------
        // 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;
                                
                // *** combinatorics NO PID 
                
                // #### EXERCISE: ---> Fill mu+, mu-, pi+ and pi- lists 
                theAnalysis->FillList(muplus,  "MuonAllPlus");
                //...
                
                // *** combinatorics for J/psi -> mu+ mu-
                jpsi.Combine(muplus, muminus);
                fillM(jpsi, hjpsim_all);
                jpsi.Select(jpsiMassSel);
                
                // *** combinatorics for pbarp -> J/psi pi+ pi-
                pbarp.Combine(jpsi, piplus, piminus);
                
                
                // *** TRUE PID combinatorics
                
                // #### EXERCISE:  do MC truth match for PID type
                 SelectTruePid(theAnalysis, muplus);
                //....
                
                                                
                // #### EXERCISE:  all combinatorics again with true PID
                //jpsi.Combine(...
                //jpsi.Select(....
                //pbarp.Combine(...
                
                
                // #### EXERCISE:  LOOSE PID combinatorics
                
                // *** and again with PidAlgoMvd;PidAlgoStt;PidAlgoDrc and loose selection
                // theAnalysis->FillList(muplus,  "MuonLoosePlus",  "PidAlgoMvd;PidAlgoStt;PidAlgoDrc");
                // ...
                
                //jpsi.Combine(..
                //jpsi.Select(....
                //pbarp.Combine(...
                
                
                // #### EXERCISE:  TIGHT PID combinatorics
                
                // *** and again with tight selection
                // ...
                                
        }
        
        // *** 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();
}