run_ana_sttcombi.C

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void run_ana_sttcombi(TString fname="pid_sttcombi.root",int nevts=0)
{
        TStopwatch timer;
        timer.Start();
        
        gROOT->Macro("$VMCWORKDIR/gconfig/rootlogon.C");
        
        TCanvas *c1=new TCanvas("c1","c1",600,600);
        
        // the PndEventReader takes care about file/event handling
        PndEventReader evr(fname);
        
        // to attach more files: evr.Add(fname2);evr.Add(fname3); ...
        TH1F *invmass=new TH1F("invmass","invariant mass",400,0.0,5.0);
        
        // the candidates lists we need
        TCandList p1;
        TCandList p2;
        TCandList jpsi;
                
        if (nevts==0) nevts=evr.GetEntries();
        cout << "nevts " << nevts << "\n";
        int i=0,j=0, k=0, l=0;
        
        // *************
        // this is the loop through the events ... as simple as this...
        // ****************
        while (evr.GetEvent() && i++<nevts)
        {

//          evr.FillList(p1,"All");
//          evr.FillList(p2,"All");
            evr.FillList(p1,"Charged");
            evr.FillList(p2,"Charged");

            cout << p1.GetLength() << " e+ candidates found" << "\n";
            cout << p2.GetLength() << " e- candidates found" << "\n";

            for (j=0;j<p1.GetLength();++j) { 
                p1[j].SetMass(TRho::Instance()->GetPDG()->GetParticle(11)->Mass());
            }
            for (j=0;j<p2.GetLength();++j) { 
                p2[j].SetMass(TRho::Instance()->GetPDG()->GetParticle(11)->Mass());
            }

            jpsi.Combine(p1,p2);

            cout << jpsi.GetLength() << " J/Psi candidates found" << "\n";

            for (l=0;l<jpsi.GetLength();++l) { 
                invmass->Fill(jpsi[l].M());
            }
        }
        
        // ... and plot it
        c1->cd(); invmass->Draw();
        
        // now take the time...
        timer.Stop();
        Double_t rtime = timer.RealTime();
        Double_t ctime = timer.CpuTime();       
        printf("RealTime=%f seconds, CpuTime=%f seconds\n",rtime,ctime);

}