extract_zdc_histo_from_reco.C

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/*************************************************************************************
 *  Example by: Elena Litvinenko
 *  e-mail:     litvin@nf.jinr.ru
 *  Version:    29-Jan-2016
 ************************************************************************************/
 
void extract_zdc_histo_from_reco(const char* filename = "reco_zdc.root")
{
 
    Double_t x, y, ee;
 
    TFile* f = new TFile(filename);
 
    TH2F* hist_zdc_orig = (TH2F*)f->Get("HistZdcEn");
 
    TChain chain("cbmsim");
    chain.Add(filename);
    TChain* t = &chain;
    Int_t n_events = t->GetEntries();
 
    TClonesArray* ELossZdcHisto_arr = 0;
    t->SetBranchAddress("ELossZdcHisto", &ELossZdcHisto_arr);
 
    TString main_title_zdc1 = hist_zdc_orig->GetTitle();
 
    Int_t n_entries = t->GetEntries();
    if (n_entries > 8)
        n_entries = 4;
 
    for (int i = 0; i < n_entries; i++) {
 
        t->GetEntry(i);
 
        TH2F* hist_zdc = hist_zdc_orig->Clone("hist_zdc");
 
        TVectorT<float>& v1 = *((TVectorT<float>*)ELossZdcHisto_arr->At(0));
        hist_zdc->Set(v1.GetNoElements(), v1.GetMatrixArray());
        hist_zdc->SetEntries(v1.GetNoElements());
        hist_zdc->SetTitle(Form("%s (event %d)", main_title_zdc1.Data(), i));
        cout << hist_zdc->GetTitle() << " " << hist_zdc->GetSum() << endl;
 
        if (i < 8)
            new TCanvas();
        hist_zdc->Draw("colz");
    }
}