BmnPtAnalysis.h

Go to the documentation of this file.

// BmnPtAnalysis: example analysis task - transverse momentum spectrum of primary global tracks
class BmnPtAnalysis : public FairTask
{
  public:
    BmnPtAnalysis()
        : FairTask("BmnPtAnalysis")
    {}
 
    InitStatus Init() override
    {
        // get the DST branches from the input of FairRunAna
        FairRootManager* ioman = FairRootManager::Instance();
        fGlobalTracks = (TClonesArray*)ioman->GetObject("BmnGlobalTrack");
        fInnerTracks = (TClonesArray*)ioman->GetObject("StsVector");
        fVertex = (CbmVertex*)ioman->GetObject("MpdVertex.");
        if (!fGlobalTracks || !fInnerTracks || !fVertex) {
            LOG(error) << "BmnPtAnalysis::Init(): DST branches not found, the task is deactivated";
            return kERROR;
        }
        fHistPt = new TH1D("hPt", "p_{T} of primary tracks;p_{T}, GeV/c;tracks", 100, 0., 3.);
        return kSUCCESS;
    }
 
    void Exec(Option_t* /*option*/) override
    {
        if (fVertex->GetNTracks() < 2)
            return;
        for (Int_t i = 0; i < fGlobalTracks->GetEntriesFast(); i++) {
            BmnGlobalTrack* track = (BmnGlobalTrack*)fGlobalTracks->UncheckedAt(i);
            CbmStsTrack* inner = (CbmStsTrack*)fInnerTracks->UncheckedAt(track->GetGemTrackIndex());
            if (!inner->FromVertex())   // keep the tracks used in the primary vertex fit
                continue;
            fHistPt->Fill(track->GetPt());
        }
    }
 
    void Finish() override
    {
        // write the results to the output file of run_ana_bmn.C
        FairRootManager::Instance()->GetSink()->WriteObject(fHistPt, "hPt");
    }
 
  private:
    TClonesArray* fGlobalTracks = nullptr;
    TClonesArray* fInnerTracks = nullptr;
    CbmVertex* fVertex = nullptr;
    TH1D* fHistPt = nullptr;
 
    ClassDefOverride(BmnPtAnalysis, 1);
};