CbmStsTrackFitterIdeal.cxx

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// -------------------------------------------------------------------------
// -----                CbmStsTrackFitterIdeal source file             -----
// -----                  Created 12/05/06  by D. Kresan               -----
// -------------------------------------------------------------------------
 
#include "CbmStsTrackFitterIdeal.h"
 
#include "CbmMCTrack.h"
#include "CbmStsHit.h"
#include "CbmStsPoint.h"
#include "CbmStsTrack.h"
#include "FairRootManager.h"
#include "TClonesArray.h"
#include "TParticlePDG.h"
#include "TVector3.h"
 
#include <iostream>
 
using std::cerr;
using std::cout;
using std::endl;
 
// ---------------------------- Constructor --------------------------------
CbmStsTrackFitterIdeal::CbmStsTrackFitterIdeal()
    : fArrayMCTrack(NULL)
    , fArrayStsPoint(NULL)
    , fArrayStsHit(NULL)
    , dbPDG()
{}
// -------------------------------------------------------------------------
 
// ---------------------------- Destructor ---------------------------------
CbmStsTrackFitterIdeal::~CbmStsTrackFitterIdeal() {}
// -------------------------------------------------------------------------
 
// -------------------------- Initialisation -------------------------------
void CbmStsTrackFitterIdeal::Init()
{
    dbPDG = TDatabasePDG::Instance();
    if (NULL == dbPDG) {
        cout << "-W- CbmStsTrackFitterIdeal::Init : "
             << "Database PDG is not instantiated!" << endl;
    }
 
    FairRootManager* rootMgr = FairRootManager::Instance();
    if (NULL == rootMgr) {
        cerr << "-E- CbmStsTrackFitterIdeal::Init : "
             << "ROOT manager is not instantiated!" << endl;
        return;
    }
 
    fArrayMCTrack = (TClonesArray*)rootMgr->GetObject("MCTrack");
    if (NULL == fArrayMCTrack) {
        cout << "-W- CbmStsTrackFitterIdeal::Init : "
             << "no MC track array!" << endl;
    }
 
    fArrayStsPoint = (TClonesArray*)rootMgr->GetObject("StsPoint");
    if (NULL == fArrayStsPoint) {
        cout << "-W- CbmStsTrackFitterIdeal::Init : "
             << "no STS point array!" << endl;
    }
 
    fArrayStsHit = (TClonesArray*)rootMgr->GetObject("StsHit");
    if (NULL == fArrayStsHit) {
        cout << "-W- CbmStsTrackFitterIdeal::Init : "
             << "no STS hit array!" << endl;
    }
}
// -------------------------------------------------------------------------
 
// ------------------------ Fitting algorithm ------------------------------
Int_t CbmStsTrackFitterIdeal::DoFit(CbmStsTrack* pTrack, Int_t pidHypo)
{
    if (NULL == fArrayStsPoint || NULL == fArrayStsHit)
        return 0;
 
    // Parameters at the first plane
    Int_t hitIndex = -1;
    CbmStsHit* hit;
    Int_t pointIndex;
    if (pTrack->GetNStsHits() > 0) {
        hitIndex = pTrack->GetStsHitIndex(0);
        if (hitIndex < 0)
            return 0;
        hit = (CbmStsHit*)fArrayStsHit->At(hitIndex);
        if (NULL == hit)
            return 0;
        pointIndex = hit->GetRefIndex();
    }
    if (pointIndex < 0)
        return 0;
    CbmStsPoint* point = (CbmStsPoint*)fArrayStsPoint->At(pointIndex);
    if (NULL == point)
        return 0;
    SetTrackParam(point, pTrack->GetParamFirst());
 
    // Parameters at the last plane
    if (pTrack->GetNStsHits() > 0) {
        hitIndex = pTrack->GetStsHitIndex(pTrack->GetNStsHits() - 1);
        if (hitIndex < 0)
            return 0;
        hit = (CbmStsHit*)fArrayStsHit->At(hitIndex);
        if (NULL == hit)
            return 0;
        pointIndex = hit->GetRefIndex();
    }
    if (pointIndex < 0)
        return 0;
    point = (CbmStsPoint*)fArrayStsPoint->At(pointIndex);
    if (NULL == point)
        return 0;
    SetTrackParam(point, pTrack->GetParamLast(), 1);
 
    return 1;
}
// -------------------------------------------------------------------------
 
// -------------------------- Set track parameters -------------------------
void CbmStsTrackFitterIdeal::SetTrackParam(CbmStsPoint* point, FairTrackParam* trackParam, Int_t out)
{
    TVector3 pos;
    TVector3 mom;
    if (0 == out) {
        point->Position(pos);
        point->Momentum(mom);
    } else {
        point->PositionOut(pos);
        point->MomentumOut(mom);
    }
    trackParam->SetX(pos.X());
    trackParam->SetY(pos.Y());
    trackParam->SetZ(pos.Z());
    trackParam->SetTx(mom.X() / mom.Z());
    trackParam->SetTy(mom.Y() / mom.Z());
    Int_t mcTrackIndex = point->GetTrackID();
    if (mcTrackIndex < 0)
        return;
    CbmMCTrack* mcTrack = (CbmMCTrack*)fArrayMCTrack->At(mcTrackIndex);
    if (NULL == mcTrack)
        return;
    Int_t pdgCode = mcTrack->GetPdgCode();
    TParticlePDG* particle = dbPDG->GetParticle(pdgCode);
    if (NULL == particle)
        return;
    trackParam->SetQp(particle->Charge() / mom.Mag());
}
// -------------------------------------------------------------------------