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TrackSmearer.cxx

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#include "AtlfastAlgs/TrackSmearer.h"
#include <cmath>
#include <iostream>

#include "AtlfastAlgs/PionMatrixManager.h"
#include "AtlfastAlgs/ElectronMatrixManager.h"
#include "AtlfastAlgs/MuonMatrixManager.h"

namespace Atlfast {
  using std::abs;
  
  //----------------------------------------
  // Constructor
  //----------------------------------------
  
  TrackSmearer::TrackSmearer(const string& config, 
                             int randSeed, 
                             MsgStream& log):
    m_log(log), m_muConfig(config){
    m_electronMatrixManager = new ElectronMatrixManager(randSeed, log);
    m_muonMatrixManager = new MuonMatrixManager(m_muConfig, randSeed, log);
    m_pionMatrixManager = new PionMatrixManager(randSeed, log);
    log << MSG::INFO << "TrackSmearer constructed"<<endreq;
  }
  
  
  //------------------------------------------
  // Destructor
  //------------------------------------------
  
  TrackSmearer::~TrackSmearer(){
    if (m_pionMatrixManager) delete m_pionMatrixManager;
    if (m_electronMatrixManager) delete m_electronMatrixManager;
    if (m_muonMatrixManager) delete m_muonMatrixManager;
  }
  
  //------------------------------------------------------------------
  // PUBLIC: smear : takes track trajectory and smears its parameters
  //------------------------------------------------------------------
  Track TrackSmearer::smear(const Track& track)const{
    vector<double> smearVariables ;   // Vector of correlated gaussian variables
    // IF to determine which manager to use ie. electron/muon/pion
    IMatrixManager* correctManager = NULL;
    int pdg = abs( track.pdg_id() );
    
    if (pdg == 11) {correctManager = m_electronMatrixManager;}
    if (pdg == 13) {correctManager = m_muonMatrixManager;}
    if (pdg == 211) {correctManager = m_pionMatrixManager;}
    if(correctManager == NULL) {
      correctManager = m_pionMatrixManager;
    }
    //End IF
    TrackTrajectory originalTrajectory = track.trajectory();
    HepMatrix sigma; // smear matrix for track
    TrackParameters parameters = originalTrajectory.parameters();
    smearVariables = correctManager->getVariables(originalTrajectory, sigma);
    // smear parameters with gaussian variables

    double impactParameter = parameters.impactParameter() + smearVariables[0] ;
    double zPerigee = parameters.zPerigee() + smearVariables[1] ;
    Phi phi = parameters.phi() + smearVariables[2] ;
    double cotTheta = parameters.cotTheta() + smearVariables[3] ;
    double invPtCharge = parameters.invPtCharge() +  smearVariables[4];

    double curvature = originalTrajectory.curvature(); 
    double pT = abs( 1. / invPtCharge ) ;
    Hep3Vector vec;
    vec.setX( pT*cos(phi) );
    vec.setY( pT*sin(phi) );
    vec.setZ( pT*cotTheta );
    // Convert results to object
    TrackTrajectory smearedTrajectory( TrackParameters(vec.pseudoRapidity(), 
                                                       phi, pT, impactParameter,
                                                       zPerigee, cotTheta,
                                                       invPtCharge), 
                                       originalTrajectory.startPoint(),
                                       curvature
                                       ) ;


    //PS - tracks should always have the 4-vector
    //    Track newTrack;

    //    if (track.truth()) {
    Track newTrack(originalTrajectory, smearedTrajectory, track.truth(), sigma);
    //    }
    //    else {
    //      newTrack = Track(originalTrajectory, smearedTrajectory, sigma, track.pdg_id());
    //    }
    return newTrack ;
    
  }
} // end namespace

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