TrackSmearer.h

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/************
 Still needs:

 - two FIXMEs to be checked with ELzbieta
 
 - interfacing to smearing parameters
************/

// ================================================
// TrackSmearer class description
// ================================================
//
// THIS TEXT TO BE REPLACED BY ATLAS STANDARD FORMAT
//
//
// This version....
//
//
// Namespace Atlfast::
//
// class: TrackSmearer
//
// Description: 
//
//  Used to smear track helix parameters
//
//  Takes as input a set of helix parameters, and smears using a 
//  parameterised set of correclated resolutions which are input from 
//  an external source
//   
// ................................................................
//

#ifndef ATLFAST_TRACKSMEARER_H
#define ATLFAST_TRACKSMEARER_H

// CLHEP includes
#include "CLHEP/Random/RandGauss.h"
#include "CLHEP/Random/JamesRandom.h"
#include "CLHEP/Matrix/SymMatrix.h"

// Athena stuff
#include "GaudiKernel/ISvcLocator.h"
#include "GaudiKernel/IAlgorithm.h"
#include "GaudiKernel/Algorithm.h"
#include "GaudiKernel/MsgStream.h"
#include "GaudiKernel/DataObject.h"
#include "GaudiKernel/ObjectVector.h"
#include "AIDA/IHistogram1D.h"
#include "AIDA/IHistogram2D.h"
#include "GaudiKernel/IHistogramSvc.h"

// Temporary until standard way of using matrices is sorted

#include <string>

//#include "AtlfastUtils/TMatrix.h"
#include "GaudiKernel/DataSvc.h"

// Atlfast includes
#include "AtlfastEvent/Track.h"
#include "AtlfastEvent/ChargeService.h"
#include "AtlfastEvent/MagField.h"
#include "AtlfastEvent/MsgStreamDefs.h"

#include "CLHEP/Matrix/SymMatrix.h"

using ::HepSymMatrix;

namespace Atlfast {
  
  class IMatrixManager;
  
  class TrackSmearer {

  private:

    void makeMatrixManagers(int randSeed);
    void makeChargeService();
    IMatrixManager* getCorrectMatrixManager(int& pdg) const;
    
    MsgStream& m_log;
    std::string m_muonParamFile;
    std::string m_pionParamFile;
    std::string m_electronParamFile;
    std::string m_bremParamFile;

    // Matrix managers
    IMatrixManager* m_muonMatrixManager;   
    IMatrixManager* m_pionMatrixManager;   
    IMatrixManager* m_electronMatrixManager;   

    // Charge Service
    ChargeService* m_chargeService;

  public:
    
    // Constructor
    TrackSmearer( int randSeed, 
                  MsgStream& log,
                  std::string muonParFile     = "atlfastDatafiles/Atlfast_MuonResParam_CSC.dat",
                  std::string pionParFile     = "atlfastDatafiles/Atlfast_PionResParam_DC1_NewUnits.dat",
                  std::string electronParFile = "atlfastDatafiles/Atlfast_ElectronResParam_CSC.dat",
                  std::string bremParFile     = "atlfastDatafiles/Atlfast_ElectronBremParam_CSC.dat" );
    
    // Destructor
    ~TrackSmearer() ;
    
    // New interface to client which wraps old interface SmearParameters
    Track smear(const Track& track) const;
    
    // Method to convert covariance matrix into the representation used 
    // by Common Tracking, i.e. (d0, z0, phi0, theta0, q/p), instead of 
    // internally used (d0, z0, phi0, cot(theta0), q/pT). Needed when  
    // matrix is written to CBNTs or AODs.  
    HepSymMatrix convertToComTrk(const Track& track, const HepSymMatrix& sigma) const;

    double getPtResolution(const HepMC::GenParticle& particle);
    
  };
  
} // end namespace

#endif

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