GenFitExtrapolator.h

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/*
GenFitExtrapolator.h

Class definition of GenFitExtrapolator, which is used to transport the track
through the detector and magnetic field and propagate the error matrix correctly.
The magnetic field integration and energy loss effect are included.

This class will be used in the prediction step of Kalman filter.

The whole algorithm is based on the Geant4e.
The detector construction is taken from GMC by Bryan Kerns.

Author: Kun Liu, liuk@fnal.gov
Created: 10-13-2011
*/

#ifndef _GENFITEXTRAPOLATOR_H
#define _GENFITEXTRAPOLATOR_H

#include <string>
#include <TMatrixD.h>
#include <TMatrixDSym.h>
#include <TVector3.h>

#include <GlobalConsts.h>

class TGeoManager;
class PHField;

class GenFitExtrapolator
{
public:
    GenFitExtrapolator();
    ~GenFitExtrapolator();

    //bool init(std::string geometrySchema, double fMagStr = FMAGSTR, double kMagStr = KMAGSTR);
    bool init(const PHField* field, const TGeoManager *geom);

    void setInitialStateWithCov(double z_in, TMatrixD& state_in, TMatrixD& cov_in);

    void setParticleType(int type);

    void getFinalStateWithCov(TMatrixD& state_out, TMatrixD& cov_out);
    double getTravelLength() { return travelLength; }

    //void buildNumericalPropagator();
    //void getNumericalPropagator(TMatrixD& prop);
    void getPropagator(TMatrixD& prop);

    /*
     * Extrapolate to a new surface z_out
     * \param z_out target position, in cm
     */
    bool extrapolateTo(double z_out);

    double extrapolateToIP();

    void convertSVtoMP(double z, TMatrixD& state, TVector3& mom, TVector3& pos);
    void convertMPtoSV(TVector3& mom, TVector3& pos, TMatrixD& state);

    void TRSDSC(int charge, TVector3 mom_input, TVector3 pos_input);
    void TRSCSD(int charge, TVector3 mom_input, TVector3 pos_input);

    TMatrixD& getJacSD2SC() { return jac_sd2sc; }
    TMatrixD& getJacSC2SD() { return jac_sc2sd; }

    void setPropCalc(bool option) { calcProp = option; }
    void setLengthCalc(bool option) { calcLength = option; }

    void print();

private:

    static bool fullInit;

    int iParType;
    enum PropDirection {Forward, Backward};
    PropDirection direction;

//    G4String parType;
//
//    ///Geant4 stuff
//    G4ErrorPropagatorManager *g4eMgr;
//    G4ErrorPropagatorData *g4eData;
//    G4ErrorPlaneSurfaceTarget *g4eTarget;
//    G4ErrorFreeTrajState *g4eState;
//    G4ErrorMatrix g4eProp;
//    G4ErrorMode g4eMode;
//
//    ///Initial state
//    G4ThreeVector pos_i;
//    G4ThreeVector mom_i;
//    G4ErrorTrajErr cov_i;
//
//    ///Final state
//    G4ThreeVector pos_f;
//    G4ThreeVector mom_f;
//    G4ErrorTrajErr cov_f;

    TVector3 pos_i;
    TVector3 mom_i;
    TMatrixDSym cov_i;

    TVector3 pos_f;
    TVector3 mom_f;
    TMatrixDSym cov_f;

    TMatrixD jac_sd2sc;
    TMatrixD jac_sc2sd;

    bool calcProp;

    bool calcLength;
    double travelLength;

    TGeoManager* _tgeo_manager;
};

#endif