// -------------------------------------------------------------------------
// -----                  CbmLitExtrapolator                   -----
// -----                  Created 14/08/06  by A. Lebedev              -----
// -------------------------------------------------------------------------


/** CbmLitExtrapolator.h
 *@author A.Lebedev <alebedev@jinr.ru>
 **
 ** 
 **/ 


#include "TObject.h"
#include "CbmTask.h"
#include "CbmRootManager.h"
#include "CbmField.h"
#include "CbmFieldMap.h"
#include "TVectorD.h"
#include "TMatrixD.h"
#include "TMatrixDSym.h"

#include "CbmLitState.h"


#ifndef CbmLitExtrapolatorAAAA
#define CbmLitExtrapolatorAAAA 1



class CbmLitExtrapolator:public TObject
{

public:

   CbmLitExtrapolator();

   virtual ~CbmLitExtrapolator();

   void InitMagneticField();

   void SetMethod(Int_t method) { fMethod = method; }
   Int_t GetMethod() { return fMethod; }

   void Propagate(CbmLitState &StateIn,
                  Double_t z_out,
                  Bool_t IsCovMatrix);

   //magnetic field
   CbmField* fMagneticField;
private:
   Bool_t fIsCovMatrix;

   void Extrapolate( double& zIn,
                     double pIn[5],
                     double& zNew,
                     double pOut[5],
                     double fQp[25],
                     int& istat);

   void line( CbmLitState &State,
              Double_t z_out);
          
   void parabolic( CbmLitState &State,
                   Double_t z_out);

   void rk4order( double& z_in ,
                  double* p_in ,
                  double& z_out,
                  double* p_out,
                  double* rkd,
                  int& ierror);

   void rk4fast(  double& z_in ,
                  double* p_in ,
                  double& z_out ,
                  double* p_out,
                  double* rkd,
                  int& ierror );

   void rk5order( double& z_in ,
                  double* p_in ,
                  double& error ,
                  double& z_out ,
                  double* p_out,
                  double* rkd,
                  int& ierror);

   void rk5fast(  double& z_in ,
                  double* p_in,
                  double& error,
                  double& z_out,
                  double* p_out,
                  double* rkd,
                  int& ierror);

   void rk5numde( double& z_in ,
                  double* p_in,
                  double& error,
                  double& z_out,
                  double* p_out,
                  double* rkd,
                  int& ierror);

   void rk5fast(  double& z_in,
                  double* p_in,
                  double& error,
                  double& z_out,
                  double* p_out);

   void rk4fast(  double& z_in,
                  double* p_in,
                  double& z_out,
                  double* p_out);

   // propagation  method
   Int_t fMethod;
   
   //
   Double_t fError;
   Double_t fPoint[3];
   Double_t fB[3];

   // Parameters for Runge-Kutta
   Double_t fQpCurls;
   Double_t fStepMin;
   Double_t fStepMinRK5;

   Double_t c_light;


   ClassDef(CbmLitExtrapolator,1)
};

#endif // CbmLitExtrapolator_H