// ETrack.h

#ifndef ETrack_H
#define ETrack_H

// TRF track vector with error.
//
// Data includes a surface pointer _psrf, 5-vector _vec and 5 x 5
// symmetric error matrix _err.  All are managed internally.

#include "VTrack.h"

namespace trf {

class ETrack : public VTrack {

private:  // attributes

  TrackError _err;

public:  // methods

  // default constructor
  ETrack();

  // construct a track vector from a surface
#ifndef DEFECT_NO_EXPLICIT
  explicit
#endif
  ETrack(const SurfacePtr& psrf);

  // constructor from a surface, track and error matrix
  ETrack(const SurfacePtr& psrf, const TrackVector& vec,
         const TrackError& err);

  // constructor from a surface, track, error matrix and direction
  ETrack(const SurfacePtr& psrf, const TrackVector& vec,
         const TrackError& err, TrackSurfaceDirection dir);

  // Constructor from a VTrack and an error matrix.
  ETrack(const VTrack& trv, const TrackError& err);

  // copy constructor
  ETrack(const ETrack& tre);

  // destructor
  virtual ~ETrack();

  // assignment operator
  ETrack& operator=(const ETrack& tre);

  // output stream
  void ostr(std::ostream& stream) const;

  // set error matrix
  void set_error(const TrackError& newerr) { _err = newerr; }

  // get error matrix
  const TrackError& get_error() const { return _err; }

  // get a component of the error matrix
  double get_error(int i, int j) const {
    assert( i>=0 && i<5 );
    assert( j>=0 && j<5 );
    return _err(i,j);
  }

};

}  // end namespace trf

// External functions.

// output stream
std::ostream& operator<<(std::ostream& stream, const trf::ETrack& rhs );

// equality
bool operator==(const trf::ETrack& trv1, const trf::ETrack& trv2);

// inequality
bool operator!=(const trf::ETrack& trv1, const trf::ETrack& trv2);

// Get the difference between two track vectors with errors
// weighted by their combined error matrix.
double chisq_diff(const trf::ETrack& trv1, const trf::ETrack& trv2 );

// Get the difference between two track vectors with and
// without errors weighted by the error matrix.
double chisq_diff(const trf::ETrack& trv1, const trf::VTrack& trv2 );

// Get the difference between two track vectors without and
// with errors weighted by the error matrix.
double chisq_diff(const trf::VTrack& trv1, const trf::ETrack& trv2 );

#endif