Reconstruction/MdcPatRec/MdcGeom/include/MdcGeom/MdcSagTraj.h

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//--------------------------------------------------------------------------
// File and Version Information:
//  $Id: MdcSagTraj.h,v 1.3 2009/12/17 00:38:40 zhangy Exp $
//
// Description:
//  Class MdcSagTraj.
//      the flight length at the moment is the flight length of a linear
//      trajectory, the sag is approximated with a parabola (for the
//      moment, maybe at a later time we can replace with a more accurate
//      description, cosh for example)
//
//
// Environment:
//  Software developed for the BaBar Detector at the SLAC B-Factory.
//
// Author List:
//  R. Stroili      originator
//
//
// Copyright Information:
//  Copyright (C) 1998  INFN & Padova University
//
// History:
//  Migration for BESIII MDC
//
//------------------------------------------------------------------------
 
#ifndef DCHSAGTRAJ_H
#define DCHSAGTRAJ_H
 
//-------------
// C Headers --
//-------------
extern "C" {}
 
//---------------
// C++ Headers --
//---------------
 
//----------------------
// Base Class Headers --
//----------------------
#include "MdcGeom/TrkGeomTraj.h"
 
//-------------------------------
// Collaborating Class Headers --
//-------------------------------
#include "CLHEP/Geometry/Point3D.h"
#ifndef ENABLE_BACKWARDS_COMPATIBILITY
typedef HepGeom::Point3D<double> HepPoint3D;
#endif
#include "CLHEP/Vector/ThreeVector.h"
using CLHEP::Hep3Vector;
 
//------------------------------------
// Collaborating Class Declarations --
//------------------------------------
class Trajectory;
 
//      ---------------------
//      -- Class Interface --
//      ---------------------
 
class MdcSagTraj : public TrkGeomTraj {
 
public:
  // Constructors
  MdcSagTraj( const double sag, const HepPoint3D& point1, const HepPoint3D& point2 );
  MdcSagTraj( const MdcSagTraj& traj );
 
  MdcSagTraj* clone() const;
  // Destructor
  virtual ~MdcSagTraj();
 
  // Operators
  MdcSagTraj& operator=( const MdcSagTraj& );
 
  double sag( void ) const { return _sag; }
 
  // needed implementations for intersection with a Surface
  HepPoint3D        position( double ) const;
  Hep3Vector        direction( double ) const;
  double            curvature( double f = 0. ) const;
  Hep3Vector        delDirect( double ) const;
  const Hep3Vector& rawDirection( void ) const { return _direction; }
  void              getInfo( double fltLen, HepPoint3D&, Hep3Vector& direction ) const;
  void              getInfo( double fltLen, HepPoint3D&, Hep3Vector& direction,
                             Hep3Vector& delDirect ) const;
 
  virtual double distTo1stError( double s, double tol, int pathDir ) const;
  virtual double distTo2ndError( double s, double tol, int pathDir ) const;
  double         deltaY( double fltLen ) const { return ( _a * fltLen + _b ) * fltLen; }
  // Support Visitor pattern (see TrkGeomTraj.h)
  void accept( TrkGeomTrajVisitor& visitor ) const;
 
  //    virtual int operator==( const MdcSagTraj& ) const;
  //            int operator!=( const MdcSagTraj& ) const;
 
private:
  // Data members
  double _sag;
  double _a;
  double _b;
  double _length;
  //   double _a_H;
  //   double _b_H;
  HepPoint3D _start;     // where the trajectory starts
  HepPoint3D _stop;      // where the trajectory stops
  Hep3Vector _direction; // direction (unit) vector for
                         // null sag (straight line)
 
  Hep3Vector deviation( double ) const; // displacement from the line trajectory
                                        // at a given flightlength
  // Note: if your class needs a copy constructor or an assignment operator,
  //   make one of the following public and implement it.
  //   MdcSagTraj( const MdcSagTraj& );       // Copy Constructor
  //   MdcSagTraj&       operator= ( const MdcSagTraj& );  // Assignment op
};
 
#endif // DCHSAGTRAJ_H