Reconstruction/MdcPatRec/MdcGeom/include/MdcGeom/Trajectory.h

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//--------------------------------------------------------------------------
// File and Version Information:
//      $Id: Trajectory.h,v 1.3 2010/03/25 09:54:17 zhangy Exp $
//
// Description:
//  Abstract base class to describe 3-dimensional trajectories in space.
//  Defines an interface, and provides one data member -- the pathlength
//  range for which a trejectory object is valid (infinite by default).
//  In all cases, "flightlength" = 3-d pathlength along traj.
//
//      Software developed for the BaBar Detector at the SLAC B-Factory.
//
// Author(s): Dave Brown, Steve Schaffner
//
//------------------------------------------------------------------------
#ifndef TRAJECTORY_H
#define TRAJECTORY_H
 
//----------------
//-- header --
//----------------
#include "CLHEP/Matrix/Vector.h"
#include "CLHEP/Vector/ThreeVector.h"
#include <iosfwd>
 
#include "CLHEP/Geometry/Point3D.h"
#ifndef ENABLE_BACKWARDS_COMPATIBILITY
typedef HepGeom::Point3D<double> HepPoint3D;
#endif
 
using namespace CLHEP;
 
class Trajectory {
 
public:
  //*******************
  // Constructors, etc.
  //*******************
  //       By default, the valid flight distance range is really big
  Trajectory( double lowlim, double hilim );
  virtual ~Trajectory();
 
  //**********
  //  Access
  //**********
  // As a function of the flight distance
  virtual HepPoint3D position( double ) const  = 0;
  virtual Hep3Vector direction( double ) const = 0;
  virtual Hep3Vector delDirect( double ) const = 0; // 2nd deriv. WRT pathlen
  virtual double     curvature( double ) const = 0; // = |delDirect|
  // For more efficient calling:
  virtual void getInfo( double fltLen, HepPoint3D& pos, Hep3Vector& direction ) const = 0;
  virtual void getInfo( double fltLen, HepPoint3D& pos, Hep3Vector& direction,
                        Hep3Vector& delDirect ) const                                 = 0;
 
  // How far can you go using given approximation in direction (+/- 1) pathDir
  //      before error > tolerance?  Only the sign of pathDir matters; magnitude
  //      must be 1.  Returned distance is >= 0.
  double         distTo0thError( double s, double tol, int pathDir ) const;
  virtual double distTo1stError( double s, double tol, int pathDir ) const = 0;
  virtual double distTo2ndError( double s, double tol, int pathDir ) const = 0;
 
  //  CopyOf function
  virtual Trajectory* clone() const = 0;
 
  // Range of valid flight distances:
  bool         validFlightDistance( double f, double tolerance = 0.0 ) const;
  virtual void setFlightRange( double newrange[2] );
  double       lowRange() const;
  double       hiRange() const;
  double       range() const;
  //  Print functions
 
  virtual void print( std::ostream& os ) const;
  virtual void printAll( std::ostream& os ) const;
  //**************
  // End interface
  //**************
protected:
  Trajectory& operator=( const Trajectory& );
  double      flightrange[2]; // validity range for the flight distance parameter
};
 
// inline functions
 
inline bool Trajectory::validFlightDistance( double f, double tol ) const {
  return f >= flightrange[0] - tol && f <= flightrange[1] + tol;
}
inline double Trajectory::lowRange() const { return flightrange[0]; }
inline double Trajectory::hiRange() const { return flightrange[1]; }
inline double Trajectory::range() const { return hiRange() - lowRange(); }
#endif