Analysis/VertexFit/include/VertexFit/BField.h

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#ifndef VertexFit_BField_H
#define VertexFit_BField_H
 
//
// Read field from MagneticField Service in Gaudi framework
// Author: Min Xu  data: 4/16/2008, created
 
#include "CLHEP/Geometry/Point3D.h"
#include "CLHEP/Matrix/Vector.h"
#ifndef ENABLE_BACKWARDS_COMPATIBILITY
typedef HepGeom::Point3D<double> HepPoint3D;
#endif
 
#ifndef BEAN
#  include "MagneticFieldSvc/IBesMagFieldSvc.h"
#else
#  include "MagneticField/MagneticFieldSvc.h"
#endif
 
using CLHEP::HepVector;
 
class VertexFitBField {
public:
  static VertexFitBField* instance() {
    if ( s_bfield == 0 ) { s_bfield = new VertexFitBField(); }
    return s_bfield;
  }
  // constructor & deconstructor
  ~VertexFitBField() {}
 
  double getBFieldZ( const HepPoint3D& vtx );
  double getBFieldZRef();
  // get B*c = B*-0.00299792458
  double getCBz( const HepVector& vtx, const HepVector& trackPosition );
 
private:
  VertexFitBField();
 
#ifndef BEAN
  IBesMagFieldSvc* m_pIMF;
#else
  MagneticFieldSvc* m_pIMF;
#endif
 
  static VertexFitBField* s_bfield;
  static const double     alpha;
};
#endif