Angle3DSimple.h

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
 
#pragma once
 
#include <tracking/trackFindingVXD/filterMap/filterFramework/SelectionVariable.h>
#include <framework/geometry/B2Vector3.h>
 
#include <cmath>
 
#define ANGLE3DSIMPLE_NAME Angle3DSimple
 
namespace Belle2 {
  template <typename PointType >
  class ANGLE3DSIMPLE_NAME : public SelectionVariable< PointType, 3, double > {
  public:
    PUT_NAME_FUNCTION(ANGLE3DSIMPLE_NAME);
 
    static double value(const PointType& outerHit, const PointType& centerHit, const PointType& innerHit)
    {
 
      B2Vector3<double> outerVector(outerHit.X() - centerHit.X(), outerHit.Y() - centerHit.Y(), outerHit.Z() - centerHit.Z());
      B2Vector3<double> innerVector(centerHit.X() - innerHit.X(), centerHit.Y() - innerHit.Y(), centerHit.Z() - innerHit.Z());
 
      // fullCalc would be acos(m_vecAB.Dot(m_vecBC) / m_vecAB.Mag()*m_vecBC.Mag()), but here time-consuming parts have been neglected
      double result = outerVector.Dot(innerVector) / (outerVector.Mag2() * innerVector.Mag2());
      return (std::isnan(result) || std::isinf(result)) ? double(0) : result;
    }
  };
 
}