Trk::StraightLineIntersector Class Reference

#include <StraightLineIntersector.h>

Inheritance diagram for Trk::StraightLineIntersector:

Collaboration diagram for Trk::StraightLineIntersector:

Public Member Functions
	StraightLineIntersector (const std::string &type, const std::string &name, const IInterface *parent)
virtual StatusCode	finalize () override
virtual std::optional< TrackSurfaceIntersection >	intersectSurface (const Surface &surface, const TrackSurfaceIntersection &trackTrackSurfaceIntersection, const double qOverP) const override
	IIntersector interface method for general Surface type.
virtual std::optional< TrackSurfaceIntersection >	approachPerigeeSurface (const PerigeeSurface &surface, const TrackSurfaceIntersection &trackTrackSurfaceIntersection, const double) const override
	IIntersector interface method for specific Surface type : PerigeeSurface.
virtual std::optional< TrackSurfaceIntersection >	approachStraightLineSurface (const StraightLineSurface &surface, const TrackSurfaceIntersection &trackTrackSurfaceIntersection, const double) const override
	IIntersector interface method for specific Surface type : StraightLineSurface.
virtual std::optional< TrackSurfaceIntersection >	intersectCylinderSurface (const CylinderSurface &surface, const TrackSurfaceIntersection &trackTrackSurfaceIntersection, const double) const override
	IIntersector interface method for specific Surface type : CylinderSurface.
virtual std::optional< TrackSurfaceIntersection >	intersectDiscSurface (const DiscSurface &surface, const TrackSurfaceIntersection &trackTrackSurfaceIntersection, const double) const override
	IIntersector interface method for specific Surface type : DiscSurface.
virtual std::optional< TrackSurfaceIntersection >	intersectPlaneSurface (const PlaneSurface &surface, const TrackSurfaceIntersection &trackTrackSurfaceIntersection, const double) const override
	IIntersector interface method for specific Surface type : PlaneSurface.
virtual bool	isValid (Amg::Vector3D, Amg::Vector3D) const override
	IIntersector interface method for validity check over a particular extrapolation range.

Private Member Functions
double	distanceToCylinder (const TrackSurfaceIntersection &isect, const double cylinderRadius) const
double	distanceToDisc (const TrackSurfaceIntersection &isect, const double discZ) const
double	distanceToLine (const TrackSurfaceIntersection &isect, const Amg::Vector3D &linePosition, const Amg::Vector3D &lineDirection) const
double	distanceToPlane (const TrackSurfaceIntersection &isect, const Amg::Vector3D &planePosition, const Amg::Vector3D &planeNormal) const
void	step (TrackSurfaceIntersection &isect, double stepLength) const

Private Attributes
std::atomic< unsigned long long >	m_countExtrapolations

Detailed Description

Definition at line 22 of file StraightLineIntersector.h.

Constructor & Destructor Documentation

StraightLineIntersector()

Trk::StraightLineIntersector::StraightLineIntersector	(	const std::string &	type,
		const std::string &	name,
		const IInterface *	parent )

Definition at line 26 of file StraightLineIntersector.cxx.

    :   base_class      (type, name, parent),
    m_countExtrapolations  (0)
{
}

Member Function Documentation

approachPerigeeSurface()

std::optional< Trk::TrackSurfaceIntersection > Trk::StraightLineIntersector::approachPerigeeSurface ( const PerigeeSurface & surface, const TrackSurfaceIntersection & trackTrackSurfaceIntersection, const double  ) const

overridevirtual

IIntersector interface method for specific Surface type : PerigeeSurface.

Definition at line 78 of file StraightLineIntersector.cxx.

{
  TrackSurfaceIntersection isect = trackIntersection;
  ++m_countExtrapolations;
 
  // straight line distance along track to closest approach to line
  const Amg::Vector3D& lineDirection = surface.transform().rotation().col(2);
  double stepLength = distanceToLine (isect, surface.center(),lineDirection);
  step(isect, stepLength);
    
  return isect;
}

approachStraightLineSurface()

std::optional< Trk::TrackSurfaceIntersection > Trk::StraightLineIntersector::approachStraightLineSurface ( const StraightLineSurface & surface, const TrackSurfaceIntersection & trackTrackSurfaceIntersection, const double  ) const

overridevirtual

IIntersector interface method for specific Surface type : StraightLineSurface.

Definition at line 95 of file StraightLineIntersector.cxx.

{
  TrackSurfaceIntersection isect = trackIntersection;
  ++m_countExtrapolations;
 
  // straight line distance along track to closest approach to line
  const Amg::Vector3D& lineDirection = surface.transform().rotation().col(2);
  double stepLength = distanceToLine (isect, surface.center(),lineDirection);
  step(isect, stepLength);
 
  return isect;
}

distanceToCylinder()

double Trk::StraightLineIntersector::distanceToCylinder ( const TrackSurfaceIntersection & isect, const double cylinderRadius ) const

inlineprivate

Definition at line 95 of file StraightLineIntersector.h.

                                                                              {
  const Amg::Vector3D& pos = isect.position();
  const Amg::Vector3D& dir = isect.direction();
  double sinThsqinv = 1. / dir.perp2();
  double stepLength = (-pos.x() * dir.x() - pos.y() * dir.y()) * sinThsqinv;
  double deltaRSq =
      (cylinderRadius * cylinderRadius - pos.perp2()) * sinThsqinv +
      stepLength * stepLength;
  if (deltaRSq > 0.)
    stepLength += sqrt(deltaRSq);
  return stepLength;
}

distanceToDisc()

double Trk::StraightLineIntersector::distanceToDisc ( const TrackSurfaceIntersection & isect, const double discZ ) const

inlineprivate

Definition at line 109 of file StraightLineIntersector.h.

                                                                     {
  const Amg::Vector3D& pos = isect.position();
  const Amg::Vector3D& dir = isect.direction();
  return (discZ - pos.z()) / dir.z();
}

distanceToLine()

double Trk::StraightLineIntersector::distanceToLine ( const TrackSurfaceIntersection & isect, const Amg::Vector3D & linePosition, const Amg::Vector3D & lineDirection ) const

inlineprivate

Definition at line 116 of file StraightLineIntersector.h.

                                            {
  // offset joining track to line is given by
  //   offset = linePosition + a*lineDirection - trackPosition -
  //   b*trackDirection
  //
  // offset is perpendicular to both line and track at solution i.e.
  //   lineDirection.dot(offset) = 0
  //   trackDirection.dot(offset) = 0
  const Amg::Vector3D& pos = isect.position();
  const Amg::Vector3D& dir = isect.direction();
  double cosAngle = lineDirection.dot(dir);
  return (linePosition - pos).dot(dir - lineDirection * cosAngle) /
         (1. - cosAngle * cosAngle);
}

distanceToPlane()

double Trk::StraightLineIntersector::distanceToPlane ( const TrackSurfaceIntersection & isect, const Amg::Vector3D & planePosition, const Amg::Vector3D & planeNormal ) const

inlineprivate

Definition at line 133 of file StraightLineIntersector.h.

                                          {
  // take the normal component of the offset from track position to plane
  // position this is equal to the normal component of the required distance
  // along the track direction
  const Amg::Vector3D& pos = isect.position();
  const Amg::Vector3D& dir = isect.direction();
  return planeNormal.dot(planePosition - pos) / planeNormal.dot(dir);
}

finalize()

StatusCode Trk::StraightLineIntersector::finalize ( )

overridevirtual

Definition at line 35 of file StraightLineIntersector.cxx.

{
    ATH_MSG_DEBUG( "finalized after " << m_countExtrapolations << " extrapolations" );
    return StatusCode::SUCCESS;
}

intersectCylinderSurface()

std::optional< Trk::TrackSurfaceIntersection > Trk::StraightLineIntersector::intersectCylinderSurface ( const CylinderSurface & surface, const TrackSurfaceIntersection & trackTrackSurfaceIntersection, const double  ) const

overridevirtual

IIntersector interface method for specific Surface type : CylinderSurface.

Definition at line 112 of file StraightLineIntersector.cxx.

{
  TrackSurfaceIntersection isect = trackIntersection;
  ++m_countExtrapolations;
  
  // calculate straight line distance along track to intersect with cylinder radius
  double cylinderRadius = surface.globalReferencePoint().perp();
  double stepLength = distanceToCylinder(isect, cylinderRadius);
  step(isect, stepLength);
 
  return isect;
}

intersectDiscSurface()

std::optional< Trk::TrackSurfaceIntersection > Trk::StraightLineIntersector::intersectDiscSurface ( const DiscSurface & surface, const TrackSurfaceIntersection & trackTrackSurfaceIntersection, const double  ) const

overridevirtual

IIntersector interface method for specific Surface type : DiscSurface.

Definition at line 129 of file StraightLineIntersector.cxx.

{
  TrackSurfaceIntersection isect = trackIntersection;
  ++m_countExtrapolations;
 
  // straight line distance along track to intersect with disc
  double stepLength = distanceToDisc(isect, surface.center().z());
  step(isect, stepLength);
  
  return isect;
}

intersectPlaneSurface()

std::optional< Trk::TrackSurfaceIntersection > Trk::StraightLineIntersector::intersectPlaneSurface ( const PlaneSurface & surface, const TrackSurfaceIntersection & trackTrackSurfaceIntersection, const double  ) const

overridevirtual

IIntersector interface method for specific Surface type : PlaneSurface.

Definition at line 145 of file StraightLineIntersector.cxx.

{
  TrackSurfaceIntersection isect = trackIntersection;
  ++m_countExtrapolations;
 
  // straight line distance along track to intersect with plane
  double stepLength = distanceToPlane (isect, surface.center(),surface.normal());
  step(isect, stepLength);
  stepLength = distanceToPlane (isect, surface.center(),surface.normal());
 
  return isect;
}

intersectSurface()

std::optional< Trk::TrackSurfaceIntersection > Trk::StraightLineIntersector::intersectSurface ( const Surface & surface, const TrackSurfaceIntersection & trackTrackSurfaceIntersection, const double qOverP ) const

overridevirtual

IIntersector interface method for general Surface type.

Definition at line 43 of file StraightLineIntersector.cxx.

{
 
    const auto surfaceType = surface.type();
    if (surfaceType == Trk::SurfaceType::Plane) {
      return intersectPlaneSurface(static_cast<const PlaneSurface&>(surface),
                                   trackIntersection, qOverP);
    }
    if (surfaceType == Trk::SurfaceType::Line) {
      return approachStraightLineSurface(
          static_cast<const StraightLineSurface&>(surface), trackIntersection,
          qOverP);
    }
    if (surfaceType == Trk::SurfaceType::Cylinder) {
      return intersectCylinderSurface(
          static_cast<const CylinderSurface&>(surface), trackIntersection,
          qOverP);
    }
    if (surfaceType == Trk::SurfaceType::Disc) {
      return intersectDiscSurface(static_cast<const DiscSurface&>(surface),
                                  trackIntersection, qOverP);
    }
    if (surfaceType == Trk::SurfaceType::Perigee) {
      return approachPerigeeSurface(static_cast<const PerigeeSurface&>(surface),
                                    trackIntersection, qOverP);
    }
 
    ATH_MSG_WARNING( " unrecognized Surface" );
    return std::nullopt;
}

isValid()

virtual bool Trk::StraightLineIntersector::isValid ( Amg::Vector3D , Amg::Vector3D  ) const

inlineoverridevirtual

IIntersector interface method for validity check over a particular extrapolation range.

Definition at line 70 of file StraightLineIntersector.h.

                                                     {
    return true;
  }

step()

void Trk::StraightLineIntersector::step ( TrackSurfaceIntersection & isect, double stepLength ) const

inlineprivate

Definition at line 144 of file StraightLineIntersector.h.

                                                                   {
  isect.position() += stepLength * isect.direction();
  isect.pathlength() += stepLength;
}

Member Data Documentation

m_countExtrapolations

std::atomic<unsigned long long> Trk::StraightLineIntersector::m_countExtrapolations

mutableprivate

Definition at line 90 of file StraightLineIntersector.h.

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The documentation for this class was generated from the following files:

• StraightLineIntersector.h
• StraightLineIntersector.cxx