LayerCrossingSide Class Reference

#include <LayerCrossingSide.h>

Public Member Functions
int	barrelSide (const TrajectoryStateOnSurface &startingState, const Propagator &prop) const
	returns 0 if barrel layer crossed from inside, 1 if from outside More...
int	endcapSide (const TrajectoryStateOnSurface &startingState, const Propagator &prop) const

Detailed Description

Helper class to determine if a TrajectoryStateOnSurface would cross a layer from the inside, or from the outside, if propagated with a propagator with a defined direction. No propagations performed, the result is very fast but not correct in case of a looping track that first goes outwards, then inwards, before crossing a layer.

Definition at line 15 of file LayerCrossingSide.h.

Member Function Documentation

int LayerCrossingSide::barrelSide ( const TrajectoryStateOnSurface &  startingState, const Propagator &  prop  ) const

inline

returns 0 if barrel layer crossed from inside, 1 if from outside

Definition at line 19 of file LayerCrossingSide.h.

References alongMomentum, Vector3DBase< T, FrameTag >::dot(), TrajectoryStateOnSurface::globalMomentum(), TrajectoryStateOnSurface::globalPosition(), oppositeToMomentum, pos, Propagator::propagationDirection(), PV3DBase< T, PVType, FrameType >::x(), and PV3DBase< T, PVType, FrameType >::y().

                                                                                              {
    GlobalPoint pos = startingState.globalPosition();
    GlobalVector radial(pos.x(), pos.y(), 0);
    if (startingState.globalMomentum().dot( radial) > 0) {  // momentum points outwards
      return (prop.propagationDirection() == alongMomentum ? 0 : 1);
    }
    else {  // momentum points inwards
      return (prop.propagationDirection() == oppositeToMomentum ? 0 : 1);
    }
  }

int LayerCrossingSide::endcapSide ( const TrajectoryStateOnSurface &  startingState, const Propagator &  prop  ) const

inline

returns 0 if endcap layer crossed from inside, ie from the side of the interation region, 1 if from outside

Definition at line 33 of file LayerCrossingSide.h.

References alongMomentum, TrajectoryStateOnSurface::globalMomentum(), TrajectoryStateOnSurface::globalPosition(), oppositeToMomentum, Propagator::propagationDirection(), and PV3DBase< T, PVType, FrameType >::z().

Referenced by TECLayer::groupedCompatibleDetsV().

                                                                                              {
    float zpos = startingState.globalPosition().z();
    if (startingState.globalMomentum().z() * zpos > 0) {  // momentum points outwards
      return (prop.propagationDirection() == alongMomentum ? 0 : 1);
    }
    else {  // momentum points inwards
      return (prop.propagationDirection() == oppositeToMomentum ? 0 : 1);
    }
  }