TrkVertexFitterUtils

Author

Kiril.nosp@m.l.Pr.nosp@m.okofi.nosp@m.ev@c.nosp@m.ern.c.nosp@m.h

Introduction

This package contains a set of tools required for various vertex fitting applications. Most of theses tools are descendants of abstract interfaces defined in TrkVertexFitterInterfaces package. The tools are completely independent and can be used together or separately from each other. For a brief description of tools see below. For examples of use of these utils see TrkVertexFitters package.

Design

Trk::Chi2TrackCompatibilityEstimator A concrete implementation of Trk::IVertexTrackCompatibilityEstimator. Estimates the compatibility a track to a vertex candidate using a chi2 method: constructs the chi2 using a distance of a closest approach and a covariance matrix of a track.

Trk::DetAnnealingMaker A concrete implementation of Trk::IVertexAnnealingMaker. Represents an annealing procedure to be applied in adaptive fits. The actual annealing schedule (a set of temperatures) is a property of this tool and can be set up through the jobOptions.

Trk::DummyAnnealingMaker A dummy implementation of Trk::IVertexAnnealingMaker. The reasons for this class existence are purely technical, moreover it may quite possibly disappear at later stages.

Trk::FullLinearizedTrackFactory A helper class, used to calculated the parameters of expansion of the measurement equation at the point of closest approach. The result is then stored in Trk::LinearizedTrack object and returned to the user (typically vertex fitter).

Trk::ImpactPoint3dAtaPlaneFactory A helper class creating a parameters of track at 3D point of closest approach to a given point (e.g. vertex).

Trk::ImpactPoint3dEstimator A helper class finding a 3D point of closest approach of a track to the given reference point (e.g. vertex).

Trk::KalmanVertexTrackUpdator A concrete implementation of a Trk::IVertexSmoother. A Kalman smoother for tracks fitted to a vertex. Constrains a provided track to pass exactly through the position of a reconstructed vertex. Thus the state of the track is updated with the knowledge of its point of origin.

Trk::KalmanVertexUpdator A concrete implementation of a Trk::IVertexUpdator. A Kalman updator for vertexing. Adds or removes a single track to the vertex candidate, calculates the new position and covariance matrix of the vertex.