Difference: SWGuideTrimmedKalmanVertexFinder (1 vs. 2)

Revision 22009-03-11 - ThomasSpeer

Line: 1 to 1
 
META TOPICPARENT name="SWGuideOfflineSecondaryVertexFinding"

The Trimmed Kalman vertex reconstructor

Line: 23 to 23
 

Parameters

Changed:
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<
The following parameters can be defined by the following set methods:
>
>
To change the parameters, the easiest is to use the setParameters(ParameterSet) method. Alternatively, individual set methods can be used. The PSet needed is the following:
 
Changed:
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<
  • ptCut: defines the minimum pT of the tracks used to make vertices.
    default: 1.5 GeV/c
    method: setPtCut(float cut)
  • trackCompatibilityCut: defines the probability below which a track is considered incompatible with the 1st vertex candidate formed.
    default: 0.05
    method: setTrackCompatibilityCut(float cut)
  • trackCompatibilityToSV : defines the probability below which a track is considered incompatible with the next vertex candidates formed.
    default: 0.01
    method: setTrackCompatibilityToSV(float cut)
  • vertexFitProbabilityCut: defines the probability below which a vertex is rejected
    default: 0.01
    method: setVertexFitProbabilityCut(float cut)
  • maxNbOfVertices : defines the maximum number of vertices searched for. 0 means no limitations.
    default: 0
    method: setMaxNbOfVertices(int max)
>
>
GSFParameters = cms.PSet(
   ptCut = cms.double(0.0),
   vtxFitProbCut = cms.double(0.01),
   trackCompatibilityToPVcut = cms.double(0.05),
   trackCompatibilityToSVcut = cms.double(0.01),
   maxNbOfVertices = cms.int32(0)
)

The parameters are the following:

Parameter Name Description
<!-- -->
Sorted ascending
Default method
maxNbOfVertices the maximum number of vertices searched for. 0 means no limitations 0 setMaxNbOfVertices(int)
ptCut the minimum pT (in GeV) of the tracks used to make vertices. 1.5 setPtCut(float)
trackCompatibilityToPVcut the probability below which a track is considered incompatible with the 1st vertex candidate formed. 0.05 setTrackCompatibilityCut(float)
trackCompatibilityToSVcut the probability below which a track is considered incompatible with the next vertex candidates formed. 0.01 setTrackCompatibilityToSV(float)
vertexFitProbabilityCut the probability below which a vertex is rejected 0.01 setVertexFitProbabilityCut(float)
 

-- Main.speer - 05 Jul 2007 \ No newline at end of file

Revision 12007-07-05 - ThomasSpeer

Line: 1 to 1
Added:
>
>
META TOPICPARENT name="SWGuideOfflineSecondaryVertexFinding"

The Trimmed Kalman vertex reconstructor

Complete: 2

Overview

The Trimmed Kalman vertex reconstructor iteratively uses the Trimmed Kalman vertex fitter to find and fit interaction vertices. After each fitted vertex, the remaining tracks are re-used to search for further vertices.

The fitter is implemented in the package RecoVertex/TrimmedKalmanVertexFinder

Usage

A default An easy way to use the TKVF is through the KalmanTrimmedVertexFinder. It uses a conventional Kalman filter to fit the vertices, without the user having to specify anything. It is then used like any other VertexReconstructor.
KalmanTrimmedVertexFinder finder;
vector<TransientVertex> vertices = finder.vertices ( vector<TransientTrack> tracks );

Parameters

The following parameters can be defined by the following set methods:

  • ptCut: defines the minimum pT of the tracks used to make vertices.
    default: 1.5 GeV/c
    method: setPtCut(float cut)
  • trackCompatibilityCut: defines the probability below which a track is considered incompatible with the 1st vertex candidate formed.
    default: 0.05
    method: setTrackCompatibilityCut(float cut)
  • trackCompatibilityToSV : defines the probability below which a track is considered incompatible with the next vertex candidates formed.
    default: 0.01
    method: setTrackCompatibilityToSV(float cut)
  • vertexFitProbabilityCut: defines the probability below which a vertex is rejected
    default: 0.01
    method: setVertexFitProbabilityCut(float cut)
  • maxNbOfVertices : defines the maximum number of vertices searched for. 0 means no limitations.
    default: 0
    method: setMaxNbOfVertices(int max)

-- Main.speer - 05 Jul 2007

 
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