Track Seed Validator

Complete: 5

Goal of this page

The SeedValidator is a tool that produces a set of histograms useful to test, validate and debug the track seeds. This page will help the user familiarize with it.

Important note: TrackerSeedValidator has been deprecated in favor (since 8_0_0_pre5) of TrackFromSeedProducer and MultiTrackValidator. (leading to easier maintenance). See SWGuideMultiTrackValidator#cmsDriver_tracking_only_reconstr for more details on how to use that. TrackerSeedValidator will be removed at some point.

SeedValidator and MultiTrackValidator

The SeedValidator is a branch that originates from the MultiTrackValidator. They inherits from the same base class (MultiTrackValidatorBase), where the common functionalities and the common histograms are sored, and they share the same logic. Also the SeedValidator uses View, so the validation plots can be produce using any collection of objects inheriting from the TrajectorySeed class.

Definition of Track Parameters from a Seed

A seed is mainly constituted by a vector of RecHits (two or three) and a TrajectoryState, defined on the surface of the outermost hit. The track parameters (see TackBase.h for more details on the track parameters) are defined at the point of closest approach with respect to the beam line, so the given TrajectoryState is propagated to the point of closest approach using the TrajectoryStateClosestToBeamLineBuilder class, using the same logic that is used in the TrackProducer. The track parameters of the simulated tracks (TrackingParticles) are computed in a coherent way and therefore with the track parameters of the seed.

Where to find it

You can find the SeedValidator in the Validation/RecoTrack package. The default configuration is in Validation/RecoTrack/python/TrackerSeedValidator_cfi.py. A configuration file example to run the SeedValidator is test/TrackerSeedValidator_cfg.py. Check it out from cvs:
cvs co Validation/RecoTrack/test/TrackerSeedValidator_cfg.py

How to run it

The SeedValidator works in the same way as the MultiTrackValidator. The only difference is that the parameter label refers to the module that produced the seeds.

There is an extra parameter, called TTRHBuilder, which defines the component name of the TransientTrackingrecHitBuilder to be used in the SeedValidator. The default values of this parameter is: "WithTrackAngle".

Edit the configuration file as you prefer (you can change the default parameters directly in MultiTrackValidator_cfg.py, for example: process.seedValidator.out = 'myFile.root') and run it, e.g.:

cmsenv
cmsRun Validation/RecoTrack/test/TrackerSeedValidator_cfg.py

The output file

The output file of the SeedValidator works in the same way as the MultiTrackValidator output file. The list of the histograms produced by the SeedValidator is the following:

Validation Plots - Global seeding performances

seeds number of (associated) reconstructed seeds
fakes number of fake reco tracks

effic efficiency vs eta
efficPt efficiency vs pT
fakerate fake rate vs eta
fakeratePt fake rate vs pT
effic_vs_hit efficiency vs number of hits
fakerate_vs_hit fake rate vs number of hits

num_reco_eta Number of seeds vs eta
num_assoc(simToReco)_eta Number of associated seeds (simToReco) vs eta
num_assoc(recoToSim)_eta Number of associated (recoToSim) seeds vs eta
num_simul_eta Number of simulated tracks vs eta
num_reco_pT Number of seeds vs pT
num_assoc(simToReco)_pT Number of associated seeds (simToReco) vs pT
num_assoc(recoToSim)_pT Number of associated (recoToSim) seeds vs pT
num_simul_pT Number of simulated tracks vs pT
nrec_vs_nsim number of reconstructed seeds vs number of simulated tracks (2D plot)

Validation Plots - Number of hits and charge distributions

hits number of hits per seed
hits_eta mean number of hits vs eta
nhits_vs_eta number of hits vs eta (2D plot)

charge charge distribution

Validation Plots - Pulls and residues

eta pseudorapidity residue

pullPt pull of pT
pullTheta pull of theta parameter
pullPhi pull of phi parameter
pullDxy pull of dxy parameter
pullDz pull of dz parameter
pullQoverp pull of qoverp parameter

Seed association plots

assocFraction fraction of shared hits (TrackAssociatorByHits only)
assocSharedHit number of shared hits (TrackAssociatorByHits only)

Plots for cross checking with simulation

ptSIM generated pT
etaSIM generated pseudorapidity
tracksSIM number of simulated tracks
vertposSIM transverse position of sim vertices

Seed Association

The SeedValidator probes the seeding performance by comparing every Seed with the corresponding TrackingParticle. TrajectorySeeds are matched to TrackingParticles using the seed association provided by th TrackAssociatorByHits.

Review status

Reviewer/Editor and Date (copy from screen) Comments
GiuseppeCerati - 29 Apr 2009 Documentation Review

Responsible: GiuseppeCerati
Last reviewed by: Most recent reviewer

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Topic revision: r4 - 2016-05-04 - MattiKortelainen
 
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