InnerDetector / MuonSpectrometer shared reconstruction code

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InnerDetector / MuonSpectrometer shared
reconstruction code

• 4 packages common to iPatRec, Moore and
  MuonIdentification (combined reconstruction)
• 2 packages contain families of data classes
• iPatTrackParameters (4 classes)
• iPatTrack (8 classes - plus some legacy classes)
• 2 algorithmic packages
• iPatTrajectory (5 classes) swim TrackParameters
  through Atlas magnetic fields (choice of
  parametrisation or RungeKutta integration)
• iPatTrackFitter produce FitQuality and fitted
  TrackParameters at various positions along the
  track trajectory

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iPatTrackParameters

• TrackParameters
• base class containing position, direction,
  momentum and charge
• functions provide related (derived) quantities
  such as HepVector3D direction or double theta,
  eta, cos_theta, cot_theta etc
• PerigeeParameters
• inherits from TrackParameters
• at closest approach to Vertex
• adds impact parameter, covariance (HepSymMatrix)
• ScattererParameters
• inherits from TrackParameters
• at intersect with scattering plane
• adds scattering angles, covariance (HepSymMatrix)

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iPatTrack design features

• Polymorphic behaviour represented by aggregation
• enumerated Status describes different kinds of
  hit or track
• strip-cluster, broad-cluster, drift-hit,
  drift-wire, scatterer, dead, hole, inert
• primary, truncated, secondary, muon,
  combined-muon
• client distinguishes differences
• Track and TrackEnvelope classes
• flexible design requirement - basically sets of
  pointers to detailed data classes
• bool query (has) methods allow for lightweight
  (partial) implementation
• early pattern recognition phase, trigger, fast
  simulation
• TrackEnvelope
• contains fill and set methods for detailed data
  classes
• Track ownership passed on request results in
  internal data clear
• Track
• const access to data classes
• primitive predecessor to StoreGate lock mechanism

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iPatTrack package

• HitOnTrack
• HitStatus (strip-cluster, drift-hit, material
  types)
• link to digit, cluster
• track-dependent calibration of measurement
  position (global coords) and weighting (local)
• all required geometrical information for track
  fitting (wire/strip orientation, radiation
  thickness and energy loss)
• fit residuals for alignment
• Track
• TrackStatus (primary, muon )
• vector ltTrackParametersgt
• list ltHitOnTrackgt
• HitQuality
• FitQuality
• implementation of requirements collected during
  1998/9

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part of Track data class family(as presented
during May 2000 s/w week)
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Additional requirements

• collection/container
• selection - make available according to status,
  ROI, vertex association, quality or parameter
  criteria
• sort criteria (by momentum, angle, status etc)
• persistency
• currently independent of StoreGate (as also used
  by atrecon)
• need ADL description (? to Srini)
• HitOnTrack represents 80 of data volume
• needed for alignment, event display and track
  refitting (with improved calibration)
• but not for physics analysis
• evolution
• transform to physics coord system (solenoid
  rotated wrt beam axis)
• private TrackParameter data as 4-momenta - more
  appropriate for physics analysis