The PERSINT Visualization Program for the ATLAS Experiment D. Pomar

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The PERSINT Visualization Program for the
ATLAS ExperimentD. PomarèdeCEA/DSM/DAPNIA/SEDI
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OUTLINE

• INTRODUCTION
• DESIGN
• GENERAL PRESENTATION
• APPLICATIONS
• VISUALIZATION OF GEOMETRY
• EVENT DISPLAY
• PROSPECTS

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INTRODUCTION

• PERSINT (PERSpectively INTeracting) is designed
  for the three-dimensional representation of
  objects and for the interfacing to a variety of
  applications, in a fully interactive way.
• It has the following features
• 3D representation of objects in full volumes or
  wire frames
• Computation of hidden faces
• Spatial navigation with real-time displacements
• Focal length adjustable at will (from isometry to
  wide-angle)
• Interfaces and access to applications
• Maximum interactivity
• Documentation

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INTRODUCTION

• PERSINT was originally developed as a tool for
  debug-ging and optimizing the ATLAS Muon pattern
  recognition and track reconstruction algorithm
  (MUONBOX)
• PERSINT is now used routinely for
• Visualization of detector geometries
• AMDB (ATLAS Muon DB)
• AGDD-XML (ATLAS Generic Detect. Description)
• Event Display (hits reconstruction objects)
• Complex Monte Carlo Events
• ONLINE EVD in TestBeams
• Other
• Magnetic field, Level-1 Trigger Logic (Muon),

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DESIGN

• Core in F90
• Usage of Modules, with procedure interfaces
• Polymorphism
• Recursive functions
• Dynamic arrays
• Allocate (local memory management)
• Pointers
• String operations
• Array manipulations
• Free source forms

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DESIGN

• GRAPHICS Interface HIGZ
• In general, use of CERNLIBS
• 26000 lines of code
• Part of the Saclay Muon Software suite, and as
  such interfaced directly to
• AMDBSIMREC (geometry database) 13000 lines
• BFIELDDTB (magnetic field database) 3500
  lines
• MUONBOX (track reconstruction) 58000
  lines

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DESIGN

• Highly modular, organized in patches
• e.g. XML section
• Computation of volumes, hidden faces
• based on analytical computation of facets edges
• Highlight intersections, detect clashes
• Boolean operations
• Lighting intensity effects on volume facets
• Designed to operate in standalone mode, keeping
  the possibility of integration in frameworks

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PRESENTATION OF THE PROGRAM

• General layout
• Navigation
• Perspective
• Event Display of complex Monte Carlo events
• Online Event Display
• Interface to AGDD-XML
• Interface to Level-1 Trigger
• Interface to Magnetic Field

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GENERAL LAYOUT
DISPLAY WINDOW
NAVIGATOR
COMMAND WINDOW
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THE NAVIGATOR
SWITCH WIRE/FULL VOLUMES
LEFT CLICK DEFINE MOVEMENTS INVOKE
INTERFACES TO APPLICATIONS
INVOKE INTERFACES
AMDB AGDD-XML EVD
MIDDLE-CLICK GET ONLINE HELP
DISPLACE VIEWER/ VIEWED POINTS
FOCAL LENGTH
PROJECTIVE VIEWS
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NAVIGATION

• Two options
• use the navigator (step-by-step movements)
• real-time continuous displacements

Drag cursor Left button pressed down for
rotation Middle button pressed down for
forward/backward displacements
move up
move left
move right
move in
move out
move down
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FOCAL LENGTH

• Normal view 35 mm

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FOCAL LENGTH

• Infinite F.L. (isometric view)

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FOCAL LENGTH

• Wide angle (few mm F.L.)

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FOCAL LENGTH

• Projections

X-view
Z-view
Also available f-view, Y-view, real-time
lateral displacements
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EVENT DISPLAY OF MONTE CARLO DATA

• Example of event from ATLAS Data Challenge 1,
  single-muon with high lumi pile-up, safety
  factor 5 on cavern component. Interactive track
  reconstruction (MUONBOX).

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EVENT DISPLAY OF MONTE CARLO DATA
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EVENT DISPLAY OF MONTE CARLO DATA

• Example of event from ATLAS Data Challenge 1,
  single-muon with high lumi pile-up, safety
  factor 5 on cavern component. Interactive track
  reconstruction (MUONBOX).

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EVENT DISPLAY OF MONTE CARLO DATA
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ONLINE EVENT DISPLAY

• H8-2002 Muon Testbeam 6 Barrel chambers 5
  Endcap chambers
• Implementation in the online software using the
  Monitoring Factory
• Proved useful in commissioning of detectors and
  understanding of events

PERSINT reads the Event at the SFI level
and displays it
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INTERFACE TO AGDD-XML

• Example description of dead matter (used by
  MUONBOX for M.S.,)
• Display of event hits generic usage (Inner
  Trackers, Calorimeters, )
• Supports all Boolean operations

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BOOLEAN VOLUME OPERATIONS

• PERSINT supports boolean volume ope-rations
• Three basic operations
• Addition
• Subtraction
• Intersection
• This allows the creation of very complex 3D
  objects from simple ones

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INTERFACE TO LEVEL-1 TRIGGER

• Visualization of L1 Trigger objects RoI, PAD
  Logic, Coinci-dence Windows, supervision of
  Coincidence Matrices,
• Example Higgs to four muons event

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INTERFACE TO MAGNETIC FIELD

• Dedicated Interface for

• Visualization of the magnetic field map
• 2D or 3D lattice
• Visualization of magnet elements

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PERFORMANCES

• Navigation with full volumes
• On a 2.8 GHz Pentium 4
• 0.65 sec to compute and display 2300 volumes /
  15000 facets of the Muon precision chambers
  system
• Real-time displacements are fluid (gt 10 views per
  second) for a number of volumes lt 400
• Event Scan on Testbeam Data
• Display events in loop with 6 MDT chambers and
  20 hits
• 0.02 sec/event for bare event display
• 0.20 sec/event with track reconstruction

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AVAILABILITY OF THE CODE

• PERSINT Web Page
• http//cern.ch/Atlas/GROUPS/MUON/persint.html
• AFS Location
• /afs/cern.ch/atlas/offline/external/Persint 
• Documentation updated with every release

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PROSPECTS

• DISCUSSION ON THE DESIGN
• ADVANTAGES
• User can download a single executable binary no
  dll, no fancy APIs to install
• Efficient even if operated remotely (e.g on
  remote clusters from a X-terminal)
• DISADVANTAGES
• Limited graphics interface (256 colors, )
• Does not profit from high performance
  capabilities of graphics cards when operated
  locally on PCs (Z-buffer).

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PROSPECTS

• Planned developments
• Integration in the ATHENA reco/analysis framework
  gt useful to debug events
• Possibility to launch EVD from the ASK
  Interactive toolkit
• Migration to OpenGL ?
• Integrate some parts in ROOT (calculus of hidden
  faces, intersecting volumes, ) ?

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PROSPECTS

• Planned utilization
• Online EVD in the H8-2003 Muon Testbeam
• Online EVD in the H8-2004 Combined Testbeam
• Commissioning of ATLAS participation in the
  debug of the detector (cosmics runs, calibration
  runs, )
• ATLAS Online EVD for monitoring of data-taking