How to run a Geant4 application on the GRID

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How to run a Geant4 application on the GRID

• http//cern.ch/geant4

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Contents

• Requirements
• Software tools
• Geant4 application design
• Geant4 application implementation
• How to run on the GRID

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Requirements

• Same application code for sequential and parallel
  execution
• Transparent execution in sequential/parallel mode
• Transparent execution on a PC farm and on the
  Grid
• Monitor the progress of the simulation execution
• Traceability of failed tasks for debugging
  purposes

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Software tools
Execution in distributed computing
Monte Carlo simulation
Analysis
DIANE
Abstract Interfaces for Data Analysis
www.cern.ch/geant4
www.cern.ch/diane
Physicist Interface (PI)
aida.freehep.org
lcg-pi.web.cern.ch/lcg-pi/
Component-based architecture software tools
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DIANE
http//cern.ch/DIANE
Developed by J. Moscicki, CERN/IT

• RD project
• started in 2001 in CERN/IT with very limited
  resources
• collaboration with Geant4 groups at CERN, INFN,
  ESA
• succesful prototypes running on LSF and EDG

Master-Worker architectural pattern

• Parallel cluster processing
• make fine tuning and customisation easy
• transparently using GRID technology
• application independent

By J. Moscicki (CERN)
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Application design
Generic Geant4 application design

• Transparent execution of the simulation
• In sequential mode
• In parallel mode

Steering the simulation execution in the DIANE
framework
Initialize () ExecuteMacro () Finish () SetSeed()
Encapsulate the essential actions to execute a
simulation
Initialize,
Concrete class derived from IG4Simulation
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Implementation
Example geant4/examples/extended/parallel/ExDiane
Derived from the Brachytherapy advanced example
www.ge.infn.it/geant4/examples/index.html
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Main

• include BrachySimulation.hh
• Int main(int argc, char argv)
• BrachySimulation simulation new
  BrachySimulation(0)
• simulation -gt initialize(argc, argv)
• If (argc gt 1) mn argv1
• simulation -gt executeMacro(mn)
• simulation -gt finish()
• delete simulation
• return 0

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BrachySimulation.cc
BrachySimulation inherits from DIANEIG4Simulatio
n

• BrachySimulationBrachySimulation(G4int seed)
• BrachySimulationBrachySimulation()
• void BrachySimulationsetSeed(G4int sd) // Set
  the seed interactively
• seed sd
• HepRandomsetTheSeed(seed)
• G4bool BrachySimulationinitialize(int, char)
• .
• runManager new G4RunManager
• runManager -gt SetUserInitialization(detectorConstr
  uction)
• runManager -gt SetUserInitialization(physicsList)
• runManager -gt SetUserAction(primaryParticles)
• runManager -gt Initialize()
• void BrachySimulationexecuteMacro(G4String
  fileName) // Execution of the macro file
  

No other code changes
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Execution of a G4 application in a distributed
environment
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Practical Example

• Example simulation with analysis
• The job is divided into tasks
• The tasks are executed on worker components
• Each task produces a file with histograms
• Job result sum of histograms produced by tasks
• Master-worker model
• Client starts a job
• Workers perform tasks
• and produce histograms
• Master integrates the
• results

Start the execution
Result
Result 1
Result n
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Example of a macro

• Application G4Analysis
• WorkerInitData
• G4ApplicationcomponentName G4Brachy
• InitMacroFile
• /control/verbose 1
• /run/verbose 1
• /event/verbose 1
• /run/initialize
• JobInitData
• runParams
• seed 0, // Initial seed
• eventNumber 100000 // Total
  number of events of the job
• macroFileTemplate /run/beamOn
  ,
• eventsPerWorker 10000 // The
  job is subdivided in 10 tasks
• workerInit WorkerInitData

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Distributed computing resources
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Running on the GRID
Master

• DIANE is installed
• Source the environment of DIANE
• cd G4Myapplication
• eval diane.app.setup e csh
• Execute the job
• diane.startjob j macroFileName w workers_at_LCG
• wms LCG_SITES_LIST --ganga

Name of the macro file
Result n
Result 1
Number of workers
List of the sites

• Workers on the GRID
• Geant4, AIDA and PI are preinstalled
• DIANE and G4Brachy are downloaded from the web
• DIANE and G4Brachy are installed
• The tasks are executed

The results of the tasks (analysis objects) are
sent back to the Master
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Example of results
On the Master

• diane.workspace/jobs/ID_job
• Contains the results of the simulation analysis
  objects
• profile.job contains the monitoring of the
  execution of the tasks

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Documentation

• Documentation on DIANE
• http//www.cern.ch/diane
• Installing and compiling DIANE
• Compiling and running a Geant4 application
  through DIANE