LCIO A persistency framework for LC detector simulation studies

1
LCIO A persistency framework for LC detector
simulation studies

• Frank Gaede, DESY, IT
• Linear Collider Simulation Workshop SLAC May
  19-22 2003

2
People

• Ties Behnke - DESY/SLAC
• Frank Gaede - DESY
• Norman Graf - SLAC
• Tony Johnson - SLAC
• Paulo Mora de Freitas - IN2P3

3
Outline

• Introduction
• Software design
• API
• Data model
• Status
• Summary

4
Motivation
Java, C, Fortran
Java, C, Fortran Geant3, Geant4
Java, C, Fortran
geometry
5
The Persistency Framework
LCIO
data model
contents
6
LCIO requirements

• need Java, C and f77 (!) implementation
• extendable data model for current and future
  simulation studies
• user code separated from concrete data format
• -gt need to be flexible for future decisions on
  persistency
• three general use cases
• writing data (simulation)
• reading and updating data (reconstruction)
• read only access to data (analysis)
• needed a.s.a.p. -gt keep it simple !

7
API design simulation data

• Interface for
• writing data (simulation)
• read only access (analysis)

tagging interface
untyped collections
user extensions
data entities
8
API implementation
abstract event
abstract io
concrete classes
persistency implementation
9
Extending the base API
minimal interface needed for writing data
decorator classes add convenient methods to data
objects
10
API definition for Java and C

• use AID Abstract Interface Definition
• tool from freehep.org (M. Dönzelsmann)
• used successfully in the AIDA project
• define interfaces in Java-like language with C
  extensions
• -gt generates files with Java interfaces
• -gt generates C header files with pure abstract
  base classes
• use javadoc for documentation
• independent implementations in Java and C
• -gt keep Java pure i.e. machine independent

11
AID example
12
API documentation
API documentation created from java
implementation with javadoc
13
C developer documentation
documentation created from C
implementation with doxygen
14
Example reading data

• LCReader lcReader
• LCFactorygetInstance()-gtcreateLCReader(
  )
• lcReader-gtopen( "myFile" )
• LCEvent myEvt
• while( ( myEvt lcReader-gtreadNextEvent() ) !
  0 )
• cout ltlt " Evt " ltlt myEvt-gtgetEventNumber(
  )
• ltlt " - " ltlt myEvt-gtgetRunNumber()
• ltlt " " ltlt myEvt-gtgetDetectorNa
  me()
• ltlt endl
• cout ltlt endl
• lcReader-gtclose()

independent of persistency implementation !
15
Example reading event collections

• LCEvent evt
• while( ( evt lcReader-gtreadNextEvent() ) ! 0
  )
• const LCCollection col evt-gtgetCollection(
  EcalHits)
• int nHits col-gtgetNumberOfElements()
• for( int i0 ilt nHits i )
• const CalorimeterHit hit
• dynamic_castltconst CalorimeterHitgt
• 
  ( col-gtgetElementAt( i ) )
• const float x hit-gtgetPosition()
• cout ltlt x " ltlt x0 ltlt ", " ltlt x1 ltlt ",
  " ltlt x2
• ltlt " energy " ltlt
  hit-gtgetEnergy() ltlt endl

untyped collections addressed via name
16
LCReader API

• direct access via fast skip
• read next event/run
• callbacks for modules

17
Example writing data (events)

• LCWriter lcWrt LCFactorygetInstance()-gtcreat
  eLCWriter()
• lcWriter-gtopen( "myFile" )
• for( int i0 iltNEVENT i )
• LCEventImpl evt new LCEventImpl()
• evt-gtsetRunNumber( rn )
• evt-gtsetEventNumber( i )
• // add collections ...
• lcWrt-gtwriteEvent( evt )
• delete evt // C only )
• lcWriter-gtclose()

use LCIO implementation classes or own classes
for writing !
18
Example writing collections

• LCCollectionVec trkVec
• new LCCollectionVec(
  LCIOTRACKERHIT )
• for(int j0jltNHITSj)
• TrackerHitImpl hit new TrackerHitImpl
• hit-gtsetdEdx( 30e-9 )
• double pos3 1., 2., 3.
• hit-gtsetPosition( pos )
• trkVec-gtpush_back( hit )
• evt-gtaddCollection( (LCCollection) trkVec ,
  TPCHits )
• // write event

19
LCWriter API
20
LCIO Fortran interface

• Fortran support for
• legacy software (e.g. BRAHMS reconstruction)
• non OO-analyses code (old guys)
• not a third implementation of the library use
  C-wrapper functions and cfortran.h instead
• one function for every class member function
• use integers to store pointers !
• have factory and delete functions
• -gt OO-like code in fortran

21
LCIO f77 example
22
Persistency Implementation

• use SIO Simple Input Output
• developed at SLAC for NLC simulation
• already used in hep.lcd framework
• features
• on the fly data compression
• some OO capabilities, e.g. pointers
• C and Java implementation available

23
The Data Model - Overview
RunHeader
Event
ReconstructedObject
SimHeader
ReconstructedParticle
MCParticle
RecoHeader
Reco
SIM
TrackerHit
Track
CalorimeterHit
Cluster
for details see transperencies after summary
24
Status of LCIO

• first Java and C implementation (simulation
  data!)
• integrated into Mokka simulation framework
• latest release mokka-01-05 writes Hits in
  LCIO
• f77 prototype
• demonstrating the design
• complete integration into simulation software
  chains in the next months
• US hep.lcd (Java) ? -gt to be discussed at
  this workshop
• Europe Mokka (C)/BRAHMS-reco(f77)

25
Summary

• LCIO is a persistency framework for linear
  collider simulation software
• Java, C and f77 user interface
• LCIO is currently implemented in simulation
  frameworks
• hep.lcd
• Mokka/BRAHMS-reco
• -gt other groups are invited to join
• see LCIO homepage for more details
• http//www-it.desy.de/physics/projects/simsoft/lci
  o/index.html

26
Data model - LCRunHeader

• block RunHeader
• int runNumber
• string detectorName
• string description
• string activeSubdetectors
• gt describes the run setup

27
Data model - LCEventHeader

• EventHeader
• int runNumber
• int evtNumber
• string detectorName
• String subdetectorName
• blockNames
• string blockName
• string blockType

28
Data model LCEvent (sim)

• MCParticle
• pntr parent
• pntr secondparent
• pntr daughters
• int pdgid
• int hepevtStatus
• (0,1,2,3 HepEvt)
• (201, 202 sim. decay)

• MCParticle cont.
• double3 start
• (production vertex)
• float3 momentum
• (at vertex)
• float energy
• float charge

29
Data model - LCEvent (sim)

• TrackerHit
• string subdetector
• int hitFlags (detector specific Id, key, etc.)
• double3 position
• float dEdx
• float time
• pntr MCParticle

30
Data model - LCEvent (sim)

• CalorimeterHit
• string subdetector
• int cellId0
• int cellId1
• float energy
• float3 position optional (file size!)
• particle contributions
• pntr MCParticle
• float energyContribution
• float time
• int PDG (of secondary) - optional

31
Data model - LCEvent (reco)

• OutputHeader
• int isrFlag
• float colliderEnergy
• int flag0 (to be defined)
• int flag1 (to be defined)
• int reconstructionProgramTag
• float Bfield
• -gt could be combined with global header

32
Data model - LCEvent (reco)

• Track
• int tracktype (full reconstr, TPC only, Muon
  only, etc.)
• float momentum
• float theta
• float phi
• float charge
• float d0 (Impact Parameter in r-phi)
• float z0 (Impact Parameter in r-z)
• float15 cov.matrix
• float reference point (x, y, z)
• float chi2 of fit
• float10 dEdx (weights and probabilities)
• TrackerHits - optional
• pntr TrackerHit

33
Data model - LCEvent (reco)

• Cluster
• int detector (type of cluster ECAL, HCAL,
  combined)
• int clustertype (neutral, charged, undefined
  cluster)
• float energy
• float3 position (center of cluster x, y, z)
• float6 errpos (cov. matrix of position)
• float theta (intrinsic direction theta at
  position)
• float phi (intrinsic direction phi at position)
• float3 errdir (cov. matrix of direction)
• float6 shapeParameters (definition needed)
• float3 weights (compatible with em., had.,
  muon)
• CalorimeterHits - optional
• pntr CalorimeterHit
• float contribution

34
Data model - LCEvent (reco)

• ReconstructedParticle
• int primaryFlag (0 secondary, 1 primary)
• int ObjectType (charged/ neutral particle)
• float3 3-Vec (px, py, pz)
• float energy
• float10 covariance matrix
• float charge
• float3 reference position for 4-vector
• float5 PID_type (hypotheses for e, g, pi, K,
  p, ...)

• ReconstructedParticle cont.
• Tracks
• pntr Track
• floatweight
• Clusters
• pntr Cluster
• floatweight
• MCParticles
• pntr MCParticle
• floatweight

have separate MC-link object ?
35
Data model - LCEvent (reco)

• ReconstructedObject
• int ObjectType (jet, vertex, ... )
• float5 4vec (4-vector of object (px, py, pz,
  E, M)
• float3 reference (position)
• float15 covariance matrix
• reconstructedParticle
• pntr ReconstructedParticle
• float weight
• gt generic reconstructed objects, linked to
  reconstructed particles