1. LAT Instrument Operations Center
Overview of GLAST Offline software - a fusion of Particle- and AstroPhysics Worlds
Richard Dubois, Stanford Linear Accelerator Center
for the GLAST Science Analysis Software Group
GLAST is a next generation high-energy gamma-ray observatory designed for making observations of celestial gamma-ray sources in the energy band extending from 10 MeV to more than 100 GeV, with launch anticipated in Its primary scientific objectives are to understand the mechanisms of particle acceleration in AGNs, pulsars and supernova; determine the high-energy behavior of gamma-ray bursts and probe for dark matter. The Science Analysis Software group is responsible for creating the software that will process the data, starting from receipt from the Mission Operations Center through to analyzing photon lists and creating source catalogues.
We will provide an overview, describing the planned data flow from space through reconstruction and analysis, including key components of our ground software system. We will cover our HEP-like event reconstruction (uniquely focused on pair-conversion), simulation tools and our interface with the astronomy world which supplies astro-standard tools for high level analysis. We will describe the infrastructure that makes it possible for our small but very dispersed development team (distributed across 9 time zones) to work together, including our code development and build systems, and the data servers that deliver instrument and photon data to our users. Finally we will describe the Data Challenges, beam tests and engineering models that are being used to ensure readiness of the software.
Instrument Simulation and Reconstruction
CAL Detail
Instrument
data
3 GeV gamma interaction
3 GeV gamma recon
Full geometry in xml with C++ interface
G4 discovers instrument from the xml
France Germany Italy Japan Sweden USA
Package
Description
Provider
Status
ACD, CAL, TKR Recon
Data reconstruction
LAT
In use
ACD, CAL, TKR Sim
Instrument sim
GEANT4
Particle transport sim
G4 worldwide collaboration
xml
Parameters
World standard
Root
C++ object I/O
HEP standard
Gaudi
Code skeleton
CERN standard
doxygen
Code doc tool
Visual C++/gnu
Development envs
World standards
CMT
Code mgmt tool
ViewCvs
cvs web viewer
cvs
File version mgmt
Data flow in the Gaudi framework
Transient Data Store
Ntuple
Level 1
Simulation Algorithms
Level 0
Reconstruction Algorithms
Ntuple Service
Pseudo Persistency Algorithms G4
ACD, TKR, CAL
Digitization Algorithms
Source
Generators
Root
ACD, TKR, CAL,
Trigger
Raw data
Ready for astronomy MC
Real Data
~25 software contributors
Instant messaging:
Example of Using Gaudi Tools
   IEnergyCorr* m_lastLayerTool;
   sc = toolSvc()->retrieveTool(m_lastLayerToolName, m_lastLayerTool);
 m_lastLayerTool->setTrackSlope(slope);
 m_lastLayerTool->doEnergyCorr((*it)->getEnergySum(),(*it));
Retrieve tool by name via base class
Refer to base class functions. Does not know which concrete tool it is.
Concrete classes that customize behaviour
Tools id’ed by name in ascii config file (“jobOptions”)
Gaim-icq
Almost all meetings via
Web conferencing: vrvs
Code Development gui
Clean, config, make, debug
Run apps
Tabbed ouput buffers
cvs operations
Package tree
Fox/Ruby app
Flight Operations GN
HEASARC
GSFC -
DELTA
7920H •
White Sands
TDRSS SN
S & Ku
LAT Instrument Operations Center
GBM Instrument
Operations Center
GRB
Coordinates Network
Telemetry 1 kbps S
Alerts
Data, Command Loads
Schedules
Archive
Mission Operations
Center (MOC)
GLAST Science
Support Center
GLAST Spacecraft
Large Area Telescope
& GBM
GPS
GLAST MISSION ELEMENTS
TLM: 1,2,4,8 kbps
Science 40 Mbs (13 GB/day average)
CMD: .25, 4 kbps
Internet 2
40 Mbs
R.Dubois
Java
Tied in to Release Manager builds database
Provide self-contained scripts to run executables sans CMT
Multiple views
3D controls
Graphics tree
Graphics metadata:
HepRep
Event control
GLAST plugin
GlastRelease config
Fox/Ruby/C++ app
Collaboration Support
Integration Data
One code system for all uses:
Simulations, Engineering Models,
Beam Tests, Flight Operations
Code Installer
The Simulated DC1 Sky
Extragalactic diffuse
Galactic diffuse
EGRET 3EG
Fiddling 3C273/279
Our Sky
Event Visualization
Automated Code Builds
Past release
Release in progress
Future release
Display created from database query
Performing builds
for Science Tools
also
Build status
Unit test status
V&V: System tests of software builds
Comparison of
current to previous
release.
Three Data Challenges
Web tag collector
All builds done in batch
windows
linux
Multiple packages being tracked
Run by Release Manager
auto triggered
some 800 histos per code build
shapes compared to standards
all tracked in database
See N.Golpayegani poster
Data Challenges
Ground software is amalgam of HEP instrument software and Astro FTOOLS
Adopt HEP’s “Data Challenges” to create a series of end-to-end studies: create a progression of ever more demanding studies
DC1. Modest goals. Contains most essential features of a data challenge.
1 simulated day all-sky survey simulation
find GRBs
recognize simple hardware problem(s)
a few physics surprises
Exercise all the components
DC2, start beginning of CY06. More ambitious goals. Encourage further development, based on lessons from DC1. One simulated month.
DC3, in CY07. Support for flight science production.
DC Components
Focal point for many threads
Orbit, rocking, celestial coordinates, pointing history
Plausible model of the sky
Background rejection and event selection
Instrument Response Functions
Data formats for input to high level tools
First look at major science tools – Likelihood, Observation Simulator
Generation of datasets
Populate and exercise data servers at SSC & LAT
Code distribution on windows and linux
Involve new users from across the collaboration
Teamwork!
Data Analysis for High Energy Astronomy
Framework driven by
Desire for uniformity between missions
Guest observer support (HEASARC)
Aggregate nature of the data: events are (almost) never analyzed individually
Standardized software and data formats
FITS files for images and tabular data
FTOOLs for examining and manipulating contents
Can be mission-specific
User interfaces – “parameter interface layer”, ballistic operation
Often scripted (Tcl, Perl), some GUI use
High level analysis applications: Xspec (from Xanadu suite), Sherpa, ISIS (from CIAO), etc.
Unix-based tradition; GLAST pushing for Windows support