The framework candidate: Gaudi

1
The framework candidate Gaudi

• Toby Burnett and Traudl Hansl-Kozanecki
• GLAST telecon
• 27 January 2000

2
What is a framework?

• And why do we need it?
• Answer an execution environment that provides
• Services
• Messages
• Parameters
• Transient data storage
• Persistent/transient conversion
• Support for a processing model
• Flexible way to sequence processing steps
• Steps (algorithms) should be independent
• e.g., TKR and CAL reconstruction do not know
  about each other
• Why dont we just write it?

3
Because some clever folks at CERN have done itwe
think.

• Called Gaudi (name of a Barcelona architect
  1852-1926)
• Good
• Well-designed (general belief)
• Addresses all the same needs as we have
• Uses the package concept as defined by CMT
• Much documentation (pdt links)
• Original design document (94 pages)
• Current manual (156 pages)
• Relatively stable
• Some one else wrote it, supports it
• Implemented as a dll
• Not-so-good
• We didnt write it
• It is for a different experiment LHCb-specific
  parts
• Support is not really for us, and 6-9 hours time
  difference
• No linux shareables yet

4
Proposal we study it until 1 March

• Download it and install in
• Windows2000/Visual Studio (Toby)
• Linux/Sniff (Traudl)
• Others?
• Talk to LHCb people (Toby at CHEP2000, Traudl at
  CERN)
• Build test programs using GLAST code
• Develop our own build/run configuration
• Get experience with
• Basic ideas (like interfaces and Algorithms)
• Services we know we want (Parameters, Data,
  Messages)
• Give feedback to Gaudi people for mods (and
  perhaps contribute)
• But what if there is a show-stopper? ?square zero
• If not, take 8 more weeks to finish adapting for
  GLAST.
• ? Release date 1 June

5
Technical details interface

• What is an interface? Here is a the Gaudi main
  program, missing only includes and error-checking

void main() IInterface iface
GaudicreateApplicationMgr()
SmartIFltIPropertygt propMgr(IID_Iproperty,
iface) SmartIFltIAppMgrUIgt appMgr
(IID_IAppMgrUI, iface) propMgr-gtsetProperty(St
ringProperty(JobOptionsPath, jobOptions.txt)
appMgr-gtrun()

• The object returned by GaudicreateApplicationMgr
  implements (at least) two interfaces Iproperty
  and IAppMgrUI.

6
Technical details cont. algorithm

• Takes input data, manipulates it, produces output
  data
• Implements the interfaces
• Ialgorithm initialize(), execute(), finalize()
• IProperty
• Services that it (may) require
• Event data
• Detector (geometry) data
• Message
• Histogram
• Summarized by the following diagram

7
Algorithm Framework
8
Structure (p 17 from manual)
9
Proposed GLAST usage of Gaudi
Application
Gaudiframework
RIO
Algorithms
RootCnv(convertors)
CLHEP
Instrument(detect. model)
GlastEvent(event model)
Gaudi
10
Summary

• Looks very promising as a solution to our
  requirements
• Definition of the Event data model, and geometry
  description will proceed independently (neither
  very dependent on a framework)
• Root IO will be used in any case.
• Comments, suggestions, even help will be
  appreciated