Simulation Review

• Outline
  • Simulation Code Road Map
  • Simulation Code Inventory
  • Plans

• Cast of Characters
  • P.B.Armstrong
  • J.R.Bogart
  • G.R.Bower
  • R.Cassell
  • R.Dubois
  • D.L.Flath
  • A.S.Johnson
  • A.P.Waite

PPT Slide

LCD Road Map

fastMC (JAS)

JAS analysis

Gismo

Full Recon

Root parser

JAS parser

fastMC (Root)

JAS parser

Root parser

Generator(s)

Simulation Code Inventory (SLAC)

Key

l Fully implemented

l Fully implemented (including PIC)

l In progress

l Not attempted

l Twinkle in our eye!

Gismo

• Still working with a copy taken over a year ago. The GLAST and LCD versions have diverged (architecturally at least) since then!

• Our improvements/modifications
  • Remove generation truncation limit
  • Fix assorted PDG errors
    • u,d quarks swapped
    • Higgs renumbered from 9999 to 25
    • Correct some B baryon masses
  • Remove miscalculated looping limit (essential for background overlay)

• Outstanding
  • Fix NaN problem in optimized Linux code (EGCS 1.1 compiler?)
  • Fix debug problem in optimized DEC/OSF1 code (EGCS 1.0.3 compiler?)

GismoApps

• Fixes/improvements incorporated
  • Add a VXD cryostat
  • Fix calorimeter layer encoding to avoid overflows
  • Add north/south encoding for tracking hits
  • Add a version number to the ASCII output file

• Fixes/improvements still required
  • Realistic magnetic field maps

• All GismoApps code now stored/controlled by CVS

• GismoApps being used as a test-bed for
  • Development Environment Controller (DEC) testing
  • XML testing
  • Serial Input/Output (SIO) testing

Root and RootApps

• Joanne Bogart working on introducing XML

• ‘Keepers of the Flame’ are Masako Iwasaki and Homer Neal

• Homer has Root/RootApps running on a DEC/OSF1 platform

• Please see Masako’s talk for further details

Geant and GeantApps

• Version 4.0.1 of Geant was released 19 July 1999

• Dependence on commercial software
  • No longer dependent on RogueWave (good)
  • Only persistence model fully supported is Objectivity (unfortunate but not fatal)

• Dependence on free software
  • CLHEP
  • A variety of visualization schemes
  • Cygnus Solutions ‘Cygwin’ environment (Windows/NT only)

• Trying to persuade SCS to support Geant centrally

• No LCD applications written yet!

CLHEP (for Gismo) and CLHEP

• Class Library for High Energy Physics (CERN product)

• Three versions exist at SLAC
  • CLHEP for Gismo as LCD took it over a year ago
  • CLHEP for Gismo as used by GLAST today
  • CERN’s official version

• LCD Gismo/GismoApps still uses the first version

• Geant requires the official version

stdHEP

• Fermilab product

• Used almost exclusively in LCD to read and write generator files

• Out of the box, it does not support
  • PIC libraries (needed by Root)
  • Windows/NT (LCD/SLAC has hacked together its own version)

XML and XMLApps

• We use many independent ASCII input files to Gismo, fastMC (JAS), fastMC (Root), etc. despite the fact that they often contain overlapping information.

• This style of ASCII input tends to be inflexible (to the extent that most of these programs have hard wired some constants rather than change the ASCII file format).

• XML provides a method to build an in-memory database of constants based on one or more flexibly defined ASCII input files.

• XML is becoming a standard.

• XMLApps is an application level library being written by Joanne Bogart to provide access to XML generated database(s).

• Joanne Bogart is predicting a week’s work to complete a single platform Gismo/GismoApps application running with XML/XMLApps (2/3 done already). Unfortunately the week doesn’t start until she returns from vacation.

SIO (Serial Input/Output)

• What XML does for ASCII input files, SIO attempts to do for ASCII output data files

• ASCII output data files tend to be
  • Bulky
  • Information Lossy
  • Inflexible

• SIO addresses these problems by providing
  • A binary format (industry standard xdr format)
  • A counted, self navigating layout
  • Multiple I/O streams each allowing heterogeneous record types
  • Enforced data versioning

• Tony Johnson is currently trying to read an SIO file generated from a Gismo/GismoApps application

• Could provide a solution for Geant persistency

Short Term Plan (ɞ months)

• Distribute! (~week(s))
  • Take the results of this meeting to create new detectors
  • Incorporate all the technical fixes we know about
  • Construct the simulation executables (Gismo but not Geant)
  • Test
  • Distribute code to collaborators

• Farm! (~month(s))

• • Transmit the output files to Penn.

• Tradeoffs
  • Incorporate SIO? (probably). XML? (probably not). Realistic field maps? (probably not).
  • How much testing?

Long Term Plan (> 6 months)

• What we are targeting
  • Adopt Geant (to replace Gismo)
  • Carry forward our GismoApps code to GeantApps
  • If XML didn’t make it into the Gismo round, adopt it now
  • If SIO didn’t make it into the Gismo round, adopt it now (or come up with another solution to the Geant persistency problem)
  • Incorporate realistic magnetic field maps

• Open questions
  • Geant persistency model
  • {your question here}