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Units PowerPoint Presentation

Units

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Units

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  1. Units David R. Quarrie Lawrence Berkeley National Laboratory DRQuarrie@LBL.Gov

  2. Background • Geant3 • cm & GeV • Herwig • mm & GeV (& secs) • Pythia • mm & GeV • Isajet • GeV (zero lifetimes) • Hijing • fm & Gev David R. Quarrie: Units

  3. Baseline Proposal • Adopt CLHEP/Geant4/HepMC units • mm & MeV • ATLAS put this before the developer/physicist community • Physics community strongly prefer use of GeV for LHC • Deferring any migration until a LCG-wide decision • Wish to make it in next months David R. Quarrie: Units

  4. Suggestions (1) • Accept CLHEP units but use scaling macros #include “CLHEP/Units/SystemOfUnits.h” Length = 2.0 * mm • Possibility of dangerous side-effects • Install ATLAS-specific version of CLHEP • Install ATLAS-specific scaling macros #include “ATLAS/Units/SystemOfUnits.h” Length = 2.0 * atmm David R. Quarrie: Units

  5. Suggestions (2) • Use FNAL ZOOM SI Units package • http://www.fnal.gov/docs/working-groups/fpcltf/Pkg/SIunits/doc/0SIunits.html • Supports several models, including mm+GeV • Typesafe#include "SIunits/stdModel.h" using namespace si;Length len2( 4.1 * foot );Mass mass( 2.0 * GeV ); • Don’t know who’s using it, or level of support David R. Quarrie: Units