Design and performance evaluations of generic programming techniques in a R&D prototype of Geant4 physics

Abstract

A R&D project has been recently launched to investigate Geant4 architectural design in view of addressing new experimental issues in HEP and other related physics disciplines. In the context of this project the use of generic programming techniques besides the conventional object oriented is investigated. Software design features and preliminary results from a new prototype implementation of Geant4 electromagnetic physics are illustrated. Performance evaluations are presented. Issues related to quality assurance in Geant4 physics modelling are discussed.

Photon Elastic Scattering Simulation: Validation and Improvements to Geant4

“…Two policies have been defined for the simulation of photon elastic scattering, corresponding to the calculation of total cross section and to the generation of the scattered photon; they conform to the prototype design described in [54], [55]. A photon elastic scattering process, derived from the G4VDiscreteProcess class of Geant4 kernel, acts as a host class for these policy classes.…”

Refactoring, reengineering and evolution: paths to Geant4 uncertainty quantification and performance improvement

“…The last two features are associated with an inadequate problem domain analysis: refactoring techniques are not sufficient to deal with these deficiencies, which require improving the problem domain decomposition to provide sound foundation for the software design. A prototype design that addresses these issues, deriving from more effective problem domain analysis, was presented at a previous conference [15]; this design approach, which exploits generic programming techniques, has been adopted in a recent large scale study of photon elastic scattering simulation [12], where it demonstrated its ability to support the development of a large variety of physics models and has enabled in-depth verification and validation of their capabilities.…”

Ionization Cross Sections for Low Energy Electron Transport

“…Preliminary evaluations [32], [33] indicate that policy-based design contributes to achieve better computational performance than conventional inheritance in the calculation of cross sections, thanks to compile-time binding. This feature is relevant to the computationally intensive domain of Monte Carlo particle transport, especially at low energies, where discrete transport methods, involving a large number of steps and accounting for individual collisions with the interacting medium, may be required for precise calculation.…”

“…The developed cross section classes can be used in association with the Geant4 toolkit for the simulation of electron ionization as a discrete process, through the mechanism of a policy host class as described in [15], [32], [33]. The BEB and DM cross section code can also be exploited for the creation of data libraries to be used in the current Geant4 scheme, thus extending Geant4 simulation capabilities below the current 250 eV limit recommended for the use of the EEDL library.…”