III - Computing Infrastructure, Sim and Recon
A - Infrastructure
For the past 10+ years SLAC has been the lead laboratory in the US for linear collider detector R&D computing effort. We have developed tools to allow detailed simulation and reconstruction of detectors. An emphasis of the group has been on developing infrastructure to allow physicists from universities and other labs to rapidly contribute to detector R&D.
There are significant differences in the design of such tools compared to typical experiment specific simulation and reconstruction code.
- The tools must allow easy reconfiguration to support different detector geometries and technologies.
- The tools must make it easy to develop new reconstruction algorithms and plug them in to the existing reconstruction infrastructure.
- The tools must be very easy for users to set up and become productive. Typically physicists working on detector R&D do so with only a fraction of their effort, and often new graduate students or post-docs take over the work after one or two years.
- The tools must work on a wide variety of operating systems. Unlike established collaborations which can require collaborators' computing platforms to meet certain standards detector R&D software must work on whatever computing platforms are available to users.
- The tools must be easy to develop and support using a fraction of the manpower that would be available to an established physics collaboration.
These tools include the SLIC geant4 based simulation program the Java based org.lcsim reconstruction and analysis tools suite, and analysis tools including the WIRED event display and JAS3 data analysis system. <Needs expansion>
These tools were designed to be easy to use and set up so that barrier for users to get involved with the ILC simulation effort were low. For several workshops and conferences in the past we have been able to create CDs containing everything a new user needs to get started with these tools, including install kits, documentation and event samples.
In addition to direct support of these tools the SLAC group has:
- Taken a leading role in the creation and support of LCIO standards to ensure a large degree of interoperability with other efforts in Europe and Asia. The LCIO libraries provide a fully documented standard format for reading and writing events at the generator level, full simulation level, or reconstruction and analysis level. The LCIO libraries support C++, Fortran and Java.
- Made available a large collection of standard simulation samples for a variety of event types and standard detector and accelerator configurations.
- Hosted infrastructure shared with related efforts worldwide the including the
- lcsim.org web site,
- ILC and SiD related content on the confluence wiki(confluence.slac.stanford.edu) including many detailed tutorials and reference documentation.
- Discussion forums at forum.linearcollider.org. These are the primary means of providing support to end users who have questions or problems using the software, as well as for discussion between software developers world-wide.
- CVS repository at cvs.freehep.org and automated continuous build system (hudson). This repository is used to host the LCIO libraries, the core SLIC and org.lcsim software and many user contributed analysis algorithms and tools.