Many tools are available for the simulation of ILC detectors and the analysis of results. There are three differents toolchains that can be used, corresponding to the LDC, SiD, and GLD detectors. The software suites corresponding to the first two detectors can simulate all 3 detector concepts, so there is no strict division on which tools should be used for a certain detector study.
The ALCPG and SLAC use the SLIC Simulations Package (C++) with the org.lcsim for reconstruction and analysis using Java. This system also uses the JAS3 graphical analysis environment. Much of the functionality within org.lcsim comes from the FreeHep Java Library.
There is a C++ framework developed under ECFA that uses Mokka for the simulator with the MARLIN tool for analysis and reconstruction.
Finally, the ACFA group has a suite of softare based on the ROOT framework.
The LCSim Software Index has links to all the primary tools for ILC Detector Simulations. The Portals Section lists sites that cover full suites of software.
SLIC is the recommended simulator because it allows great flexibility and power in the specification of the detector geometry. LCDD provides a 100% runtime description of the detector and its associated properties, including the detailed volume hierarchy, assignment and properties of sensitive detectors, and the specification of detector component identifiers, among many other features. In practice, writing files in this standardized format is much easier than trying to author custom C++ code for each proposed full detector design and their subdetectors.
The org.lcsim package is recommended, because it uses the Java programming language, which is generally much easier to get started with and use than C++, especially for those with only partial time to devote to ILC research. Additionally, JAS3 provides a number of integrated tools such as the WIRED event display and an AIDA-compliant plotter.
The remainder of this FAQ focuses (almost exclusively) on the US/ALCPG/SLAC software suite based on SLIC and org.lcsim. The LCIO file format and its different language implementations ensure a basic level of interoperability between the three disparate systems should you want to "mix and match". |
The linearcollider.org forum is an appropriate place to post your questions on detector simulations and reconstruction and analysis.
The SLAC Jira Bugtracker allows users to submit bug reports or make feature requests.
The projects relavent to ILC are ...
Each package will be covered in more detail within this FAQ.
Several packages are used by org.lcsim that are not specific to ILC simulations. There is a separate FreeHep bugtracker for these projects. These Jira projects include ...
Contact Tony Johnson <tony_johnson@slac.stanford.edu> to obtain an account on either of these systems.
SLIC stands for "Simulator for the Linear Collider". It is a full simulation package that uses the Geant4 Monte Carlo toolkit to simulate the passage of particles through the detector. SLIC outputs LCIO files that can be analysed using a variety of language bindings, including Java, C++, FORTRAN, and Python. SLIC uses a separate backend for the input of detector data called Linear Collider Detector Description (LCDD), which itself is based on the GDML project from CERN.
The SLIC Confluence page is the best source for up-to-date information on this software package.
Jeremy McCormick <jeremym@slac.stanford.edu> is the primary author and maintainer of SLIC. The handling of MCParticles in SLIC was based on earlier work by Ron Cassell <cassell@slac.stanford.edu> from a package called Linear Collider Simulator (LCS). Much work has also been done by Ron to verify and debug the LCIO output files.
Fermilab: Here are instructions for Fermilab users on getting started with SLIC.
SLAC: Here are instructions for SLAC users on running slic from the public Unix machines at the lab. SLIC can be used on any of the load-balanced interactive Linux clusters, including noric, iris, and yakut.
NICADD: A copy of SLIC is available on the NICADD Linux clusters at /k2data/APPS/SimDist.
These are known working configurations of platform and compiler.
platform |
compiler |
compiler version |
---|---|---|
Linux |
g++ |
3.3, 3.4 |
OSX |
g++ |
4.0 |
Windows (Cygwin) |
g++ |
3.4 |
The only supported compiler is g++. Other versions may work, but these are the ones that are known to build successfully.
SimDist downloads contain binaries for Linux, OSX, and Windows.
These are located at ...
http://www.lcsim.org/dist/slic/ |
To download a Linux release, use these commands.
wget http://www.lcsim.org/dist/slic/slic-1_13_3-Linux-g%2B%2B-bin.tar.gz tar -zxvf slic-1_13_3-Linux-g++-bin.tar.gz |
The SimDist package bundles together all the dependencies of SLIC into one project. This greatly simplifies the build process.
SimDist has a run script at scripts/slic.sh which will setup the LD_LIBRARY_PATH to contain the Xerces lib directory and execute the current slic binary from the packages/slic/[slic_version] directory.
It is useable from anywhere on the host where it was installed.
/path/to/my/SimDist/scripts/slic.sh [options] |
This script passes all arguments to slic, so use it as you would the normal binary.
Follow the build instructions for the SimDist project to make binaries for your platform.
Building SLIC and its dependencies "from scratch" is not encouraged now that the SimDist project can manage this build procedure.
There are separate instructions for building on Linux and building on Windws if you must do this.
If you installed SLIC in the recommended way, the only runtime dependency would be the Xerces C++ shared library. The Xerces library directory needs to be added to the LD_LIBRARY_PATH (bash), so that the loader can find this library when slic executes.
export LD_LIBRARY_PATH=/path/to/my/xerces/install/lib:$LD_LIBRARY_PATH |
If you see this error, it means that the LD_LIBRARY_PATH has not been set correctly.
./slic/bin/Linux-g++/slic: error while loading shared libraries: libxerces-c.so.27: cannot open shared object file: No such file or directory |
The SimDist run script will set this variable automatically.
Assuming you are within the slic package's top directory you would run it with this command.
./bin/$G4SYSTEM/slic [options] |
The G4SYSTEM variable depends on your platform. For instance, on Linux, it is set to Linux-g++, so the command would be ...
./bin/Linux-g++/slic [options] |
To see explanations of slic's command-line options, use the "-h" option.
slic -h |
This will print slic usage and exit.
The command
slic -v |
prints the SLIC version, along with a lot of other information (probably too much).
SLIC prints a splash screen as it starts up with the version, build date, and other information.
************************************************************* App : Simulator for the Linear Collider (SLIC) Version : v1r13p6 Date : Tue Apr 4 17:32:07 PDT 2006 Authors : Jeremy McCormick and Ron Cassell Inst : SLAC WWW : http://www.lcsim.org/software/slic Contact : jeremym@slac.stanford.edu ************************************************************* |
The Geant4 toolkit prints a splash screen that SLIC displays when it starts up.
************************************************************* Geant4 version Name: geant4-08-00-patch-01 (10-February-2006) Copyright : Geant4 Collaboration Reference : NIM A 506 (2003), 250-303 WWW : http://cern.ch/geant4 ************************************************************* |
The Geant4 version in the figure above is 8.0.p01.
SLIC commands are added into various directories within the Geant4 UI hierarchy. From interactive mode, use this command to print information on a SLIC or LCDD command.
help [command] |
Those directories containing only SLIC or LCDD commands are marked with SLIC or LCDD.
/lcio/ LCIO output commands. [SLIC] |
Type
help [dir] |
or
help [command] |
for information about the user interface directory or command. Of course, this requires that the programmer actually put in some useful help string. Most commands and directories have such information.
You can put Geant4 UI commands into one or more macro files that slic can execute. This is done with the "-m" switch. There can be any number of these switches given to slic at the commandline. For instance, this command will execute the two macros init.mac and run.mac.
slic -m init.mac -m run.mac |
The macros are executed in the order given at the command-line.
If macros are interspersed throughout the command switches, then SLIC will also execute each command in order.
slic -m init.mac -x -o output -p myDir -m run.mac |
First init.mac will be executed. Then the three commands corresonding to the "-xop" switches and finally run.mac presumably executes the /run/beamOn command.
SLIC can be started in interactive mode using the -n option or the /control/interactive UI command.
This command will start Geant4 in PreInit mode where the geometry is not loaded.
slic -n |
Other commands may also be executed before the interactive mode starts.
slic -g myGeom.lcdd -n |
The LCDD file will be constructed, so the simulator will start in Idle mode.
The following command illustrates some of the options that could be used in a typical batch run.
slic -g myGeom.lcdd \ # geometry file -i events.stdhep \ # StdHep input file -p lcio/ \ # path for LCIO output file -o output.slcio \ # name of LCIO output file -x \ # delete existing LCIO file -r 1234 \ # seed the random engine -s 100 \ # number of events to skip -r 1000 # number of events to run |
In bash, direct all output to a file, as follows.
slic &> job.log & |
Now use the tail command to look at the output file as the job progresses.
tail -f job.log |
The BeginEvent and EndEvent markers are the best indicators of the job's progress.
Most batch systems will provide logging services, and the tail command can be used on these files, too.
The bsub command is used to run SLIC on LSF.
No.
Because getting things to run on the Grid is hard.
The LCDD system supports reading both plain GDML and LCDD files from SLIC.
To read in a "plain" GDML file, simply use the "-g" option as you normally would ...
slic -g myGeom.gdml |
The LCDD system will use the GDML schema instead of LCDD and the geometry should be loaded successfully.
Compact detectors are kept at this base url in zip files.
http://www.lcsim.org/detectors |
For instance, this is the location of the sid00 zip file.
http://www.lcsim.org/detectors/sid00.zip |
The org.lcsim conditions system will use this URL automatically. Otherwise, a tool like wget can be used to download it manually.
A list of available compact detectors is kept at this URL.
http://www.lcsim.org/detectors/taglist.txt |
LCPhys is used by all three of the main ILC simulation packages, SLIC, Mokka, and JUPITER.