General usage

The installation guide for the library and general examples may be found here.

Several tools are shipped to ease the user interaction with the library. All of these can be compiled (after the CMake environment is set as described here) through a simple make <tool_name>. The associated output executable may then be found in your build/ directory. Conventionally, a make install command can be run, either as administrator to install these system-wise, or locally by overriding the CMAKE_INSTALL_PREFIX environment variable.

For instance, one may find the following:

• cepgen (see here) is the main CepGen executable. It allows computing the process cross section and launching an events generation. According to the steering card content, the events may or may not be stored on disk after production. For instance, in the LPAIR process Python steering card, the event content is printed on screen by the dump module every 10’000 generations.

  A few extra arguments can be passed through the command line. As for other utilitaries, these are generally documented adding the -h, or --help flag after the command name. Beside this “help” flag a few additional “standard” flags are handled, i.e.

  • -d or --debug turns on the verbose mode, and produces a lot of useful debugging information

  • -v or --version shows the compiled CepGen version tag and returns.

  For the cepgen executable, one also finds:

  • -i or --config allows to provide the input steering card path,

  • -n or --num-events lets the user override the number of events to be generated,

  • -o or --output allows to define a comma-separated list of output modules names to which events shall be fed (with standard parameters values)

  In addition, two useful flags are:

  • -s or --safe-mode, to disable the loading in the runtime environment of all add-ons found, either in the build directory, or in the CEPGEN_PATH. Useful in the case where a package under its experimental phase is corrupted.

  • -a or --add-ons, to specify a comma-separated list of shared libraries to load at the runtime. For instance in combination to the earlier, it allows to spot precisely which package is inducing an error, or to load new processes generated and pre-compiled externally.

  Finally, the -l or --list-modules flag allows to dump a list of modules (output, event modification, drawing, functional parser, …) accessible in the runtime environment after the loading of the various shared libraries.

• cepgenDescribeModules gives a user-readable description of one, or all modules defined in the runtime environment. The -a, or --all flag produces a complete list of all modules, similar to the one given in this raw list.

We suggest you to use CepGen through the main executable, in combination with the various steering modules available. These are, to explicitely name a few,

• Python, structured configurations

• LPAIR-like steering cards

• JSON, XML, INFO-formatted configurations, as handled by the Boost.PropertyTree serialisation library (requires CepGenBoost to be loaded).

We can however assist you in producing a packaged version, fitting to your event generation scheme. Please fill in an issue or contact us for more details.