How to start using the ACTS framework

The Acts (A Common Tracking Software) framework is an open-source project designed for track reconstruction and simulation in particle physics experiments. This guide explains how to set up a local working environment on the Stoomboot cluster and run the included Python examples, following the Acts 'getting started' page with minor adjustments.

Setup:

• On the Stoomboot cluster, start by navigating to your user account directory. /data/alice/<username>

• Next, activate a compatible LCG (LHC Computing Grid) software environment. LCG provides a pre-packaged set of libraries and compilers. For the Acts framework, a view containing GCC 13 or later is required for C++20 compatibility. A working example: source /cvmfs/sft.cern.ch/lcg/views/LCG_108/x86_64-el9-gcc13-opt/setup.sh This command must be executed in every new shell session.

• Clone the Acts repository from GitHub to your local machine. Replace `<source>` with your desired directory name. git clone https://github.com/acts-project/acts <source>

• Navigate into the cloned repository and configure the build with cmake. To enable the Python bindings for the examples, you must explicitly pass the corresponding flags. cd <source> cmake -B build -S . -DACTS_BUILD_EXAMPLES=ON -DACTS_BUILD_EXAMPLES_PYTHON_BINDINGS=ON -DPYBIND11_USE_FETCHCONTENT=ON

• Next, compile the project. cmake --build build

Run Examples:

• Before running the Python scripts, you must run the setup.sh script to configure your environment. This script modifies your PYTHONPATH, an environment variable that tells Python where to look for modules. source build/python/setup.sh This command must be executed in every new shell session.
• Once your environment is set up, you can execute any of the Python example scripts. The files are located in the Examples/Scripts/Python directory. For example, to run the particle propagation script, use the following command: python Examples/Scripts/Python/propagation.py

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