Acts Common Tracking Software

or A Common Tracking Software if you do not like recursive acronyms

Acts is an experiment-independent toolkit for (charged) particle track reconstruction in (high energy) physics experiments implemented in modern C++.

More information can be found in the Acts documentation.

Quick start

Acts is developed in C++ and is build using CMake. Building the core library requires a C++17 compatible compiler, Boost, and Eigen. The following commands will clone the repository, configure, and build the core library

git clone https://github.com/acts-project/acts <source-dir>
cmake -B <build-dir> -S <source-dir>
cmake --build <build-dir>

For more details, e.g. specific versions and additional dependencies, have a look at the getting started guide. If you find a bug, have a feature request, or want to contribute to Acts, have a look at the contribution guidelines.

Versioning and public API

Release versions follow semantic versioning to indicate whether a new version contains breaking changes within the public API. Currently, only a limited part of the visible API is considered the public API and subject to the semantic versioning rules. The details are outlined in the versioning and public API documentation.

Repository organization

The repository contains all code of the Acts projects, not just the core library that a physics experiment is expected to use as part of its reconstruction code. All optional components are disabled by default. Please see the getting started guide on how-to enable them.

• Core/ contains the core library that provides functionality in the Acts namespace.
• Plugins/ contains plugins for core functionality that requires additional external packages. The functionality also resides in the Acts namespace.
• Fatras/ provides fast track simulation tools based on the core library. This is not part of the core functionality and thus resides in the separate ActsFatras namespace.
• Examples/ contains simulation and reconstruction examples. These are internal tools for manual full-chain development and tests and reside in the ActsExamples namespace.
• Tests/ contains automated unit tests, integration tests, and (micro-)benchmarks.
• thirdparty/ contains external dependencies that are usually not available through the system package manager.

Authors and license

Contributors to the Acts project are listed in the AUTHORS file.

The Acts project is published under the terms of the Mozilla Public License, v. 2.0. A copy of the license can be found in the LICENSE file or at http://mozilla.org/MPL/2.0/ .

The Acts project contains copies of the following external packages:

• dfelibs by Moritz Kiehn licensed under the MIT license.
• JSON for Modern C++ by Niels Lohmann licensed under the MIT License.