Custom Acts

For similar reasons as Geant4, some developers may want to try building ldmx-sw with a different version of Acts than what resides within the current image. Luckily, using a custom Acts is a bit simpler than Geant4 since there aren't as many pieces of data to consider (for example, Acts does not inspect environment variables for runtime configuration to my knowledge).

Building Your Acts

Remember

You can only run this custom build of Acts with whatever image you are building it with, so make sure you are happy with the image version you are using.

cd path/to/ldmx # directory that contains ldmx-sw
git clone git@github.com:acts-project/acts.git
# checkout specific version or branch
denv cmake -B acts/build -S acts \
  -DCMAKE_INSTALL_PREFIX=acts/install \
  -DCMAKE_CXX_STANDARD=20
denv cmake --build acts/build --target install

The cmake options written above can be experimented with. We use the C++20 standard in ldmx-sw currently, so it is helpful to use the same standard in Acts. The CMAKE_INSTALL_PREFIX is the path where Acts will be installed and that path will need to be inside a directory that is mounted to the container at runtime and provided to ldmx-sw when configuring the build.

Running with Your Acts

Since there aren't other environment variables needed for Acts to function at runtime, we just need to build ldmx-sw with specific cmake options pointing it to our new location of Acts.

just configure -DActs_DIR=/path/to/ldmx/acts/install
just build