ACTS Tutorial for ALICE 3 studies

Instructions how to run the full chain simulation and reconstruction.

Full ACTS documentation is located here.

ACTS lxplus installation:

lrnvmbp14@macbookpro ~ % ssh [your username]@lxplus.cern.ch
[plariono@lxplus986 plariono]$ cd /afs/cern.ch/work/[your username]
[plariono@lxplus986 plariono]$ mkdir actsdir && cd actsdir
[plariono@lxplus986 actsdir]$ git clone git@github.com:acts-project/acts.git source && cd source

Then the dependencies can be satisfied via an LCG release in the following way: source /cvmfs/sft.cern.ch/lcg/views/<lcg_release>/<lcg_platform>/setup.sh

[plariono@lxplus986 actsdir]$ source /cvmfs/sft.cern.ch/lcg/views/LCG_107/x86_64-el9-gcc13-opt/setup.sh
[plariono@lxplus986 actsdir]$ mkdir acts
[plariono@lxplus986 actsdir]$ cmake -S source -B acts -DACTS_BUILD_PLUGIN_GEANT4=on -DACTS_BUILD_PLUGIN_ROOT=on -DACTS_BUILD_FATRAS=on -DACTS_BUILD_FATRAS_GEANT4=on -DACTS_BUILD_EXAMPLES_GEANT4=on -DACTS_BUILD_EXAMPLES_PYTHON_BINDINGS=on -DACTS_BUILD_ANALYSIS_APPS=on -DACTS_BUILD_EXAMPLES_PYTHIA8=on
[plariono@lxplus986 actsdir]$ cmake -—build acts -j$nproc

ACTS aliBuild installation:

aliBuild init
git clone git@github.com:AliceO2Group/acts.git
aliBuild -d build ACTS

Fixing potential issues with the aliBuild installation (M. Faggin)

Issue: ImportError: libHepMC3.so.4: cannot open shared object file: No such file or directory

Fix: export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:"/path-to-HepMC3/3.3.0-44/lib"

Issue: Missing or not found Boost package

Fix: Install Boost or edit the $PATH: export PATH=$PATH:"/path-to-boost/v1.83.0-alice2-local1/include"

When the installation is completed you can pull the tutorial repository and place it in actsdir.

Material maps:

The material-map is provided in .zip format. The full-chain job will unzip it automatically at the first run.

IRIS 4 geometry

https://cernbox.cern.ch/s/IcBXKkxEgaxvyLt

After that the file must be placed in actsdir/tutorial_acts_june25/geom/iris4.

Geometry version Oct24, IRIS pure cylindrical

https://cernbox.cern.ch/s/PpjPUjx1F3HACFC

After that the file must be placed in actsdir/tutorial_acts_june25/geom/geom_oct24.

Running the full chain simulation and reconstruction on lxplus

cd tutorial_acts_june25
source setup.sh
source ../source/CI/setup_cvmfs_lcg.sh
source ../acts/python/setup.sh
python3 full_chain_alice3_tutorial.py --usePythia -n1000

The output files will be located in actsdir/reco_output_pythia.

Get the $\it{p}_{\rm{T}}$ resolution plot

Located in tutorial_acts_june25, run:

root -l -q 'getPtResolution.C+g("reco_output_pythia")'

This will create the folders Plots and treeoutput in reco_output_pythia which contain the figure and the ROOT with the $\it{p}_{\rm{T}}$ resolution.

Get the reconstruction efficiency

The reconstruction efficiency histogram can be found in reco_output_pythia/performance_finding_ambi.root as a TEfficiency object: trackeff_vs_pT, trackeff_vs_eta, trackeff_vs_phi.

The binning can be changed my modifying source/Examples/Framework/src/Validation/EffPlotTool.cpp.