The αLoop code is currently distributed as plugin of the Madgraph5_aMC@NLO (MG5aMC) code.
The first installation step is therefore to install MG5aMC by downloading the latest target on the download page and untar it in a directory, later refered to as <MG_ROOT>.
You can then clone the github repository in the PLUGIN directory of MG5aMC, i.e.
cd <MG_ROOT>/PLUGIN
git clone https://github.com/alphal00p/alphaloop
For convenience, it also then useful to link the customised αLoop UFO SM model in the <MG_ROOT>\models directory of MG5aMC:
cd <MG_ROOT>/models
ln -s ../PLUGIN/alphaloop/models/aL_sm .
Then, you should install all Python dependencies with:
cd <MG_ROOT>/PLUGIN/alpha_loop
python -m pip install -r requirements.txt
(Note: the gvar and vegas packages installation wheels can be broken and may require a manual installation from source), as well as additional dependencies later used by rust, using:
cd <MG_ROOT>/PLUGIN/alpha_loop
bash deploy.sh
The compilation of the rust backend engine is achieve with:
cd <MG_ROOT>/PLUGIN/alpha_loop/rust_backend
cargo build --release
Finally, if you intend to use the Python bindings of αLoop, you should also compile the corresponding library with:
cd <MG_ROOT>/PLUGIN/alpha_loop
./make_lib release
which will generate the file ltd.so which can be loaded from within Python with import ltd,
see Python.
You should now be ready to run your first example of the computation of the NLO cross-section for the process , see epem_a_ddx_NLO.