UFO Model Loader

UFO Model Loader is a Python CLI and library to work with High-Energy Physics models in the UFO format.
It can:

• Load UFO models or pre-exported JSON models
• Apply restrictions from parameter cards
• Evaluate all dependent parameters from input parameters using Symbolica
• Simplify couplings and disable zero contributions
• Preserve propagating/Goldstone flags, custom propagators, declared functions, and form-factor metadata
• Export the result as a flat JSON model

Limitations:

• Only tree-level information is being retained and exported
• Current version only supports export of model expression in the Symbolica notation

Installation

From PyPI:

pip install ufo-model-loader

From GitHub:

pip install "git+https://github.com/alphal00p/ufo_model_loader.git"

Command Line Usage

ufo_model_loader --help

Example:

ufo_model_loader -i sm -r no_b_mass -o sm_flat.json

This will:

1. Load the default UFO sm model shipped with this python module
2. Apply restrictions from restrict_no_b_mass.dat
3. Simplify the model by removing zero contributions and parameters set to zero.
4. Write the model sm_flat.json and its corresponding parameter card sm_flat_param_card.json to the current directory.

Library Usage

When using UFO Model Loader as a library, you can import the main functions:

from ufo_model_loader.commands import load_model, export_model, JSONLook

loaded_sm_no_b_mass, input_param_card_no_b_mass = load_model(
    input_model_path = 'sm',
    restriction_name = 'no_b_mass',
    simplify_model = True,
)

exported_model_path = export_model(
    model = loaded_sm_no_b_mass,
    input_param_card = input_param_card_no_b_mass,
    output_model_path = 'sm_no_b_mass_simplified_flat.json'),
    json_look = JSONLook.VERBOSE,
    allow_overwrite = True
)

Built-in models

UFO Model Loader comes with the following built-in models: sm and scalars, which can be specified as input model directly from their names (the corresponding UFO directories are shipped with the python package).

The scalars model is a purely scalar toy model, with a number of scalars controlled by the environment variable UFO_SCALARS_MODEL_N_SCALARS, and all possible n-point interactions mixing these scalars, with n given by the environment variable UFO_SCALARS_MODEL_N_POINT_INTERACTIONS. By default, UFO_SCALARS_MODEL_N_SCALARS="3" and UFO_SCALARS_MODEL_N_POINT_INTERACTIONS="3,4,5,6,7,8,9,10".

For example, the following:

UFO_SCALARS_MODEL_N_SCALARS=7 UFO_SCALARS_MODEL_N_POINT_INTERACTIONS="3,4,5,6,7,8" ufo_model_loader -j compact -i scalars -o scalars_big_model.json; du -hc scalars_big_model.json

yields a pretty big model :)

[23:34:27] INFO    : Loading UFO model scalars from directory '[...]/ufo_model_loader/src/ufo_model_loader/data/models'
Loading UFO scalars model with 7 scalars
Loading UFO scalars model with n-point interactions, n=[3|4|5|6|7|8]
[23:34:28] INFO    : Applying default restriction to model scalars
[23:34:28] INFO    : The following 6 external parameters were forced to zero by the restriction card:
width_scalar_1, width_scalar_2, width_scalar_3, width_scalar_4, width_scalar_5, width_scalar_6
[23:34:28] INFO    : Model scalars successfully loaded (7 particles, 20 parameters, 6399 interactions, 1 couplings, 6 Lorentz structures)
[23:34:28] INFO    : Successfully exported model in compact JSON format to file 'scalars_big_model.json' and corresponding input parameter card to 'scalars_big_model_param_card.json'
1.5M	scalars_big_model.json
1.5M	total

Tests

Test your installation with

pytest --pyargs ufo_model_loader_tests

Main options

• --input_model, -i
  UFO directory or JSON file path to load.

• --restriction_name, -r
  Restriction to apply (restrict_<restriction_name>.dat in UFO or restrict_<restriction_name>.json beside a JSON model). Without this option, restrict_default.dat or restrict_default.json is applied when present. Legacy <model>_default.json cards remain accepted.

• --simplify / --no-simplify
  Remove zero contributions in the model given specified restriction. Default: enabled.

• --wrap_indices_in_lorentz_structures Wrap indices in Lorentz structures when exporting. This is particularly useful for spin-2 models, mapping <1 or 2>00<p_id> conventions to idx(1 or 2, p_id). Default: disabled.

• --output_model_path, -o
  Output path for the JSON model. Defaults to current directory.

• --json_look, -j
  Output format: compact, pretty, or verbose. Default: verbose. Note: pretty requires the optional python package jsbeautifier.

• --verbosity, -v
  Logging level: debug, info, critical.

• --overwrite, -w
  Allow overwriting existing output files.

Development

Clone the repo and install in editable mode:

git clone https://github.com/alphal00p/ufo_model_loader.git
cd ufo_model_loader
pip install -e .[dev]
pytest