License & Acknowledgements

License

FORGE is released under the GNU Lesser General Public License v3.0 (LGPL-3.0-or-later).

A copy of the license is included in the repository as LICENSE.

FreeGS Attribution

Several modules in FORGE are derived from or inspired by FreeGS, an open-source Grad-Shafranov equilibrium solver also released under LGPL-3.0.

The following modules contain code originally authored by the FreeGS contributors (primarily Ben Dudson, University of York):

forge.greens — the Greens function is based on the equivalent in gradshafranov.py from FreeGS; all other functions are original to FORGE.
forge.magnets — Coil, ShapedCoil, Solenoid and Circuit classes are based on the FreeGS equivalents.
forge.quadrature — quadrature rules based on the FreeGS quadrature module, modified for FORGE.
forge.critical — critical-point finding routines based on critical.py from FreeGS, modified for FORGE.
forge.machine — inspired by the Machine class in FreeGS, but substantially rewritten for FORGE.

Each of these files retains the original FreeGS copyright notice alongside the FORGE copyright, as required by the LGPL.

Bundled Data

FORGE ships with MAST-U coil and wall geometry data for use in the examples and tests. These data are derived from open-source data published by UKAEA and are licensed separately from the FORGE source code:

License: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
Citation: Harrison, J. (2026). MAST-U freegs coil configuration (Version 1.0) [Data set]. UKAEA. https://doi.org/10.14468/JMPP-4C57

The NonCommercial clause means this data may not be used for commercial purposes. The data is provided for example and testing purposes only and is not required for FORGE to function — users may substitute their own machine data. A full copyright notice is included alongside the data files at src/forge/data/json/MAST-U/MAST-U_UKAEA_open_data_copyright_notice.txt.

Note

The MAST-U machine configuration represented by the bundled data corresponds to the MAST-U device as operated during the period 2020–2025. Any subsequent modifications to the machine are not reflected in these data.

Authors and Contributors

Chris Marsden — Project lead and primary developer.
Sebastien Shaw — Summer student who developed the foundational prototype during his FOSTER placement (2025).
Nathan Welch — SCOPE project lead, whose guidance on simulated annealing underpins the optimisation approach.
Ben Dudson & FreeGS contributors — Original authors of the modules from which FORGE borrows.

GUI Framework

The FORGE GUI is built with Panel and Bokeh.

The documentation and GUI sidebar reproduce a small number of toolbar-tool icons ( ) originally shipped with Bokeh, which is released under the BSD 3-Clause licence. These icons are redistributed here under the terms of that licence.