Licensing

probcal is released under the MIT license (see LICENSE).

Conceptual references and GPL code

Several R packages in the calibration literature are GPL-licensed: givitiR (calibration belt), rms, and CalibratR. These are used as conceptual references only: probcal reimplements every algorithm from the primary papers cited in the documentation and never ports, translates, or adapts GPL source code.

Test-only dependencies

scipy, scikit-learn, and statsmodels appear exclusively in the dev extra as numerical references for the test suite. They are never imported by src/probcal (enforced by tests/test_package.py::test_no_forbidden_imports).