Fix the way pars is supplied to single resonator formulas

[SebastienJoly]

📝 Pull Request Summary

For a single resonator, the helper function get_impedance() uses:

impedance_data = imp.Resonator_longitudinal_imp(
    frequency_data, pars, wakelength
) 

However, it is not called the same way as the n resonators variant imp.n_Resonator_longitudinal_imp()
The individual Rs, Q, and f_resonant are passed instead of a pars array.

🔧 Changes Made

Thankfully, it can easily be fixed by using a starred expression, see:

impedance_data = imp.Resonator_longitudinal_imp(
    frequency_data, *pars, wakelength
) 

✅ Checklist

• Code follows the project's style and guidelines
• [] Added tests for new functionality
• [] Updated documentation (mentioned in docs/ or included in examples/ and notebooks/)
• Verified that changes do not break existing functionality (automatic tests passing)

📌 Related Issues / PRs

[github-actions]

🧪 Coverage Report

Name                                 Stmts   Miss  Cover
--------------------------------------------------------
iddefix/__init__.py                      7      0   100%
iddefix/_version.py                      1      0   100%
iddefix/framework.py                   345    156    55%
iddefix/objectiveFunctions.py           37     16    57%
iddefix/resonatorFormulas.py           202    142    30%
iddefix/smartBoundDetermination.py     103     14    86%
iddefix/solvers.py                      93     30    68%
iddefix/uncertainties.py                28      0   100%
iddefix/utils.py                       108     45    58%
--------------------------------------------------------
TOTAL                                  924    403    56%

Updated: 2026-07-01T13:30:51.025Z