Align sine fit comparison fixture

[chenzc24]

Summary

• Fix the sine-fit comparison test to use the actual MATLAB reference folder name, run_sinfit.
• Add the missing run_sinfit MATLAB reference outputs for sinewave_noise_200uV.
• Make the Python integration fixture use MATLAB sinfit's refinement budget explicitly (max_iterations=100, tolerance=1e-12) while leaving the public fit_sine_4param defaults unchanged.

Rationale

This is a compare-fixture/policy alignment, not a core sine-fit algorithm change. MATLAB run_sinfit.m calls sinfit(read_data), whose default niter is 100 and tol is 1e-12. Python's public default intentionally remains lighter (max_iterations=1), but the MATLAB parity fixture should exercise the same refinement budget as MATLAB.

The previous compare test looked for test_sinfit, while the MATLAB runner and run_all_comparisons.py use run_sinfit, so the comparison failed before reaching numeric parity.

Experiment

Dataset: reference_dataset/sinewave_noise_200uV.csv

Default Python fixture vs MATLAB reference:

• freq max abs diff: 2.30204744156e-13
• mag max abs diff: 4.28363233773e-10
• dc max abs diff: 1.9206858326e-14
• phi max abs diff: 2.93023383335e-10
• data_fit max abs diff: 4.76205318234e-10
• convergence: False, n_iterations=1, emits RuntimeWarning

MATLAB-compatible fixture (max_iterations=100, tolerance=1e-12) vs MATLAB reference:

• freq max abs diff: 2.4302782009e-13
• mag max abs diff: 2.22044604925e-16
• dc max abs diff: 9.99200722163e-16
• phi max abs diff: 8.4354745411e-13
• data_fit max abs diff: 7.06010805374e-11
• convergence: True, n_iterations=2, no warning

Tests

• uv run --with pytest pytest tests/integration/test_sine_fit.py -q --artifact-root E:/.tmp_artifacts/sinfit-refinement-policy
• uv run --with pytest pytest tests/compare/test_compare_sine_fit.py -q --comparison-output-root E:/.tmp_artifacts/sinfit-refinement-policy/test_output
• uv run --with pytest pytest tests/unit/fundamentals/test_verify_fit_sine_4param.py -q
• uv run --with pytest pytest tests/unit/aout/test_error_fit_options.py -q
• git diff --check