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How much sacrifice are we talking about here?

@mcara , are you satisfied with this fix?

For once, the benchmark results might be related.

| Change   | Before [7c77a0f3]    | After [060118be]    |   Ratio | Benchmark (Parameter)                                   |
|----------|----------------------|---------------------|---------|---------------------------------------------------------|
| +        | 4.20±0.3ms           | 5.91±0.3ms          |    1.41 | modeling.fitting.time_combined_gauss_1d_LevMarLSQFitter |

SOME BENCHMARKS HAVE CHANGED SIGNIFICANTLY.
PERFORMANCE DECREASED.

@mcara , are you satisfied with this fix?

@pllim I think this solves the issue of backward compatibility.

I think we're waiting for Tom's comment at #16982 (comment) to be resolved.

?

@mcara , are you satisfied with this fix?

@pllim I think this solves the issue of backward compatibility.

Sigh... not really. My bad: I should have run full tests. I didn't notice the change of fitparam_indices. This breaks old code.

https://github.com/spacetelescope/tweakwcs/actions/runs/11073910939/job/30771524455?pr=212#step:10:193

=========================== short test summary info ============================
FAILED tweakwcs/tests/test_linearfit.py::test_levmar2x2_multivariate - TypeError: _LevMarLSQFitter2x2.objective_function() got an unexpected keyword argument 'fit_param_indices'

I fixed the issue on my side so again this is not of importance for me (I think...).

Thanks for reporting back, @mcara . I opened #17085 follow-up issue that blocks v7.0 release until it is resolved.