Temporarily use Euler-derived location instead of NonlinearMagneticDipoleBz location estimates#121
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YagoMCastro merged 1 commit intomainfrom Oct 17, 2025
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This PR restores the use of source locations estimated by `NonlinearMagneticDipoleBz`, replacing the temporary use of Euler Deconvolution results. The inversion algorithm was corrected to fix the inaccurate location estimates previously produced. After the fix, `NonlinearMagneticDipoleBz` now provides accurate and consistent positions, better than those from Euler Deconvolution. This update affects the `iterative_nonlinear_inversion` function, which implements the full methodology presented by [Souza-Junior (2025)](https://eartharxiv.org/repository/view/8869/). In our implementation, the original Nelder–Mead–based inversion from the paper is replaced by a more robust Levenberg–Marquardt–based inversion **Changes made** - **Set a lower limit to `r²`** to avoid excessively large derivatives when source–data distances become very small. - **Construct the damping matrix proportional to the diagonal of the Hessian**, ensuring that regularization adapts to parameter sensitivity. - **Reduce the global scaling factor** to stabilize updates and prevent overshooting during optimization. Together, these changes make the inversion more robust against numerical instabilities and improve convergence consistency across different datasets. **Relevant issues/PRs:** #121 #120 #107
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This PR temporarily replaces the source location estimated by the
NonlinearMagneticDipoleBzinversion with the one obtained from Euler Deconvolution.Recent tests show that the Euler-derived locations produce more accurate and consistent results, while the positions estimated by
NonlinearMagneticDipoleBzsometimes exhibit instability or unrealistic values.This suggests there may be a bug in the nonlinear inversion algorithm.