source_residuals crashes with ValueError: x and y arrays must be equal in length after BH inversion on noisy stations

[wangzb0329]

Hi @claudio-satriano

First of all, thank you so much for developing SourceSpec. It's a brilliant tool and has been central to my research on regional earthquakes!

I'm currently running into an issue during the source_residuals step and would love to get your advice to see if I am doing something wrong, or if this is an expected edge case.

After running a batch of events (Mw 4.0 - 5.5) using the Basin-hopping (BH) algorithm, I try to compute the mean station residuals. However, the process consistently crashes on one specific noisy station (CQ.CQT) with this SciPy error:
Python

Processing station: CQ.CQT.00.BHH
Traceback (most recent call last):
...
File "sourcespec/source_residuals.py", line 270, in compute_mean_residuals
spec_interp.interp_data_to_new_freq(freq_array)
File "sourcespec/spectrum.py", line 130, in _interpolate_data_to_new_freq
f = interp1d(freq, data, fill_value=fill_value, bounds_error=False)
File "scipy/interpolate/_polyint.py", line 128, in _set_yi
raise ValueError("x and y arrays must be equal in length along interpolation axis.")
ValueError: x and y arrays must be equal in length along interpolation axis.

To figure out what was happening, I did some testing:

I noticed that CQ.CQT has very poor high-frequency SNR. During the initial source_spec run, the BH algorithm often struggles to fit it.

Even though the inversion fails for this station, it seems a record is still written into the [eventid].residuals.hdf5 file.

My guess is that during this failed attempt, the frequency array (x) and the residual array (y) somehow ended up with different lengths (maybe due to NaN values?). When source_residuals tries to interpolate them, it crashes.

Is my understanding of this crash correct?

Is using ignore_stations the recommended way to handle such noisy stations that break the interpolation? Or is there a parameter I should tune to prevent these mismatched arrays from being written in the first place?

Thank you so much for your time and guidance!

Best regards,