ds() failing to converge on estimate?

[Ariek Norford]

I am running the ds() function about 1000 times as part of a simulation study. It works fine for many of the simulated datasets, however, I have noticed that occasionally it gets stuck (stays like this for > 10 hours and then R crashes) at this point: 

Fitting half-normal key function
AIC= 331.062
Fitting half-normal key function with cosine(2) adjustments
AIC= 333.062

Half-normal key function selected.

Is it failing to converge? If so is there a way to have it stop if there is no convergence?

Here is my ds function for context: ds(data = data, key = c("hn","hr","unif"), adjustment =  c("cos","herm","poly"), region_table = region_table, sample_table = sample_table, obs_table = obs_table, initial_values = NULL)

[Eric Rexstad]

Ariek

Your diagnosis is probably correct that convergence failures are causing your problems. Here are a few suggestions

• streamline your candidate model set; no need to have all possible combinations of key functions and adjustment terms
• use the "try-catch" method to trap code failures in loops. Tiago Marques demonstrates the use of this https://github.com/TiagoAMarques/Showcase_tryCatch
• consider using the distance sampling simulation package dsims. It is designed to be robust to convergence failures. https://cran.r-project.org/web/packages/dsims/index.html

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From: 'Ariek Norford' via distance-sampling <distance...@googlegroups.com>
Sent: 03 August 2025 18:52
To: distance-sampling <distance...@googlegroups.com>
Subject: [distance-sampling] ds() failing to converge on estimate?

 

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[Ariek Norford]

Thank you for these suggestions! I was able to get my code running.