"RuntimeError: Negative discriminant in time marcher quadratic." in 2019.1.30, but not in 0.0.9

[Wolfram Moebius]

Hi,

I was running some old code on a new install of scikit-fmm (2019.1.30) and got the following error:

"RuntimeError: Negative discriminant in time marcher quadratic." I don't get the error when running the same code with scikit-fmm 0.0.9.

Looking through the version history, this is of course due to the change in commit 5a1e1db326c91343b09f19b5fc57a4b1b086fb8d, i.e., after release of 0.0.9. I am now trying to understand:

* What does this mean for the results I generated with scikit-fmm 0.0.9. Can I trust them?

* Why do I get the error in 2019.1.30? Shouldn't it be caught in line 85 of travel_time_marcher.cpp?

Thanks,

Wolfram

[Jason Furtney]

Hi Wolfram,

Good to hear from you and I hope you are well in the COVID-19 era. My advice is to use the code from current trunk from Github. In September 2020, a series of nice patches came in that addressed the underlying issue. (I need to get a release out soon.) Without a detailed look, I am not sure if there would be problems with results from 0.0.9. My intuition tells me the differences should be small, but it is worth checking.

Thanks,

Jason