Thanks for the hint to PythonPlot. I did not know this. We will try it.
PyPlot itself does not call OpenMP. Apparently you are calling two different libraries that link two different versions of OpenMP, but I’m not sure what those libraries might be. (They could be two Python packages for all I know.) What else are you using besides PyPlot?
Last week: runtests.jl of Modia3D was working as expected, as long as PyPlot calls were disabled. If PyPlot was called in runtests.jl, for some simulations the problem with OpenMP occured.
Some days ago, I made a new version of Modia with support for GLMakie 0.8 (previously, it was for version 0.6). If I then switched to use PyPlot, everything worked with Modia3D and the error with OpenMP was gone. I don’t understand this, because the GLMakie part is completely unrelated.
Anyway, I am closing this topic, because the problem does no longe occur.