Global rcParams change on import

[OnDraganov]

In persim/landscapes/visuals.py, line 15 defines mpl.rcParams["text.usetex"] = True. This means that whenever we import persim, the behavior of pyplot changes to that setting in all the pyplot uses. This is undesirable, as the user might prefer the default pyplot options for other uses than calls through persim.

If TeX rendering is necessary for the plots, is it possible to do the change only locally whenever a plot is created? It could be done using with mpl.rc_context({"text.usetex": True}): construction or by passing usetex=True at the individual places where it is desired.

[catanzaromj]

Thanks for the issue @OnDraganov. Absolutely! I agree that this shouldn't be set as a global. I believe we only use TeX for subscripts and superscripts in a mathematician friendly way. I think the context manager mpl.rc_context is a great way to deal with this. Are you interested in submitting a PR to implement the change?

[maximelucas]

I've just encountered the same problem.

If TeX is only used for subscripts and superscripts, it might not be necessary at all?
Default math rendering by matplotlib does this already. In that case, I would remove the line entirely and let the user choose to turn TeX if they want to (I'm happy to submit a PR for that).

Unless you use specific characters with which it may not work?

[catanzaromj]

@maximelucas The layers of the landscapes (indexed over depth) are typically denoted with $\lambda$, but I don't think we need latex for that. I think we can just use unicode characters, as shown in the updated answer here. If you agree, then please submit a PR implementing that change.

[OnDraganov]

I tried and r$\lambda_{2}$ actually shows correctly even with matplotlib.rcParams['text.usetex'] being False (matplotlib version 3.8.4). So just erasing the 15 should be enough. Is that worth a pull request?

[maximelucas]

Yes most of the time it works even without the "r" in front.
I just created a PR.