Here is a belated reply to your comment about the python-cf library.[0] My top-level comment[1] does not present its use cases well. While you can compute the billionth digit of π with continued fractions, other methods suit this task better. The library caters to those who need much fewer significant digits. Such users can rely on the result undisturbed by numerical errors, as illustrated by the iterated logistic map in my slides[2].

Happy New Year! :)

[0] https://news.ycombinator.com/item?id=25266072 [1] https://news.ycombinator.com/item?id=25263435 [2] https://marcinciura.files.wordpress.com/2019/10/cf-slides.pd...