[memalign]

You might be interested in this graphing calculator I made using interval arithmetic:

https://memalign.github.io/m/formulagraph/index.html

Some detail on how this works, including links to the relevant interval math code:

https://memalign.github.io/p/formulagraph.html

[0xml]

Looks like GrafEq?

http://www.peda.com/grafeq/