nalgebra VS advent-2021

Ok, so this uses https://rapier.rs/ which is very cool

Rapier, alongside https://nalgebra.org/ (which it uses underneath) has seriously good documentation and some advanced features like cross-platform determinism (something made hard by the way floating point differs between platforms)

> Some GA libraries[1][2] define types for the different kind of objects (grades)

That's nice!

This reminds of me things like, linear algebra libraries that will type-check matrices so that a 2x2 matrix can't be added to a 2x3 matrix (but then you can have a dynamic matrix that will error only in runtime), like https://nalgebra.org/ and others.

Maybe start by looking at https://nalgebra.org/ to see what rust math libraries might look like

And Nalgebra, while better, also seems to have slowed down on commits and responses to issues and PRs. I have a PR there for a relatively simple wrapper type for row vectors which was explicitly requested by a maintainer, which hasn't even gotten a comment since for two weeks.

nalgebra (similar to Eigen in cpp)

nalgebra

nalgebra is for linear algebra.

Take a look into math libraries, like glam, nalgebra, and cgmath. I've only used these through game engines, though, so I can't offer per-basis reviews/advice.

If you do not need GPU then I would recommend looking into Eigen in C++, nalgebra in Rust (with a BLAS in both cases for improved performance) or one of the above options (Julia / Python+JAX).

Rust https://github.com/Crazytieguy/advent-2021/blob/master/src/bin/day22/main.rs Imagining the geometry of this was very tricky for me. For a while I contemplated if calculating the intersection of each pair of cuboids would give me enough information to know how many cubes are on at the end, and finally decided that I would also have to calculate the intersections of those and so on, so I gave up. Instead I decided that my state will be a vector of cuboids that are garuanteed to be non overlapping, and on each command I would subtract the current cuboid from each of these non overlapping cuboids (leaving 1 to 6 cuboids depending on intersection), and finally either add in the current cuboid (for on command) or leave it out (for off).