Nesting Structures from Flat Indexes

I don't always use recursion; but when I do, I don't always use recursion.

Reading time: about 4 minutes (961 words).
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SQL databases are still one of the best ways of storing relational data, but sometimes you hit a wall transferring your representation to or from a table based layout.

Say we have a table full of Foos, where some Foos may have other Foo parents. This can easily be represented in a table with some unique primary key id, a secondary key parent, which joins to the parent's id, and whatever data Foo may hold. Retrieving this table into a rust data structure, we'd find ourselves with something like Vec<Foo>, where Foo is defined as

struct Foo {
    id: i32,
    parent: Option<i32>,
    data: String,
}

This isn't really the best way to represent these data though, what you really want is more akin to

struct Bar {
    id: i32,
    data: String,
    children: Vec<Bar>,
}

Clustering Tangent Spheres

Make yourself a little nest of eggs. Where your eggs are perfectly round and magically float in free space.

Reading time: about 7 minutes (1430 words).
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So you want to do some sphere packing to make your inflatable space habitats for deployment on the Moon and Mars snug and cozy. Perfectly straightforward you think to yourself; since one can start with a triplet of spheres tangent pairwise by placing one at some origin on a 2D plane, extending the second out in the \(x\) direction and completing the triangle by identifying the third sphere's position based on the radii of all three.

A sphere triplet
An initial sphere triplet located on the vertices of a triangle with side lengths constructed from sphere radii: \(a=r_B+r_C, b=r_A+r_C, c=r_A+r_B\)

Code Coverage in Rust

Productivity tools you employ to make yourself more efficient that actually take up most of your productive time.

Reading time: about 5 minutes (1038 words).
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One side project that has been sitting by the wayside since completing my PhD has been to polish up and publish Wafer: my fancy 3D wavefunction solver. For reasons, one of which is mostly structured procratstination, this polishing ended up being a port/re-write in Rust. Delving into the Rust ecosystem has been fun and if you check Wafer's commit history you'll notice large rewrites again and again as I basically play around with things; having no real development schedule or design restrictions.

It may seem a little counter intuitive then, that I'm also trying at the same time to learn all the rigid structures of software development. Proper documentation, testing, error handling, data structures etc.