[okaleniuk]

Good for you! You did everything right: measure always, fix the bottleneck if possible, rewrite if necessary.

A little tip, you don't have to compare actual distances, you can compare squared distances just as well. Then in `norm < max_dist`, you don't have to do a `sqrt()` for every `norm`. Saves a few CPU ticks as well.

I once rewrote a GDI+ point transformation routine in pure C# and got 200x speedup just because the routine was riddled with needless virtual constructors, copying type conversions, and something called CreateInstanceSlow. Ten years after, I gathered a few of these anecdotes and wrote the Geometry for Programmers book (https://www.manning.com/books/geometry-for-programmers) with its main message: when you know geometry behind your tools, you can either use them efficiently, or rewrite them completely.

[masklinn]

The author did talk about it on reddit, but explained that for the purpose of the blog post they wanted to focus on the big stuff and profiling-guided optimisation of the process: https://reddit.com/r/rust/comments/125pbq0/blog_post_making_...

[ZeroCool2u]

The ignore the square root while computing/comparing distances trick is a great one. That's how I got to the top of the performance leaderboard in my first algorithms class.