As a best-selling author, I invite you to explore my books on Amazon . Don't forget to follow me on Medium and show your support. Thank you! Your support means the world! I remember the first time I needed a function that worked on arrays of different sizes. The obvious way was to write a separate version for each size. For a 3-element vector, write one function. For a 4-element vector, write another. For a 5-element… you get the idea. It felt wrong. Code duplication is the enemy of maintainability, and repeating the same logic ten times just to handle different lengths was a recipe for bugs. The alternative was using slices. Pass a &[f64] with a runtime length. Inside the function, loop over the slice with a bounds check at every iteration. That works, but the compiler can't know the length at compile time. It can't unroll the loop. It can't eliminate the bounds check. Every call pays a small performance tax, even when the length is fixed from the start.…