[jedbrown]

"random index lookups into sparse arrays" is almost always an anti-pattern in HPC. Successful data structures are designed for streaming access and fine-grained parallelism, even when the problem domain seems irregular. Bounds checks sometimes matter (less in the logic than in inhibiting vectorization), but can sometimes be safely eliminated using existential lifetimes/branding or different control flow.

Rust is starting to make inroads in HPC/scientific computing. The libraries have a ways to go for widespread end-to-end adoption, but to give a concrete example, a current project has drastically beaten OpenBLAS across a suite of matrix factorizations. It was developed over a few months by one person with much less arch-specific or unsafe code. (The library is on GitHub/crates.io, but the author isn't ready for a public announcement so I won't link it yet.) Expect to see lots more Rust in HPC over the next few years.

[aragilar]

If you're talking about the library I think you are, from what I could see there weren't any tests of the numerics (nor comparisons of the output from competing libraries), which is quite concerning?

I do think Rust will make inroads, but more because of better WASM toolchain,so loading data into the browser is significantly easier than with JS (e.g. https://crates.io/crates/moc).