levgen-benchmarks

Here's the compare view for an overview of the changes dbaupp applied to the original code: https://github.com/huonw/levgen-benchmarks/compare/logicchai... edit: wrong addition left thereafter for posterity, ignore it (apparently Go uses ISAAC so the change to XorShiftRng might be unfair to Go (though it's trailing anyway). I expect C uses the standard libc generator?)

The Rust code was very non-idiomatic, and is dramatically disadvantaged by using the ISAAC random number generator (which is cryptographically secure, and so quite slow). By rewriting it to use more iterators (for non-bounds checked vector access), more vector-building functions (specifically, `vec::with_capacity` and `vec::from_fn`), and a non-cryptographically secure RNG[1], I get the following: Rust 0.34 Rust isaac 0.57 Rust orig 0.70 Clang 0.42 GCC 0.36 My rewritten version: https://github.com/huonw/levgen-benchmarks/blob/master/R.rs (I didn't bother implementing seeding of the RNG for this, so it's the same result every time. Edit: implemented now, no performance change.) [1]: The new RNG is XorShiftRng, which is also in the standard library, and actually has far better randomness properties than most pl