#gcd #lcm #division #integer

gcdn

An algorithmically faster implementation of variadic GCD

2 unstable releases

Uses new Rust 2024

0.2.0 Oct 28, 2025
0.1.0 Oct 28, 2025

#981 in Math

MIT/Apache

20KB
602 lines

gcdn

gcdn is an algorithmically faster implementation of variadic GCD. It outperforms chaining implementations such as gcd(gcd(a,b), c) by over 40% in some workloads.

This is a novel algorithm that I wrote in 2017 as part of some experiments in C# and ported to Rust in 2021, but have continually delayed releasing out of hopes of writing a paper about it someday.

The main idea is to sort, and then do some binary-euclidean-algorithm tricks that use knowledge of all arguments to accelerate evaluation.

Please consult the documentation for more information.

Add it to your Cargo.toml:

[dependencies]
gcdn = "0.1"

Example

assert_eq!(gcd4(15, 120, 30, 25), 5u32);

// needs mutable access because it runs the algorithm in-place to avoid allocation
assert_eq!(gcdn(&mut [15, 120, 30, 25]), 5u32);

License

gcdn is dual-licensed under either:

at your option.

Your contributions

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

Dependencies

~140KB