Use a flat vector in Damerau-Levenshtein

Instead of representing a 2x2 grid with a vector of vectors, just use a single
vector to improve performance. We can do this since the dimensions are fixed.

This method was suggested by @lovasoa as an alternative to adding a dependency
on the ndarray crate.

In my benchmark testing, the new approach is about as fast using ndarray. On my
machine, the original approach takes about 22,000 ns/iter, whereas the new
approach takes about 17,000 ns/iter.

See https://github.com/dguo/strsim-rs/issues/34 for more context.
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tree: 23ec6a818968a415add5c844c59c4e22ddf7d0ce
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  7. LICENSE
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  9. benches/
  10. dev
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  12. tests/
README.md

strsim-rs Crates.io Crates.io build status

Rust implementations of string similarity metrics:

The normalized versions return values between 0.0 and 1.0, where 1.0 means an exact match.

There are also generic versions of the functions for non-string inputs.

Installation

strsim is available on crates.io. Add it to your Cargo.toml:

[dependencies]
strsim = "0.9.0"

Usage

Go to Docs.rs for the full documentation. You can also clone the repo, and run $ cargo doc --open.

Examples

extern crate strsim;

use strsim::{hamming, levenshtein, normalized_levenshtein, osa_distance,
             damerau_levenshtein, normalized_damerau_levenshtein, jaro,
             jaro_winkler};

fn main() {
    match hamming("hamming", "hammers") {
        Ok(distance) => assert_eq!(3, distance),
        Err(why) => panic!("{:?}", why)
    }

    assert_eq!(levenshtein("kitten", "sitting"), 3);

    assert!((normalized_levenshtein("kitten", "sitting") - 0.571).abs() < 0.001);

    assert_eq!(osa_distance("ac", "cba"), 3);

    assert_eq!(damerau_levenshtein("ac", "cba"), 2);

    assert!((normalized_damerau_levenshtein("levenshtein", "löwenbräu") - 0.272).abs() <
            0.001);

    assert!((jaro("Friedrich Nietzsche", "Jean-Paul Sartre") - 0.392).abs() <
            0.001);

    assert!((jaro_winkler("cheeseburger", "cheese fries") - 0.911).abs() <
            0.001);
}

Using the generic versions of the functions:

extern crate strsim;

use strsim::generic_levenshtein;

fn main() {
    assert_eq!(2, generic_levenshtein(&[1, 2, 3], &[0, 2, 5]));
}

Contributing

If you don't want to install Rust itself, you can run $ ./dev for a development CLI if you have Docker installed.

Benchmarks require a Nightly toolchain. Run $ cargo +nightly bench.

License

MIT