rucrf: Conditional Random Fields implemented in pure Rust

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rucrf contains a trainer and an estimator for Conditional Random Fields (CRFs). This library supports: - [x] lattices with variable length edges, - [x] L1 and L2 regularization, and - [x] multi-threading during training.

Examples

```rust use std::num::NonZeroU32;

use rucrf::{Edge, FeatureProvider, FeatureSet, Lattice, Model, Trainer};

// Train: // 京(kyo) 都(to) // 東(to) 京(kyo) // 京(kei) 浜(hin) // 京(kyo) の(no) 都(miyako) // // Test: // 水(mizu) の(no) 都(miyako) // // Features: // 京: 1, 都: 2, 東: 3, 浜: 4, の: 5, 水: 6 // // Labels: // 京kyo: 1, 都to: 2, 東to: 3, 京kei: 4, 浜hin: 5, のno: 6, 都mikako: 7, 水mizu: 8

let mut provider = FeatureProvider::new(); provider.addfeatureset(FeatureSet::new( &[NonZeroU32::new(1).unwrap()], &[NonZeroU32::new(1)], &[NonZeroU32::new(1)], )); provider.addfeatureset(FeatureSet::new( &[NonZeroU32::new(2).unwrap()], &[NonZeroU32::new(2)], &[NonZeroU32::new(2)], )); provider.addfeatureset(FeatureSet::new( &[NonZeroU32::new(3).unwrap()], &[NonZeroU32::new(3)], &[NonZeroU32::new(3)], )); provider.addfeatureset(FeatureSet::new( &[NonZeroU32::new(1).unwrap()], &[NonZeroU32::new(4)], &[NonZeroU32::new(4)], )); provider.addfeatureset(FeatureSet::new( &[NonZeroU32::new(4).unwrap()], &[NonZeroU32::new(5)], &[NonZeroU32::new(5)], )); provider.addfeatureset(FeatureSet::new( &[NonZeroU32::new(5).unwrap()], &[NonZeroU32::new(6)], &[NonZeroU32::new(6)], )); provider.addfeatureset(FeatureSet::new( &[NonZeroU32::new(2).unwrap()], &[NonZeroU32::new(7)], &[NonZeroU32::new(7)], )); provider.addfeatureset(FeatureSet::new( &[NonZeroU32::new(6).unwrap()], &[NonZeroU32::new(8)], &[NonZeroU32::new(8)], ));

let mut lattices = vec![];

// 京都 (kyo to) let mut lattice = Lattice::new(2)?; lattice.addedge(0, Edge::new(1, NonZeroU32::new(1).unwrap()))?; // kyo lattice.addedge(1, Edge::new(2, NonZeroU32::new(2).unwrap()))?; // to

lattice.addedge(0, Edge::new(1, NonZeroU32::new(4).unwrap()))?; // kei lattice.addedge(1, Edge::new(2, NonZeroU32::new(7).unwrap()))?; // miyako

lattices.push(lattice);

// 東京 (to kyo) let mut lattice = Lattice::new(2)?; lattice.addedge(0, Edge::new(1, NonZeroU32::new(3).unwrap()))?; // to lattice.addedge(1, Edge::new(2, NonZeroU32::new(1).unwrap()))?; // kyo

lattice.add_edge(1, Edge::new(2, NonZeroU32::new(4).unwrap()))?; // kei

lattices.push(lattice);

// 京浜 (kei hin) let mut lattice = Lattice::new(2)?; lattice.addedge(0, Edge::new(1, NonZeroU32::new(4).unwrap()))?; // kei lattice.addedge(1, Edge::new(2, NonZeroU32::new(5).unwrap()))?; // hin

lattice.add_edge(0, Edge::new(1, NonZeroU32::new(1).unwrap()))?; // kyo

lattices.push(lattice);

// 京の都 (kyo no miyako) let mut lattice = Lattice::new(3)?; lattice.addedge(0, Edge::new(1, NonZeroU32::new(1).unwrap()))?; // kyo lattice.addedge(1, Edge::new(2, NonZeroU32::new(6).unwrap()))?; // no lattice.add_edge(2, Edge::new(3, NonZeroU32::new(7).unwrap()))?; // miyako

lattice.addedge(0, Edge::new(1, NonZeroU32::new(4).unwrap()))?; // kei lattice.addedge(2, Edge::new(3, NonZeroU32::new(2).unwrap()))?; // to

lattices.push(lattice);

// Generates a model let trainer = Trainer::new(); let model = trainer.train(&lattices, provider);

// 水の都 (mizu no miyako) let mut lattice = Lattice::new(3)?; lattice.addedge(0, Edge::new(1, NonZeroU32::new(8).unwrap()))?; // mizu lattice.addedge(1, Edge::new(2, NonZeroU32::new(6).unwrap()))?; // no lattice.addedge(2, Edge::new(3, NonZeroU32::new(2).unwrap()))?; // to lattice.addedge(2, Edge::new(3, NonZeroU32::new(7).unwrap()))?; // miyako

let (path, ) = model.searchbest_path(&lattice);

assert_eq!(vec![ Edge::new(1, NonZeroU32::new(8).unwrap()), Edge::new(2, NonZeroU32::new(6).unwrap()), Edge::new(3, NonZeroU32::new(7).unwrap()), ], path); ```

License

Licensed under either of

at your option.

Contribution

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