arcweight 0.3.0

A high-performance, modular library for weighted finite state transducers with comprehensive examples and benchmarks
Documentation 
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//! Connect operation benchmarks
//!
//! These benchmarks measure the performance of FST connection operations
//! (removing unreachable states) across different FST sizes and structures.

use arcweight::prelude::*;
use criterion::{criterion_group, criterion_main, Criterion};
use std::hint::black_box;

/// Create an FST with unreachable states
fn create_fst_with_unreachable(size: usize, unreachable_count: usize) -> VectorFst<TropicalWeight> {
    let mut fst = VectorFst::new();
    let mut states = Vec::new();

    // Add reachable states
    for _ in 0..size {
        states.push(fst.add_state());
    }

    // Add unreachable states
    let unreachable_start = states.len();
    for _ in 0..unreachable_count {
        states.push(fst.add_state());
    }

    fst.set_start(states[0]);
    fst.set_final(states[size - 1], TropicalWeight::one());

    // Add transitions in reachable part
    for i in 0..size - 1 {
        fst.add_arc(
            states[i],
            Arc::new(
                (i % 26 + 97) as u32,
                (i % 26 + 97) as u32,
                TropicalWeight::new(1.0),
                states[i + 1],
            ),
        );
    }

    // Add transitions in unreachable part (self-loops and internal connections)
    for i in unreachable_start..states.len() {
        if i < states.len() - 1 {
            fst.add_arc(
                states[i],
                Arc::new(
                    ((i - unreachable_start) % 26 + 97) as u32,
                    ((i - unreachable_start) % 26 + 97) as u32,
                    TropicalWeight::new(1.0),
                    states[i + 1],
                ),
            );
        }
        // Add self-loop
        fst.add_arc(
            states[i],
            Arc::new(
                ((i - unreachable_start + 10) % 26 + 97) as u32,
                ((i - unreachable_start + 10) % 26 + 97) as u32,
                TropicalWeight::new(0.5),
                states[i],
            ),
        );
    }

    fst
}

fn bench_connect_with_unreachable(c: &mut Criterion) {
    let mut group = c.benchmark_group("connect_with_unreachable");

    for size in [50, 200, 500, 1000].iter() {
        let unreachable_count = size / 4;
        let fst = create_fst_with_unreachable(*size, unreachable_count);

        group.bench_function(format!("size_{size}_unreachable_{unreachable_count}"), |b| {
            b.iter(|| {
                let result: VectorFst<TropicalWeight> = connect(black_box(&fst)).unwrap();
                black_box(result)
            })
        });
    }

    group.finish();
}

fn bench_connect_fully_connected(c: &mut Criterion) {
    let mut group = c.benchmark_group("connect_fully_connected");

    for size in [50, 200, 500, 1000].iter() {
        let mut fst = VectorFst::new();
        let states: Vec<_> = (0..*size).map(|_| fst.add_state()).collect();

        fst.set_start(states[0]);
        fst.set_final(states[size - 1], TropicalWeight::one());

        // Create fully connected graph
        for i in 0..size - 1 {
            fst.add_arc(
                states[i],
                Arc::new(
                    (i % 26 + 97) as u32,
                    (i % 26 + 97) as u32,
                    TropicalWeight::new(1.0),
                    states[i + 1],
                ),
            );
        }

        group.bench_function(format!("fully_connected_{size}"), |b| {
            b.iter(|| {
                let result: VectorFst<TropicalWeight> = connect(black_box(&fst)).unwrap();
                black_box(result)
            })
        });
    }

    group.finish();
}

criterion_group!(
    benches,
    bench_connect_with_unreachable,
    bench_connect_fully_connected
);
criterion_main!(benches);