flow_pacmap/
weights.rs

1//! Three-phase weight schedule from Algorithm 1 of Wang et al. 2021.
2
3/// Weights for the three pair types at a given iteration.
4#[derive(Debug, Clone, Copy)]
5pub struct Weights {
6    pub w_nb: f32,
7    pub w_mn: f32,
8    pub w_fp: f32,
9}
10
11/// Compute weights for iteration `t` (1-indexed) given phase boundaries.
12///
13/// Phases are defined by `phase_iters = [p1, p2, p3]`:
14/// - Phase 1: t in [1, p1]          — wNB=2, wMN decreases 1000→3, wFP=1
15/// - Phase 2: t in [p1+1, p1+p2]   — wNB=3, wMN=3, wFP=1
16/// - Phase 3: t in [p1+p2+1, total] — wNB=1, wMN=0, wFP=1
17pub fn weights_at(t: usize, phase_iters: &[usize; 3]) -> Weights {
18    let p1 = phase_iters[0];
19    let p2 = phase_iters[1];
20
21    if t <= p1 {
22        // Phase 1: wMN decreases linearly from 1000 to 3 over p1 iterations
23        let progress = if p1 > 1 { (t - 1) as f32 / (p1 - 1) as f32 } else { 1.0 };
24        let w_mn = 1000.0 * (1.0 - progress) + 3.0 * progress;
25        Weights { w_nb: 2.0, w_mn, w_fp: 1.0 }
26    } else if t <= p1 + p2 {
27        // Phase 2: fixed weights
28        Weights { w_nb: 3.0, w_mn: 3.0, w_fp: 1.0 }
29    } else {
30        // Phase 3: wMN = 0, focus on local structure
31        Weights { w_nb: 1.0, w_mn: 0.0, w_fp: 1.0 }
32    }
33}
34
35#[cfg(test)]
36mod tests {
37    use super::*;
38    use approx::assert_abs_diff_eq;
39
40    #[test]
41    fn phase_1_start() {
42        let w = weights_at(1, &[100, 100, 250]);
43        assert_abs_diff_eq!(w.w_nb, 2.0);
44        assert_abs_diff_eq!(w.w_mn, 1000.0, epsilon = 0.01);
45        assert_abs_diff_eq!(w.w_fp, 1.0);
46    }
47
48    #[test]
49    fn phase_1_end() {
50        let w = weights_at(100, &[100, 100, 250]);
51        assert_abs_diff_eq!(w.w_mn, 3.0, epsilon = 0.01);
52    }
53
54    #[test]
55    fn phase_2() {
56        let w = weights_at(150, &[100, 100, 250]);
57        assert_abs_diff_eq!(w.w_nb, 3.0);
58        assert_abs_diff_eq!(w.w_mn, 3.0);
59    }
60
61    #[test]
62    fn phase_3() {
63        let w = weights_at(300, &[100, 100, 250]);
64        assert_abs_diff_eq!(w.w_nb, 1.0);
65        assert_abs_diff_eq!(w.w_mn, 0.0);
66        assert_abs_diff_eq!(w.w_fp, 1.0);
67    }
68}
flow_pacmap/weights.rs

flow_pacmap/
weights.rs
