fraug/augmenters/
drift.rs

1use super::base::Augmenter;
2use rand::Rng;
3use tracing::{info_span};
4/// Drifts the value of a time series by a random value at each point in the series.
5/// 
6/// The drift is linear between the points, bounded by `max_drift`.
7/// 
8/// The number of drift points is specified by `n_drift_points`.
9pub struct Drift {
10    pub name: String,
11    pub max_drift: f64,
12    pub n_drift_points: usize,
13    p: f64,
14}
15
16impl Drift {
17    /// new drift augmenter
18    pub fn new(max_drift: f64, n_drift_points: usize) -> Self {
19        Drift {
20            name: "Drift".to_string(),
21            max_drift,
22            n_drift_points: n_drift_points.max(2), // at least 2 points
23            p: 1.0,
24        }
25    }
26
27    fn make_drift(&self, len: usize) -> Vec<f64> {
28        let mut rng = rand::rng();
29        let n = self.n_drift_points.min(len);
30        let mut drift_points = Vec::with_capacity(n);
31        for _ in 0..n {
32            drift_points.push(rng.random_range(-self.max_drift..=self.max_drift));
33        }
34        // Linear interpolation between drift points
35        let mut drift = vec![0.0; len];
36        let seg_len = len as f64 / (n - 1) as f64;
37        for i in 0..len {
38            let pos = i as f64 / seg_len;
39            let left = pos.floor() as usize;
40            let right = pos.ceil() as usize;
41            let alpha = pos - left as f64;
42            let left_val = drift_points[left.min(n - 1)];
43            let right_val = drift_points[right.min(n - 1)];
44            drift[i] = (1.0 - alpha) * left_val + alpha * right_val;
45        }
46        drift
47    }
48}
49
50impl Augmenter for Drift {
51    fn augment_one(&self, x: &[f64]) -> Vec<f64> {
52        let span = info_span!("", step = "augment_one");
53        let _enter = span.enter();
54        let drift = self.make_drift(x.len());
55        x.iter().zip(drift.iter()).map(|(xi, di)| xi + di).collect()
56    }
57
58    fn get_probability(&self) -> f64 {
59        self.p
60    }
61
62    fn set_probability(&mut self, probability: f64) {
63        self.p = probability;
64    }
65
66    fn get_name(&self) ->String {
67        self.name.clone()
68    }
69}
fraug/augmenters/drift.rs

fraug/augmenters/
drift.rs
