plotlib/
utils.rs

1use std::f64;
2use std::iter::{Skip, Zip};
3use std::slice::Iter;
4
5pub trait PairWise<T> {
6    fn pairwise(&self) -> Zip<Iter<T>, Skip<Iter<T>>>;
7}
8
9impl<T> PairWise<T> for [T] {
10    fn pairwise(&self) -> Zip<Iter<T>, Skip<Iter<T>>> {
11        self.iter().zip(self.iter().skip(1))
12    }
13}
14
15fn _mean(s: &[f64]) -> f64 {
16    s.iter().map(|v| v / s.len() as f64).sum()
17}
18
19pub fn median(s: &[f64]) -> f64 {
20    let mut s = s.to_owned();
21    s.sort_by(|a, b| a.partial_cmp(b).unwrap());
22    match s.len() % 2 {
23        0 => (s[(s.len() / 2) - 1] / 2.) + (s[(s.len() / 2)] / 2.),
24        _ => s[s.len() / 2],
25    }
26}
27
28pub fn quartiles(s: &[f64]) -> (f64, f64, f64) {
29    if s.len() == 1 {
30        return (s[0], s[0], s[0]);
31    }
32    let mut s = s.to_owned();
33    s.sort_by(|a, b| a.partial_cmp(b).unwrap());
34    let (a, b) = if s.len() % 2 == 0 {
35        s.split_at(s.len() / 2)
36    } else {
37        (&s[..(s.len() / 2)], &s[((s.len() / 2) + 1)..])
38    };
39    (median(a), median(&s), median(b))
40}
41
42/// Given a slice of numbers, return the minimum and maximum values
43pub fn range(s: &[f64]) -> (f64, f64) {
44    let mut min = f64::INFINITY;
45    let mut max = f64::NEG_INFINITY;
46    for &v in s {
47        min = min.min(v);
48        max = max.max(v);
49    }
50    (min, max)
51}
52
53/// Floor or ceiling the min or max to zero to avoid them both having the same value
54pub fn pad_range_to_zero(min: f64, max: f64) -> (f64, f64) {
55    if (min - max).abs() < std::f64::EPSILON {
56        (
57            if min > 0. { 0. } else { min },
58            if max < 0. { 0. } else { max },
59        )
60    } else {
61        (min, max)
62    }
63}
64
65#[cfg(test)]
66mod tests {
67    use super::*;
68
69    #[test]
70    fn test_pairwise() {
71        let a = [1, 2, 3, 4, 5];
72        assert_eq!(a.pairwise().next().unwrap(), (&1, &2));
73        assert_eq!(a.pairwise().last().unwrap(), (&4, &5));
74        assert_eq!(a.pairwise().len(), a.len() - 1);
75
76        let a = [1, 2];
77        assert_eq!(a.pairwise().next().unwrap(), (&1, &2));
78        assert_eq!(a.pairwise().last().unwrap(), (&1, &2));
79        assert_eq!(a.pairwise().len(), a.len() - 1);
80
81        let a = [1];
82        assert!(a.pairwise().next().is_none());
83
84        let b: Vec<f64> = vec![0.0, 0.1, 0.2];
85        assert_eq!(b.pairwise().next().unwrap(), (&0.0, &0.1));
86    }
87
88    #[test]
89    fn test_mean() {
90        // TODO should error: mean(&[]);
91        assert_eq!(_mean(&[1.]), 1.);
92        assert_eq!(_mean(&[1., 2.]), 1.5);
93        assert_eq!(_mean(&[1., 2., 3.]), 2.);
94    }
95
96    #[test]
97    fn test_median() {
98        // TODO should error: median(&[]);
99        assert_eq!(median(&[1.]), 1.);
100        assert_eq!(median(&[1., 2.]), 1.5);
101        assert_eq!(median(&[1., 2., 4.]), 2.);
102        assert_eq!(median(&[1., 2., 3., 7.]), 2.5);
103    }
104
105    #[test]
106    fn test_quartiles() {
107        // TODO should error: quartiles(&[]);
108        assert_eq!(quartiles(&[1.]), (1., 1., 1.));
109        assert_eq!(quartiles(&[1., 2.]), (1., 1.5, 2.));
110        assert_eq!(quartiles(&[1., 2., 4.]), (1., 2., 4.));
111        assert_eq!(quartiles(&[1., 2., 3., 4.]), (1.5, 2.5, 3.5));
112    }
113
114    #[test]
115    fn test_pad_range_to_zero() {
116        assert_eq!(pad_range_to_zero(2.0, 2.0), (0.0, 2.0));
117        assert_eq!(pad_range_to_zero(-2.0, 2.0), (-2.0, 2.0));
118        assert_eq!(pad_range_to_zero(-2.0, -2.0), (-2.0, 0.0));
119    }
120}
plotlib/utils.rs

plotlib/
utils.rs
