1 use plotters::prelude::*;
2
3 use rand::SeedableRng;
4 use rand_distr::{Distribution, Normal};
5 use rand_xorshift::XorShiftRng;
6
7 use itertools::Itertools;
8
9 use num_traits::sign::Signed;
10
main() -> Result<(), Box<dyn std::error::Error>>11 fn main() -> Result<(), Box<dyn std::error::Error>> {
12 let data = generate_random_data();
13 let down_sampled = down_sample(&data[..]);
14
15 let root =
16 BitMapBackend::new("plotters-doc-data/errorbar.png", (1024, 768)).into_drawing_area();
17
18 root.fill(&WHITE)?;
19
20 let mut chart = ChartBuilder::on(&root)
21 .caption("Linear Function with Noise", ("sans-serif", 60))
22 .margin(10)
23 .set_label_area_size(LabelAreaPosition::Left, 40)
24 .set_label_area_size(LabelAreaPosition::Bottom, 40)
25 .build_ranged(-10f64..10f64, -10f64..10f64)?;
26
27 chart.configure_mesh().draw()?;
28
29 chart
30 .draw_series(LineSeries::new(data, &GREEN.mix(0.3)))?
31 .label("Raw Data")
32 .legend(|(x, y)| PathElement::new(vec![(x, y), (x + 20, y)], &GREEN));
33
34 chart.draw_series(LineSeries::new(
35 down_sampled.iter().map(|(x, _, y, _)| (*x, *y)),
36 &BLUE,
37 ))?;
38
39 chart
40 .draw_series(
41 down_sampled.iter().map(|(x, yl, ym, yh)| {
42 ErrorBar::new_vertical(*x, *yl, *ym, *yh, BLUE.filled(), 20)
43 }),
44 )?
45 .label("Down-sampled")
46 .legend(|(x, y)| PathElement::new(vec![(x, y), (x + 20, y)], &BLUE));
47
48 chart
49 .configure_series_labels()
50 .background_style(WHITE.filled())
51 .draw()?;
52
53 Ok(())
54 }
55
generate_random_data() -> Vec<(f64, f64)>56 fn generate_random_data() -> Vec<(f64, f64)> {
57 let norm_dist = Normal::new(0.0, 1.0).unwrap();
58 let mut x_rand = XorShiftRng::from_seed(*b"MyFragileSeed123");
59 let x_iter = norm_dist.sample_iter(&mut x_rand);
60 x_iter
61 .take(20000)
62 .filter(|x| x.abs() <= 4.0)
63 .zip(-10000..10000)
64 .map(|(yn, x)| {
65 (
66 x as f64 / 1000.0,
67 x as f64 / 1000.0 + yn * x as f64 / 10000.0,
68 )
69 })
70 .collect()
71 }
72
down_sample(data: &[(f64, f64)]) -> Vec<(f64, f64, f64, f64)>73 fn down_sample(data: &[(f64, f64)]) -> Vec<(f64, f64, f64, f64)> {
74 let down_sampled: Vec<_> = data
75 .iter()
76 .group_by(|x| (x.0 * 1.0).round() / 1.0)
77 .into_iter()
78 .map(|(x, g)| {
79 let mut g: Vec<_> = g.map(|(_, y)| *y).collect();
80 g.sort_by(|a, b| a.partial_cmp(b).unwrap());
81 (
82 x,
83 g[0],
84 g.iter().sum::<f64>() / g.len() as f64,
85 g[g.len() - 1],
86 )
87 })
88 .collect();
89 down_sampled
90 }
91
