1 use plotters::prelude::*;
2
3 use rand::SeedableRng;
4 use rand_distr::{Distribution, Normal};
5 use rand_xorshift::XorShiftRng;
6
7 use num_traits::sign::Signed;
8
9 const OUT_FILE_NAME: &'static str = "plotters-doc-data/normal-dist2.png";
main() -> Result<(), Box<dyn std::error::Error>>10 fn main() -> Result<(), Box<dyn std::error::Error>> {
11 let sd = 0.60;
12
13 let random_points: Vec<f64> = {
14 let norm_dist = Normal::new(0.0, sd).unwrap();
15 let mut x_rand = XorShiftRng::from_seed(*b"MyFragileSeed123");
16 let x_iter = norm_dist.sample_iter(&mut x_rand);
17 x_iter.take(5000).filter(|x| x.abs() <= 4.0).collect()
18 };
19
20 let root = BitMapBackend::new(OUT_FILE_NAME, (1024, 768)).into_drawing_area();
21
22 root.fill(&WHITE)?;
23
24 let mut chart = ChartBuilder::on(&root)
25 .margin(5)
26 .caption("1D Gaussian Distribution Demo", ("sans-serif", 30))
27 .set_label_area_size(LabelAreaPosition::Left, 60)
28 .set_label_area_size(LabelAreaPosition::Bottom, 60)
29 .set_label_area_size(LabelAreaPosition::Right, 60)
30 .build_cartesian_2d(-4f64..4f64, 0f64..0.1)?
31 .set_secondary_coord(
32 (-4f64..4f64).step(0.1).use_round().into_segmented(),
33 0u32..500u32,
34 );
35
36 chart
37 .configure_mesh()
38 .disable_x_mesh()
39 .disable_y_mesh()
40 .y_label_formatter(&|y| format!("{:.0}%", *y * 100.0))
41 .y_desc("Percentage")
42 .draw()?;
43
44 chart.configure_secondary_axes().y_desc("Count").draw()?;
45
46 let actual = Histogram::vertical(chart.borrow_secondary())
47 .style(GREEN.filled())
48 .margin(3)
49 .data(random_points.iter().map(|x| (*x, 1)));
50
51 chart
52 .draw_secondary_series(actual)?
53 .label("Observed")
54 .legend(|(x, y)| Rectangle::new([(x, y - 5), (x + 10, y + 5)], GREEN.filled()));
55
56 let pdf = LineSeries::new(
57 (-400..400).map(|x| x as f64 / 100.0).map(|x| {
58 (
59 x,
60 (-x * x / 2.0 / sd / sd).exp() / (2.0 * std::f64::consts::PI * sd * sd).sqrt()
61 * 0.1,
62 )
63 }),
64 &RED,
65 );
66
67 chart
68 .draw_series(pdf)?
69 .label("PDF")
70 .legend(|(x, y)| PathElement::new(vec![(x, y), (x + 20, y)], RED.filled()));
71
72 chart.configure_series_labels().draw()?;
73
74 // To avoid the IO failure being ignored silently, we manually call the present function
75 root.present().expect("Unable to write result to file, please make sure 'plotters-doc-data' dir exists under current dir");
76 println!("Result has been saved to {}", OUT_FILE_NAME);
77
78 Ok(())
79 }
80 #[test]
entry_point()81 fn entry_point() {
82 main().unwrap()
83 }
84
