1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
|
// Copyright 2018 Developers of the Rand project.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! The Weibull distribution.
#![allow(deprecated)]
use crate::Rng;
use crate::distributions::{Distribution, OpenClosed01};
/// Samples floating-point numbers according to the Weibull distribution
#[deprecated(since="0.7.0", note="moved to rand_distr crate")]
#[derive(Clone, Copy, Debug)]
pub struct Weibull {
inv_shape: f64,
scale: f64,
}
impl Weibull {
/// Construct a new `Weibull` distribution with given `scale` and `shape`.
///
/// # Panics
///
/// `scale` and `shape` have to be non-zero and positive.
pub fn new(scale: f64, shape: f64) -> Weibull {
assert!((scale > 0.) & (shape > 0.));
Weibull { inv_shape: 1./shape, scale }
}
}
impl Distribution<f64> for Weibull {
fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f64 {
let x: f64 = rng.sample(OpenClosed01);
self.scale * (-x.ln()).powf(self.inv_shape)
}
}
#[cfg(test)]
mod tests {
use crate::distributions::Distribution;
use super::Weibull;
#[test]
#[should_panic]
fn invalid() {
Weibull::new(0., 0.);
}
#[test]
fn sample() {
let scale = 1.0;
let shape = 2.0;
let d = Weibull::new(scale, shape);
let mut rng = crate::test::rng(1);
for _ in 0..1000 {
let r = d.sample(&mut rng);
assert!(r >= 0.);
}
}
}
|
