aboutsummaryrefslogtreecommitdiff
path: root/rand/src/distributions/pareto.rs
diff options
context:
space:
mode:
Diffstat (limited to 'rand/src/distributions/pareto.rs')
-rw-r--r--rand/src/distributions/pareto.rs74
1 files changed, 0 insertions, 74 deletions
diff --git a/rand/src/distributions/pareto.rs b/rand/src/distributions/pareto.rs
deleted file mode 100644
index 744a157..0000000
--- a/rand/src/distributions/pareto.rs
+++ /dev/null
@@ -1,74 +0,0 @@
-// 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 Pareto distribution.
-
-use Rng;
-use distributions::{Distribution, OpenClosed01};
-
-/// Samples floating-point numbers according to the Pareto distribution
-///
-/// # Example
-/// ```
-/// use rand::prelude::*;
-/// use rand::distributions::Pareto;
-///
-/// let val: f64 = SmallRng::from_entropy().sample(Pareto::new(1., 2.));
-/// println!("{}", val);
-/// ```
-#[derive(Clone, Copy, Debug)]
-pub struct Pareto {
- scale: f64,
- inv_neg_shape: f64,
-}
-
-impl Pareto {
- /// Construct a new Pareto distribution with given `scale` and `shape`.
- ///
- /// In the literature, `scale` is commonly written as x<sub>m</sub> or k and
- /// `shape` is often written as α.
- ///
- /// # Panics
- ///
- /// `scale` and `shape` have to be non-zero and positive.
- pub fn new(scale: f64, shape: f64) -> Pareto {
- assert!((scale > 0.) & (shape > 0.));
- Pareto { scale, inv_neg_shape: -1.0 / shape }
- }
-}
-
-impl Distribution<f64> for Pareto {
- fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f64 {
- let u: f64 = rng.sample(OpenClosed01);
- self.scale * u.powf(self.inv_neg_shape)
- }
-}
-
-#[cfg(test)]
-mod tests {
- use distributions::Distribution;
- use super::Pareto;
-
- #[test]
- #[should_panic]
- fn invalid() {
- Pareto::new(0., 0.);
- }
-
- #[test]
- fn sample() {
- let scale = 1.0;
- let shape = 2.0;
- let d = Pareto::new(scale, shape);
- let mut rng = ::test::rng(1);
- for _ in 0..1000 {
- let r = d.sample(&mut rng);
- assert!(r >= scale);
- }
- }
-}