rand_distr: Add Zipf distribution

rand_distr/CHANGELOG.md

@@ -4,6 +4,9 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+- New `Zeta` and `Zipf` distributions (#1136)
+
 ## [0.4.1] - 2021-06-15
 - Empirically test PDF of normal distribution (#1121)
 - Correctly document `no_std` support (#1100)

rand_distr/benches/src/distributions.rs

@@ -195,6 +195,12 @@ fn bench(c: &mut Criterion<CyclesPerByte>) {
     distr_float!(g, "poisson", f64, Poisson::new(4.0).unwrap());
     }
 
+    {
+    let mut g = c.benchmark_group("zipf");
+    distr_float!(g, "zipf", f64, Zipf::new(10, 1.5).unwrap());
+    distr_float!(g, "zeta", f64, Zeta::new(1.5).unwrap());
+    }
+
     {
     let mut g = c.benchmark_group("bernoulli");
     distr!(g, "bernoulli", bool, Bernoulli::new(0.18).unwrap());

rand_distr/src/lib.rs

@@ -56,6 +56,8 @@
 //!   - [`Poisson`] distribution
 //!   - [`Exp`]onential distribution, and [`Exp1`] as a primitive
 //!   - [`Weibull`] distribution
+//!   - [`Zeta`] distribution
+//!   - [`Zipf`] distribution
 //! - Gamma and derived distributions:
 //!   - [`Gamma`] distribution
 //!   - [`ChiSquared`] distribution
@@ -115,6 +117,7 @@ pub use self::unit_circle::UnitCircle;
 pub use self::unit_disc::UnitDisc;
 pub use self::unit_sphere::UnitSphere;
 pub use self::weibull::{Error as WeibullError, Weibull};
+pub use self::zipf::{ZetaError, Zeta, ZipfError, Zipf};
 #[cfg(feature = "alloc")]
 #[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
 pub use rand::distributions::{WeightedError, WeightedIndex};
@@ -198,4 +201,4 @@ mod unit_sphere;
 mod utils;
 mod weibull;
 mod ziggurat_tables;
-
+mod zipf;