build: make rand an optional dependency

Cargo.toml

@@ -22,21 +22,26 @@ path = "src/lib.rs"
 [[bench]]
 name = "order_statistics"
 harness = false
+required-features = ["rand"]
 
 [features]
-default = ["nalgebra"]
+default = ["nalgebra", "rand"]
 nalgebra = ["dep:nalgebra"]
+rand = ["dep:rand", "nalgebra?/rand"]
 
 [dependencies]
-rand = "0.8"
 approx = "0.5.0"
 num-traits = "0.2.14"
 
+[dependencies.rand]
+version = "0.8"
+optional = true
+
 [dependencies.nalgebra]
 version = "0.32"
 optional = true
 default-features = false
-features = ["rand", "std"]
+features = ["std"]
 
 [dev-dependencies]
 criterion = "0.5"

benches/order_statistics.rs

@@ -1,4 +1,3 @@
-extern crate rand;
 extern crate statrs;
 use criterion::{black_box, criterion_group, criterion_main, BatchSize, Criterion};
 use rand::prelude::*;

src/distribution/bernoulli.rs

@@ -1,6 +1,5 @@
 use crate::distribution::{Binomial, BinomialError, Discrete, DiscreteCDF};
 use crate::statistics::*;
-use rand::Rng;
 
 /// Implements the
 /// [Bernoulli](https://en.wikipedia.org/wiki/Bernoulli_distribution)
@@ -85,8 +84,9 @@ impl std::fmt::Display for Bernoulli {
     }
 }
 
+#[cfg(feature = "rand")]
 impl ::rand::distributions::Distribution<f64> for Bernoulli {
-    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f64 {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, rng: &mut R) -> f64 {
         rng.gen_bool(self.p()) as u8 as f64
     }
 }

src/distribution/beta.rs

@@ -1,7 +1,6 @@
 use crate::distribution::{Continuous, ContinuousCDF};
 use crate::function::{beta, gamma};
 use crate::statistics::*;
-use rand::Rng;
 
 /// Implements the [Beta](https://en.wikipedia.org/wiki/Beta_distribution)
 /// distribution
@@ -121,8 +120,9 @@ impl std::fmt::Display for Beta {
     }
 }
 
+#[cfg(feature = "rand")]
 impl ::rand::distributions::Distribution<f64> for Beta {
-    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f64 {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, rng: &mut R) -> f64 {
         // Generated by sampling two gamma distributions and normalizing.
         let x = super::gamma::sample_unchecked(rng, self.shape_a, 1.0);
         let y = super::gamma::sample_unchecked(rng, self.shape_b, 1.0);

src/distribution/binomial.rs

@@ -1,7 +1,6 @@
 use crate::distribution::{Discrete, DiscreteCDF};
 use crate::function::{beta, factorial};
 use crate::statistics::*;
-use rand::Rng;
 use std::f64;
 
 /// Implements the
@@ -110,8 +109,9 @@ impl std::fmt::Display for Binomial {
     }
 }
 
+#[cfg(feature = "rand")]
 impl ::rand::distributions::Distribution<f64> for Binomial {
-    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f64 {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, rng: &mut R) -> f64 {
         (0..self.n).fold(0.0, |acc, _| {
             let n: f64 = rng.gen();
             if n < self.p {

src/distribution/categorical.rs

@@ -1,6 +1,5 @@
 use crate::distribution::{Discrete, DiscreteCDF};
 use crate::statistics::*;
-use rand::Rng;
 use std::f64;
 
 /// Implements the
@@ -124,8 +123,9 @@ impl std::fmt::Display for Categorical {
     }
 }
 
+#[cfg(feature = "rand")]
 impl ::rand::distributions::Distribution<f64> for Categorical {
-    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f64 {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, rng: &mut R) -> f64 {
         sample_unchecked(rng, &self.cdf)
     }
 }
@@ -322,7 +322,8 @@ impl Discrete<u64, f64> for Categorical {
 
 /// Draws a sample from the categorical distribution described by `cdf`
 /// without doing any bounds checking
-pub fn sample_unchecked<R: Rng + ?Sized>(rng: &mut R, cdf: &[f64]) -> f64 {
+#[cfg(feature = "rand")]
+pub fn sample_unchecked<R: ::rand::Rng + ?Sized>(rng: &mut R, cdf: &[f64]) -> f64 {
     let draw = rng.gen::<f64>() * cdf.last().unwrap();
     cdf.iter()
         .enumerate()

src/distribution/cauchy.rs

@@ -1,6 +1,5 @@
 use crate::distribution::{Continuous, ContinuousCDF};
 use crate::statistics::*;
-use rand::Rng;
 use std::f64;
 
 /// Implements the [Cauchy](https://en.wikipedia.org/wiki/Cauchy_distribution)
@@ -111,8 +110,9 @@ impl std::fmt::Display for Cauchy {
     }
 }
 
+#[cfg(feature = "rand")]
 impl ::rand::distributions::Distribution<f64> for Cauchy {
-    fn sample<R: Rng + ?Sized>(&self, r: &mut R) -> f64 {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, r: &mut R) -> f64 {
         self.location + self.scale * (f64::consts::PI * (r.gen::<f64>() - 0.5)).tan()
     }
 }

src/distribution/chi.rs

@@ -1,7 +1,6 @@
 use crate::distribution::{Continuous, ContinuousCDF};
 use crate::function::gamma;
 use crate::statistics::*;
-use rand::Rng;
 use std::f64;
 
 /// Implements the [Chi](https://en.wikipedia.org/wiki/Chi_distribution)
@@ -94,8 +93,9 @@ impl std::fmt::Display for Chi {
     }
 }
 
+#[cfg(feature = "rand")]
 impl ::rand::distributions::Distribution<f64> for Chi {
-    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f64 {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, rng: &mut R) -> f64 {
         (0..self.freedom as i64)
             .fold(0.0, |acc, _| {
                 acc + super::normal::sample_unchecked(rng, 0.0, 1.0).powf(2.0)

src/distribution/chi_squared.rs

@@ -1,6 +1,5 @@
 use crate::distribution::{Continuous, ContinuousCDF, Gamma, GammaError};
 use crate::statistics::*;
-use rand::Rng;
 use std::f64;
 
 /// Implements the
@@ -101,8 +100,9 @@ impl std::fmt::Display for ChiSquared {
     }
 }
 
+#[cfg(feature = "rand")]
 impl ::rand::distributions::Distribution<f64> for ChiSquared {
-    fn sample<R: Rng + ?Sized>(&self, r: &mut R) -> f64 {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, r: &mut R) -> f64 {
         ::rand::distributions::Distribution::sample(&self.g, r)
     }
 }

src/distribution/dirac.rs

@@ -1,6 +1,5 @@
 use crate::distribution::ContinuousCDF;
 use crate::statistics::*;
-use rand::Rng;
 
 /// Implements the [Dirac Delta](https://en.wikipedia.org/wiki/Dirac_delta_function#As_a_distribution)
 /// distribution
@@ -69,8 +68,9 @@ impl std::fmt::Display for Dirac {
     }
 }
 
+#[cfg(feature = "rand")]
 impl ::rand::distributions::Distribution<f64> for Dirac {
-    fn sample<R: Rng + ?Sized>(&self, _: &mut R) -> f64 {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, _: &mut R) -> f64 {
         self.0
     }
 }

src/distribution/dirichlet.rs

@@ -2,8 +2,7 @@ use crate::distribution::Continuous;
 use crate::function::gamma;
 use crate::prec;
 use crate::statistics::*;
-use nalgebra::{Const, Dim, Dyn, OMatrix, OVector};
-use rand::Rng;
+use nalgebra::{Dim, Dyn, OMatrix, OVector};
 use std::f64;
 
 /// Implements the
@@ -192,16 +191,17 @@ where
     }
 }
 
+#[cfg(feature = "rand")]
 impl<D> ::rand::distributions::Distribution<OVector<f64, D>> for Dirichlet<D>
 where
     D: Dim,
     nalgebra::DefaultAllocator: nalgebra::allocator::Allocator<f64, D>,
 {
-    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> OVector<f64, D> {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, rng: &mut R) -> OVector<f64, D> {
         let mut sum = 0.0;
         OVector::from_iterator_generic(
             self.alpha.shape_generic().0,
-            Const::<1>,
+            nalgebra::Const::<1>,
             self.alpha.iter().map(|&a| {
                 let sample = super::gamma::sample_unchecked(rng, a, 1.0);
                 sum += sample;

src/distribution/discrete_uniform.rs

@@ -1,6 +1,5 @@
 use crate::distribution::{Discrete, DiscreteCDF};
 use crate::statistics::*;
-use rand::Rng;
 
 /// Implements the [Discrete
 /// Uniform](https://en.wikipedia.org/wiki/Discrete_uniform_distribution)
@@ -75,8 +74,9 @@ impl std::fmt::Display for DiscreteUniform {
     }
 }
 
+#[cfg(feature = "rand")]
 impl ::rand::distributions::Distribution<f64> for DiscreteUniform {
-    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f64 {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, rng: &mut R) -> f64 {
         rng.gen_range(self.min..=self.max) as f64
     }
 }

src/distribution/empirical.rs

@@ -1,7 +1,6 @@
-use crate::distribution::{ContinuousCDF, Uniform};
+use crate::distribution::ContinuousCDF;
 use crate::statistics::*;
 use core::cmp::Ordering;
-use rand::Rng;
 use std::collections::BTreeMap;
 
 #[derive(Clone, PartialEq, Debug)]
@@ -176,8 +175,11 @@ impl std::fmt::Display for Empirical {
     }
 }
 
+#[cfg(feature = "rand")]
 impl ::rand::distributions::Distribution<f64> for Empirical {
-    fn sample<R: ?Sized + Rng>(&self, rng: &mut R) -> f64 {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, rng: &mut R) -> f64 {
+        use crate::distribution::Uniform;
+
         let uniform = Uniform::new(0.0, 1.0).unwrap();
         self.__inverse_cdf(uniform.sample(rng))
     }

src/distribution/erlang.rs

@@ -1,6 +1,5 @@
 use crate::distribution::{Continuous, ContinuousCDF, Gamma, GammaError};
 use crate::statistics::*;
-use rand::Rng;
 
 /// Implements the [Erlang](https://en.wikipedia.org/wiki/Erlang_distribution)
 /// distribution
@@ -83,8 +82,9 @@ impl std::fmt::Display for Erlang {
     }
 }
 
+#[cfg(feature = "rand")]
 impl ::rand::distributions::Distribution<f64> for Erlang {
-    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f64 {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, rng: &mut R) -> f64 {
         ::rand::distributions::Distribution::sample(&self.g, rng)
     }
 }

src/distribution/exponential.rs

@@ -1,6 +1,5 @@
-use crate::distribution::{ziggurat, Continuous, ContinuousCDF};
+use crate::distribution::{Continuous, ContinuousCDF};
 use crate::statistics::*;
-use rand::Rng;
 use std::f64;
 
 /// Implements the
@@ -91,8 +90,11 @@ impl std::fmt::Display for Exp {
     }
 }
 
+#[cfg(feature = "rand")]
 impl ::rand::distributions::Distribution<f64> for Exp {
-    fn sample<R: Rng + ?Sized>(&self, r: &mut R) -> f64 {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, r: &mut R) -> f64 {
+        use crate::distribution::ziggurat;
+
         ziggurat::sample_exp_1(r) / self.rate
     }
 }

src/distribution/fisher_snedecor.rs

@@ -1,7 +1,6 @@
 use crate::distribution::{Continuous, ContinuousCDF};
 use crate::function::beta;
 use crate::statistics::*;
-use rand::Rng;
 use std::f64;
 
 /// Implements the
@@ -124,8 +123,9 @@ impl std::fmt::Display for FisherSnedecor {
     }
 }
 
+#[cfg(feature = "rand")]
 impl ::rand::distributions::Distribution<f64> for FisherSnedecor {
-    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f64 {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, rng: &mut R) -> f64 {
         (super::gamma::sample_unchecked(rng, self.freedom_1 / 2.0, 0.5) * self.freedom_2)
             / (super::gamma::sample_unchecked(rng, self.freedom_2 / 2.0, 0.5) * self.freedom_1)
     }

src/distribution/gamma.rs

@@ -2,7 +2,6 @@ use crate::distribution::{Continuous, ContinuousCDF};
 use crate::function::gamma;
 use crate::prec;
 use crate::statistics::*;
-use rand::Rng;
 
 /// Implements the [Gamma](https://en.wikipedia.org/wiki/Gamma_distribution)
 /// distribution
@@ -122,8 +121,9 @@ impl std::fmt::Display for Gamma {
     }
 }
 
+#[cfg(feature = "rand")]
 impl ::rand::distributions::Distribution<f64> for Gamma {
-    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f64 {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, rng: &mut R) -> f64 {
         sample_unchecked(rng, self.shape, self.rate)
     }
 }
@@ -400,7 +400,8 @@ impl Continuous<f64, f64> for Gamma {
 ///
 /// ACM Transactions on Mathematical Software, Vol. 26, No. 3, September 2000,
 /// Pages 363-372
-pub fn sample_unchecked<R: Rng + ?Sized>(rng: &mut R, shape: f64, rate: f64) -> f64 {
+#[cfg(feature = "rand")]
+pub fn sample_unchecked<R: ::rand::Rng + ?Sized>(rng: &mut R, shape: f64, rate: f64) -> f64 {
     let mut a = shape;
     let mut afix = 1.0;
     if shape < 1.0 {

src/distribution/geometric.rs

@@ -1,7 +1,5 @@
 use crate::distribution::{Discrete, DiscreteCDF};
 use crate::statistics::*;
-use rand::distributions::OpenClosed01;
-use rand::Rng;
 use std::f64;
 
 /// Implements the
@@ -92,8 +90,11 @@ impl std::fmt::Display for Geometric {
     }
 }
 
+#[cfg(feature = "rand")]
 impl ::rand::distributions::Distribution<f64> for Geometric {
-    fn sample<R: Rng + ?Sized>(&self, r: &mut R) -> f64 {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, r: &mut R) -> f64 {
+        use ::rand::distributions::OpenClosed01;
+
         if ulps_eq!(self.p, 1.0) {
             1.0
         } else {

src/distribution/hypergeometric.rs

@@ -1,7 +1,6 @@
 use crate::distribution::{Discrete, DiscreteCDF};
 use crate::function::factorial;
 use crate::statistics::*;
-use rand::Rng;
 use std::cmp;
 use std::f64;
 
@@ -146,8 +145,9 @@ impl std::fmt::Display for Hypergeometric {
     }
 }
 
+#[cfg(feature = "rand")]
 impl ::rand::distributions::Distribution<f64> for Hypergeometric {
-    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f64 {
+    fn sample<R: ::rand::Rng + ?Sized>(&self, rng: &mut R) -> f64 {
         let mut population = self.population as f64;
         let mut successes = self.successes as f64;
         let mut draws = self.draws;