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-rw-r--r--rand/tests/uniformity.rs67
1 files changed, 67 insertions, 0 deletions
diff --git a/rand/tests/uniformity.rs b/rand/tests/uniformity.rs
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+// 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.
+
+#![cfg(feature = "std")]
+
+#[macro_use]
+extern crate average;
+extern crate rand;
+
+use std as core;
+use rand::FromEntropy;
+use rand::distributions::Distribution;
+use average::Histogram;
+
+const N_BINS: usize = 100;
+const N_SAMPLES: u32 = 1_000_000;
+const TOL: f64 = 1e-3;
+define_histogram!(hist, 100);
+use hist::Histogram as Histogram100;
+
+#[test]
+fn unit_sphere() {
+ const N_DIM: usize = 3;
+ let h = Histogram100::with_const_width(-1., 1.);
+ let mut histograms = [h.clone(), h.clone(), h];
+ let dist = rand::distributions::UnitSphereSurface::new();
+ let mut rng = rand::rngs::SmallRng::from_entropy();
+ for _ in 0..N_SAMPLES {
+ let v = dist.sample(&mut rng);
+ for i in 0..N_DIM {
+ histograms[i].add(v[i]).map_err(
+ |e| { println!("v: {}", v[i]); e }
+ ).unwrap();
+ }
+ }
+ for h in &histograms {
+ let sum: u64 = h.bins().iter().sum();
+ println!("{:?}", h);
+ for &b in h.bins() {
+ let p = (b as f64) / (sum as f64);
+ assert!((p - 1.0 / (N_BINS as f64)).abs() < TOL, "{}", p);
+ }
+ }
+}
+
+#[test]
+fn unit_circle() {
+ use ::std::f64::consts::PI;
+ let mut h = Histogram100::with_const_width(-PI, PI);
+ let dist = rand::distributions::UnitCircle::new();
+ let mut rng = rand::rngs::SmallRng::from_entropy();
+ for _ in 0..N_SAMPLES {
+ let v = dist.sample(&mut rng);
+ h.add(v[0].atan2(v[1])).unwrap();
+ }
+ let sum: u64 = h.bins().iter().sum();
+ println!("{:?}", h);
+ for &b in h.bins() {
+ let p = (b as f64) / (sum as f64);
+ assert!((p - 1.0 / (N_BINS as f64)).abs() < TOL, "{}", p);
+ }
+}