From 647b6d2ecb0fcbbabcdfae625667bb9f3d558cad Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Thu, 28 May 2020 14:50:03 -0400
Subject: benches: Add criterion benchmarks

---
 benches/benches.rs | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 benches/benches.rs

(limited to 'benches')

diff --git a/benches/benches.rs b/benches/benches.rs
new file mode 100644
index 0000000..a43e731
--- /dev/null
+++ b/benches/benches.rs
@@ -0,0 +1,64 @@
+//! Benchmark for various NearestNeighbors implementations.
+
+use acap::euclid::Euclidean;
+use acap::exhaustive::ExhaustiveSearch;
+use acap::NearestNeighbors;
+
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+
+use std::iter::FromIterator;
+
+type Point = Euclidean<[f32; 3]>;
+
+/// Generates a spiral used as the benchmark data set.
+fn spiral() -> Vec<Point> {
+    let mut points = Vec::new();
+
+    let size = 1000;
+    let turns = 10.0;
+    for i in 0..size {
+        let y = 2.0 * (i as f32) / (size as f32) - 1.0;
+        let m = (1.0 - y * y).sqrt();
+        let theta = turns * y * std::f32::consts::PI;
+        let (sin, cos) = theta.sin_cos();
+        let x = m * cos * cos;
+        let z = m * sin * cos;
+        points.push(Euclidean([x, y, z]));
+    }
+
+    points
+}
+
+fn bench_from_iter(c: &mut Criterion) {
+    let points = black_box(spiral());
+
+    let mut group = c.benchmark_group("from_iter");
+    group.bench_function("ExhaustiveSearch", |b| b.iter(|| ExhaustiveSearch::from_iter(points.clone())));
+    group.finish();
+}
+
+fn bench_nearest_neighbors(c: &mut Criterion) {
+    let points = black_box(spiral());
+    let target = black_box(Euclidean([0.0, 0.0, 0.0]));
+
+    let exhaustive = ExhaustiveSearch::from_iter(points.clone());
+
+    let mut nearest = c.benchmark_group("NearestNeighbors::nearest");
+    nearest.bench_function("ExhaustiveSearch", |b| b.iter(|| exhaustive.nearest(&target)));
+    nearest.finish();
+
+    let mut nearest_within = c.benchmark_group("NearestNeighbors::nearest_within");
+    nearest_within.bench_function("ExhaustiveSearch", |b| b.iter(|| exhaustive.nearest_within(&target, 0.1)));
+    nearest_within.finish();
+
+    let mut k_nearest = c.benchmark_group("NearestNeighbors::k_nearest");
+    k_nearest.bench_function("ExhaustiveSearch", |b| b.iter(|| exhaustive.k_nearest(&target, 3)));
+    k_nearest.finish();
+
+    let mut k_nearest_within = c.benchmark_group("NearestNeighbors::k_nearest_within");
+    k_nearest_within.bench_function("ExhaustiveSearch", |b| b.iter(|| exhaustive.k_nearest_within(&target, 3, 0.1)));
+    k_nearest_within.finish();
+}
+
+criterion_group!(benches, bench_from_iter, bench_nearest_neighbors);
+criterion_main!(benches);
-- 
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