Add benchmark for `Min`

Cargo.toml

@@ -20,3 +20,7 @@ streaming-stats = "0.1"
 [[bench]]
 name = "average"
 harness = false
+
+[[bench]]
+name = "min"
+harness = false

benches/min.rs

@@ -0,0 +1,41 @@
+#[macro_use] extern crate bencher;
+extern crate rand;
+
+extern crate average;
+extern crate stats;
+
+use bencher::Bencher;
+
+/// Create a random vector of random floats in [0, 1].
+fn initialize_vec() -> Vec<f64> {
+    use rand::distributions::{Range, IndependentSample};
+    use rand::{XorShiftRng, SeedableRng};
+    let range = Range::new(0.0, 1.0);
+    let n = 1_000_000;
+    let mut values = Vec::with_capacity(n);
+    let mut rng = XorShiftRng::from_seed([1, 2, 3, 4]);
+    for _ in 0..n {
+        values.push(range.ind_sample(&mut rng));
+    }
+    values
+}
+
+fn bench_average(b: &mut Bencher) {
+    let values = initialize_vec();
+    b.iter(|| {
+        let a: average::Min = values.iter().map(|x| *x).collect();
+        a
+    });
+}
+
+fn bench_iter(b: &mut Bencher) {
+    let values = initialize_vec();
+    b.iter(|| {
+        let mut it = values.iter();
+        let init: f64 = *it.next().unwrap();
+        it.fold(init, |a, &b| a.min(b))
+    });
+}
+
+benchmark_group!(benches, bench_average, bench_iter);
+benchmark_main!(benches);