Add a example benchmark for zipped iteration.

benches/iter.rs

@@ -0,0 +1,85 @@
+#![feature(test)]
+#![allow(deprecated)]
+
+extern crate test;
+use test::{black_box, Bencher};
+
+use ndarray::Zip;
+use numpy::{npyiter::NpyMultiIterBuilder, PyArray};
+use pyo3::Python;
+
+fn numpy_iter(bencher: &mut Bencher, size: usize) {
+    Python::with_gil(|py| {
+        let x = PyArray::<f64, _>::zeros(py, size, false);
+        let y = PyArray::<f64, _>::zeros(py, size, false);
+        let z = PyArray::<f64, _>::zeros(py, size, false);
+
+        let x = x.readonly();
+        let y = y.readonly();
+        let mut z = z.readwrite();
+
+        bencher.iter(|| {
+            let iter = NpyMultiIterBuilder::new()
+                .add_readonly(black_box(&x))
+                .add_readonly(black_box(&y))
+                .add_readwrite(black_box(&mut z))
+                .build()
+                .unwrap();
+
+            for (x, y, z) in iter {
+                *z = x + y;
+            }
+        });
+    });
+}
+
+#[bench]
+fn numpy_iter_small(bencher: &mut Bencher) {
+    numpy_iter(bencher, 2_usize.pow(5));
+}
+
+#[bench]
+fn numpy_iter_medium(bencher: &mut Bencher) {
+    numpy_iter(bencher, 2_usize.pow(10));
+}
+
+#[bench]
+fn numpy_iter_large(bencher: &mut Bencher) {
+    numpy_iter(bencher, 2_usize.pow(15));
+}
+
+fn ndarray_iter(bencher: &mut Bencher, size: usize) {
+    Python::with_gil(|py| {
+        let x = PyArray::<f64, _>::zeros(py, size, false);
+        let y = PyArray::<f64, _>::zeros(py, size, false);
+        let z = PyArray::<f64, _>::zeros(py, size, false);
+
+        let x = x.readonly();
+        let y = y.readonly();
+        let mut z = z.readwrite();
+
+        bencher.iter(|| {
+            Zip::from(black_box(x.as_array()))
+                .and(black_box(y.as_array()))
+                .and(black_box(z.as_array_mut()))
+                .for_each(|x, y, z| {
+                    *z = x + y;
+                });
+        });
+    });
+}
+
+#[bench]
+fn ndarray_iter_small(bencher: &mut Bencher) {
+    ndarray_iter(bencher, 2_usize.pow(5));
+}
+
+#[bench]
+fn ndarray_iter_medium(bencher: &mut Bencher) {
+    ndarray_iter(bencher, 2_usize.pow(10));
+}
+
+#[bench]
+fn ndarray_iter_large(bencher: &mut Bencher) {
+    ndarray_iter(bencher, 2_usize.pow(15));
+}