fix use of approx in test_axis_chunks_iter_mut

Author: David Yamnitsky

tests/par_rayon.rs

@@ -73,7 +73,9 @@ fn test_axis_chunks_iter() {
 }
 
 #[test]
+#[cfg(feature = "approx")]
 fn test_axis_chunks_iter_mut() {
+    use approx::assert_abs_diff_eq;
     let mut a = Array::linspace(0., 1.0f64, M * N)
         .into_shape((M, N))
         .unwrap();
@@ -82,5 +84,5 @@ fn test_axis_chunks_iter_mut() {
         .into_par_iter()
         .for_each(|mut v| v.mapv_inplace(|x| x.exp()));
     println!("{:?}", a.slice(s![..10, ..5]));
-    assert!(a.all_close(&b, 0.001));
+    assert_abs_diff_eq!(a, b, epsilon = 0.001);
 }