diff --git a/powerboxesrs/src/tiou.rs b/powerboxesrs/src/tiou.rs
index 5505ba0..f9ca6ce 100644
--- a/powerboxesrs/src/tiou.rs
+++ b/powerboxesrs/src/tiou.rs
@@ -1,3 +1,5 @@
+use std::vec;
+
 use ndarray::Array2;
 use num_traits::{Num, ToPrimitive};
 
@@ -41,26 +43,29 @@ where
     let mut tiou_matrix = Array2::<f64>::zeros((num_boxes1, num_boxes2));
     let areas_boxes1 = boxes::box_areas(&boxes1);
     let areas_boxes2 = boxes::box_areas(&boxes2);
-    for (i, a1) in boxes1.outer_iter().enumerate() {
-        let a1_x1 = a1[0];
-        let a1_y1 = a1[1];
-        let a1_x2 = a1[2];
-        let a1_y2 = a1[3];
+    let boxes1_vecs: Vec<(N, N, N, N)> = boxes1
+        .rows()
+        .into_iter()
+        .map(|r| (r[0], r[1], r[2], r[3]))
+        .collect();
+    let boxes2_vecs: Vec<(N, N, N, N)> = boxes2
+        .rows()
+        .into_iter()
+        .map(|r| (r[0], r[1], r[2], r[3]))
+        .collect();
+    for (i, a1) in boxes1_vecs.iter().enumerate() {
+        let (a1_x1, a1_y1, a1_x2, a1_y2) = a1;
 
         let area1 = areas_boxes1[i];
 
-        for (j, a2) in boxes2.outer_iter().enumerate() {
-            let a2_x1 = a2[0];
-            let a2_y1 = a2[1];
-            let a2_x2 = a2[2];
-            let a2_y2 = a2[3];
+        for (j, a2) in boxes2_vecs.iter().enumerate() {
+            let (a2_x1, a2_y1, a2_x2, a2_y2) = a2;
             let area2 = areas_boxes2[j];
-
             // Calculate the enclosing box (C) coordinates
-            let c_x1 = utils::min(a1_x1, a2_x1);
-            let c_y1 = utils::min(a1_y1, a2_y1);
-            let c_x2 = utils::max(a1_x2, a2_x2);
-            let c_y2 = utils::max(a1_y2, a2_y2);
+            let c_x1 = utils::min(*a1_x1, *a2_x1);
+            let c_y1 = utils::min(*a1_y1, *a2_y1);
+            let c_x2 = utils::max(*a1_x2, *a2_x2);
+            let c_y2 = utils::max(*a1_y2, *a2_y2);
             // Calculate the area of the enclosing box (C)
             let c_area = (c_x2 - c_x1) * (c_y2 - c_y1);
             let c_area = c_area.to_f64().unwrap();