I have two 3-dimensional arrays called the ‘Feature_Arr’ and ‘Centroids_Arr’.

Each 2d array in the **Feature_Arr** is like:

```
[[-0.16578992, 1.302 , 1. , 1. ],
[ 0. , 0. , 0. , 1. ],
[ 0.00392716, 0.2551 , 1. , 0. ],
[ 0.16186276, 1.1104 , 1. , 1. ]]
```

Each 2d array in the **Centroid_Arr** is like:

```
[[ -4.3150377 , 2.586869 , 0.9627161 ],
[ -1.0964384 , 1.350665 , 0.28387254],
[ -6.1319566 , -2.8796217 , -1.9866784 ],
[ -8.299599 , -7.908891 , -4.6172056 ]]
```

**What I want:**

I’d like to sort each 2D **Feature_Arr** by the ascending of the first column, if there are equal numbers, then sorting by the corresponding numbers from the second column. Then swap the rows of both **Feature_Arr** and **Centroid_Arr** based on the sorting result of the **Feature_Arr** .

**This is what I’ve tried:**

```
import numpy as np
from numba import cuda
@cuda.jit(device=True)
def sort_2d_arrays(feature_arr, centroids_arr):
for i in range(feature_arr.shape[0] - 1):
for j in range(feature_arr.shape[0] - i - 1):
if (feature_arr[j, 0] > feature_arr[j + 1, 0]) or \
(feature_arr[j, 0] == feature_arr[j + 1, 0] and
feature_arr[j, 1] > feature_arr[j + 1, 1]):
for k in range(feature_arr.shape[1]):
temp = feature_arr[j, k]
feature_arr[j, k] = feature_arr[j + 1, k]
feature_arr[j + 1, k] = temp
for k in range(centroids_arr.shape[1]):
temp = centroids_arr[j, k]
centroids_arr[j, k] = centroids_arr[j + 1, k]
centroids_arr[j + 1, k] = temp
@cuda.jit
def sort_features_and_centroids(pharmacophores, centroids):
x = cuda.grid(1)
if x < pharmacophores.shape[0]:
sort_2d_arrays(pharmacophores[x], centroids[x])
```

```
d_features = cuda.to_device(test_features)
d_centroid_coords = cuda.to_device(test_coords)
threadsperblock = (16, 16)
blockspergrid_x = int(np.ceil(test_features.shape[0] / threadsperblock[0]))
blockspergrid_y = int(np.ceil(test_features.shape[1] / threadsperblock[1]))
blockspergrid = (blockspergrid_x, blockspergrid_y)
sort_features_and_centroids[blockspergrid, threadsperblock](d_features, d_centroid_coords)
sorted_features = d_features.copy_to_host()
sorted_centroid_coords = d_centroid_coords.copy_to_host()
```

However, some of 2D arrays were not correctly sorted, for example:

One of the original 2D arrays:

```
[[ 0.14940944 1.5281 1. 1. ]
[ 0. 0. 0. 0. ]
[-0.2631746 0.8732 1. 1. ]
[ 0.1137652 0.6502 0. 1. ]]
```

After being sorted:

```
[[-0.2631746 0. 0. 0. ]
[ 0. 0.8732 1. 1. ]
[-0.2631746 0.8732 1. 1. ]
[ 0.1137652 0.6502 0. 1. ]]
```

one row was copied to another row but no swap. And some other arrays were just incorrectly sorted.

Would greatly appreciate if you could help.