permute_axes is not correct

[shumpohl]

Using ndarray==0.17.2, the following code

let mut a = Array4::<u8>::zeros((1, 2, 3, 4));
a.permute_axes([3, 0, 1, 2]);
assert_eq!(a.shape(), &[4, 1, 2, 3]);

fails with

assertion `left == right` failed
  left: [4, 3, 2, 1]
 right: [4, 1, 2, 3]

see playground.

[nilgoyette]

>>> a = np.zeros((1, 2, 3, 4))
>>> np.transpose(a, [3, 0, 1, 2]).shape
(4, 1, 2, 3)

Looks like permute_axes is doing a simple transpose, at least with that argument.