Calculate the n-th discrete difference along the given axis.
tf.keras.ops.diff(
    a, n=1, axis=-1
)
The first difference is given by out[i] = a[i+1] - a[i] along
the given axis, higher differences are calculated by using diff
recursively.
| Args | 
|---|
| a | Input tensor. | 
| n | The number of times values are differenced. Defaults to 1. | 
| axis | Axis to compute discrete difference(s) along.
Defaults to -1.(last axis). | 
| Returns | 
|---|
| Tensor of diagonals. | 
Examples:
from keras.src import ops
x = ops.convert_to_tensor([1, 2, 4, 7, 0])
ops.diff(x)
array([ 1,  2,  3, -7])
ops.diff(x, n=2)
array([  1,   1, -10])
x = ops.convert_to_tensor([[1, 3, 6, 10], [0, 5, 6, 8]])
ops.diff(x)
array([[2, 3, 4],
       [5, 1, 2]])
ops.diff(x, axis=0)
array([[-1,  2,  0, -2]])