keras/src/ops/numpy.py/diff
def diff(a, n=1, axis=-1):
    """Calculate the n-th discrete difference along the given axis.

    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]])
    """
    return Diff(n=n, axis=axis)(a)