def METHOD_NAME(self, other):
    r"""
    Calculate the separation to another pixel coordinate.
    This is the two-dimensional Cartesian separation :math:`d` where
    .. math::
        d = \sqrt{(x_1 - x_2) ^ 2 + (y_1 - y_2) ^ 2}
    Parameters
    ----------
    other : `PixCoord`
        The other pixel coordinate.
    Returns
    -------
    separation : `numpy.array`
        The separation in pixels.
    """
    dx = other.x - self.x
    dy = other.y - self.y
    return np.hypot(dx, dy)