of a particular class because you don't you you don't want to make take a particular class and see the perturbation direction for that class you take a distribution of classes and you take something a distance metric between your unperturbed data point and your perturb data point in trying to figure out the direction that maximizes this scale and it turns out if you linearized scale term you can actually solve for this direction are using power iteration and once you get the direction and you can make sure that you info