going to take an image or a piece of text mask some parts of it and then ask a system to reconstruct and there is no way to make those predictions exactly and so what we had to have our systems that can deal with the uncertainty in the prediction they can represent the uncertainty of the prediction and it's for that reason to introduce the notion of energy based learning so you can think of it as kind of a weaker form of learning that people are used to which is sort of learning probabilistic models or learning the cities running you know