gradient descent to get the cat level if we had a good classifier but we can also we can also optimize the image to make it compatible with the dog label right that's things that if you ever saw deep dream or something like this those models do exactly that they optimize the input image for a particular label and there you can view the entire neural network including the loss function as the energy function so what's another example another example is let's say you have a k-means model and the energy function is simply input a data point