descent on differentiable functions in your I mean not specifically perhaps but more even looking into the future what's your thought about that space of approaches yeah so I tend to think of machine learning algorithms as decomposed into really three different pieces there's the model which can be something like a neural nut or a Bolton machine or a recurrent model and I basically just described how do you take data and how do you take parameters and you know what function do you use to make a prediction given the