here's here's a point X and we turn it into f of X this is just what a flow does and so we can define this distribution here so this distribution on the left this like this this ellipsoid and we're going to define it to be a standard normal where the mean is just f of X it's just the length but we give it this covariance matrix which is Sigma squared is just a small number like 0.0001 or something like that just some hyper parameter to this algorithm times the Jacobian times Jacobian transpose of the flow model and and so