Bayesian Deep Neural Network

Notes on Bayesian deep neural networks.

I. Goal

We want to construct the posterior distribution p(W D, alpha) and use it to perform prediction.

And we would want to do this using Bayesian rule

So posterior will be approximated by the product of prior p(W alpha) and likelihood P(D W)

II. Likelihood

The likelihood is quite easy to get, usually by probabilistic DNN

For example, for regression problem, we can get this by assuming p(Y X, W) follows a Gaussian distribution N(Y; mean(X,W), variance(X,W))

For classification, we can assume a Categorical distribution