Black box alpha divergence minimization

Thank you for your help @dustin and would like to add that the team is doing a great job on Edward :slight_smile:

I am attaching my first working version of the code here as I believe it works in the way I would want it to.

I also used jbr’s Renyi Divergence vae example and made an extremely similar version here.

The ELBO I have used is based on the reparameterized BB-alpha energy in this paper in section 4.

Could someone please check the logic of my code?

To test that the code works properly, alpha = 0 should perform similarly to KLqp and alpha = 1 should perform similar to KLpq. An arbitrary value of 0.5 was chosen in my example.