TimSal

There are currently many excellent frameworks to choose from: TensorFlow, Theano, Torch, MXNet are all great. The comparative advantage of TensorFlow is mostly its support in the community (e.g. most stars on GitHub, most new projects being developed, etc).

The VAE code and the semi-supervised part of the GAN code build on code that was developed about half a year ago, when Tensorflow was less developed and was lacking in speed and functionality compared to Theano. It has since caught up and most new projects at OpenAI are now done using Tensorflow, which is what we used for the newer additions.