I can&#x27;t speak for TensorFlow, but I&#x27;ve personally found Theano to be the most easily extensible among the other widespread deep&#x2F;reinforcement&#x2F;gradient learning libraries (Caffe, Torch, Keras, Chainer).  There does seem to be a performance hit between Theano and Caffe&#x2F;Torch, but it&#x27;s great for prototyping.