I am not really familiar with TensorFlow or PyTorch, hence I can’t say anything about which one should be a good replacement for Theano. But I have a question. Could autograd be and alternative to Theano? One of the pain-points for users of PyMC3 is having to deal with Theano (erros, scan, integrating external functions, etc), using autograd should reduce these problems because everything could be written using just NumPy. Numba could also help to accelerate things if needed.