Solved by 111367 in post #6 
              
              
                Thanks AlphaBetaGamma96. I’ve find a solution which I can continue to train it when using torch1.8.1+cu111. The following is my solution after declaring these 2 variables to access the Constraint(). 
class TanhBijector(torch.distributions.Transform):
    def __init__(self):
        super().__init__(…