In my program, there is no random number. However, when I repeat running it, the optimization result is different and sometimes it said that “Automatic differentiation for gradient failed”. I am very confused, because it is exactly the same program without any random number. Whether I must write down the formula of gradient then I will generate the same result?
Besides, I also want to know a warning “Gradient and Hessian already defined”. Does this warning matter?
Thanks for your help and hope for response!