How to implement self-feedback in computational graph?

Computational graph can represent expressions as graphs. For example, a+b can be represented like the above figure. When we consider an expression with self-feedback, how can it be represented as a graph? For example, dv(t)/dt=v(t)+i(t) can be solved as v(t)=v(t-1)f(t)+i(t). It is possible to construct a graph with right-hand side. But, we also have to store the final result to a state variable v. How to handle this issue?

Thank you.

I am not sure to understand what you’re trying to do here. Could you describe what you want to compute?