Fig 3. Comparison of the dynamic structure approaches.

On the left, we have the previous network-free method. It is simpler to implement, but due to the dynamic structure, each step is significantly more costly in terms of performance. For example, neighborhood relations are dynamic, and therefore, the nesting tree structure needs to be traversed. Our approach (a subset of Fig 2) is on the right. We can utilize a faster flat (i.e., static) model simulator and have a costly but amortizing transformation and optimization process on the rare occasion of a structural change. For example, all relations can be encoded by static indices.