“…There is quite a bit of recent work on understanding efficient algorithms as well as fundamental limitations for this problem. For example, fundamental limitations in terms of unavoidably large control energy have been studied in [18,17,26,11] among others. Algorithms for actuator placement, in either the fixed or time-varying regime, based on randomized sampling [3,10,19,6], convex relaxation [24,22], or greedy methods [25,4,13,20,27,21] were studied in recent works.…”