Comparison of the approximation error and running time.

A comparison of the running time (seconds) and the optimality of the exhaustive search (ES) method, the genetic algorithm (GA) heuristic and the proposed mixed-integer non-linear programming approach (MINLP). “Optimal error" refers to the squared difference between the desired protein value and the optimal circuit value, when the later was found through exhaustive search. “Error" refers to the difference between the optimal error and the heuristic or MINLP error. Since the genetic algorithm solution depends on the initial conditions, “Error Min" and “Error Max" are given.