Effects of initial memory and identical harmony in global optimization using harmony search algorithm

Since the harmony search algorithm searches solution space stochastically, it can find local optima and also global optimum. For the purpose of enhancing the frequency and reaching global optimum, this study introduces two new features that increase the diversity of solutions stored in the harmony memory. The first feature generates initial harmonies more than harmony memory size, and the second limits the number of identical harmonies stored in the harmony memory. After performing extensive simulation, it was shown that limiting the number of identical harmonies in the harmony memory enhanced the solution quality in terms of global optimum frequency and objective function value. It was also shown that generating more initial harmonies did not affect the solution quality significantly. Thus, the technique limiting identical harmonies can be utilized in future applications in order to more optimize the solution quality.