MOP4 function from Van Valedhuizen's test suite based on Kursawe.
F. Kursawe, "A variant of evolution strategies for vector optimization," in Lecture Notes in Computer Science, H.-P. Schwefel and R. Maenner, Eds. Berlin, Germany: Springer-Verlag, 1991, vol. 496, Proc. Parallel Problem Solving From Nature. 1st Workshop, PPSN I, pp. 193-197.