Abstract
Within memetic computing frameworks, the structure as well as a correct choice of memes are important elements that drive successful optimization algorithms. This paper studies variations of a promising yet simple search operator, the S Algorithm, which can easily be integrated within a memetic framework to improve candidate solutions. S is a single-solution optimizer that iteratively perturbs variables and conditionally evaluates solutions along the axes. The first S variant, namely S2, unconditionally evaluates solutions in both directions while S3 maintains D uncorrelated step sizes that are either expanded in the direction of improving fitness or else redirected and contracted. Numerical results from the CEC2010 and CEC2014 benchmarks show that the variants outperform S in terms of the number of function evaluations for a given fitness value and, further, that S3 outperforms S in terms of final fitness against a wide range of problems and dimensionality.