Geographical-restraint technique used in the selection and recombination process for the genetic algorithm. (a) A parent is selected (black location) from a random location on the fitness landscape, where a local map is drawn around it. By performing random walks on this local map, more chromosomes are selected as candidates (medium grey) and the fittest one (dark grey) is chosen for the recombination process. (b) A pair of selected chromosomes is chosen for recombination under the control of probability of crossover and mutation. The uniform crossover technique was used for the crossover operation, where only locations indicated on the crossover template were exchanged between the parents. The mutation operator occurred on randomly selected locations on the child chromosomes where their phases were replaced by new phases redrawn from the phase probability distribution.