Implements the "/arith" (arithmetic) recombination for the ExpDE framework
recombination_arith(X, M, ...)population matrix (original)
population matrix (mutated)
optional parameters (unused)
Matrix U containing the recombined population
F. Herrera, M. Lozano, A. M. Sanchez, "A taxonomy for the crossover operator for real-coded genetic algorithms: an experimental study", International Journal of Intelligent Systems 18(3) 309-338, 2003.