Figure illustrates the performance of the global optimization of the chemical ordering of a truncated octahedral Au 106 Pt 209 particle using the optimal-exchange BH, the GA with and without optimal-exchange relaxations and simple Monte Carlo (MC) runs. The cumulative success rate for all algorithms has been calculated by running each algorithm 100 times (from different starting points) and evaluating the fraction of runs that have found the (known) global minimum as a function of the number of steps. A step here is defined as the generation and total energy evaluation of one candidate structure.