改进的最大最小蚂蚁系统，把信息素更新分为3个阶段，每个阶段信息素的浓度数量级相差很大，更加相差的数量级，调整更新的信息素-Improved maximum and minimum ant system, the pheromone update into three phases, each pheromone concentration very different order of magnitude more difference of magnitude, adjust pheromon