pso粒子群优化算法，所有的粒子都有一个由被优化的函数决定的适应值，每个粒子还有一个速度决定他们运动的方向和距离，然后粒子就追随当前的最优粒子在解空间中搜索-Pso particle swarm optimization algorithm, all particles have an optimized value determined by the function, each particle also has a speed to determine their movement dir