迭代法也称辗转法，是一种不断用变量的旧值递推新值的过程，跟迭代法相对应的是直接法，即一次性解决问题。迭代法又分为精确迭代和近似迭代。(Iteration method, also known as the toss method, is a constant use of the old value of the value of the process of recursive new value, with the iterative method corresponds to the direct method, that is, one-time to solve the problem. Iteration method is divided into exact iteration and approximate iteration.)