本文共 918 字,大约阅读时间需要 3 分钟。
斯特芬森加速迭代法(Steffensen)/埃特金方法(Aitken)较迭代法的优点:1.迭代法收敛-->加速收敛2.迭代法不收敛-->收敛
/* 方程f(x) = x^3 - 3 * x - 1 = 0有三个实根x1 = 1.8793, x2 = -0.34727, x3 = -1.53209. 本实验采用下面两种计算格式,求的根x1或x2或x3.*/#include#include double f1(double x){ //迭代函数f1(x) return (3.0 * x + 1) / (x * x);}double f2(double x){ //迭代函数f2(x) return 1.0 / (x * x - 3);}double Steffensen(double x){ return x -((f1(x) - x) * (f1(x) - x) / (f1(f1(x)) - 2.0 * f1(x) + x));}int main(){ double x1, d; double x0 = 0.5; //迭代初值 double eps = 0.0001; //求解精度 int k = 0; //迭代次数 do{ k++; x1 = Steffensen(x0); ///迭代函数 printf("%d %f\n", k, x1); d = fabs(x1 - x0); x0 = x1; }while(d >= eps); printf("the root of f(x) = 0 is x = %f, k = %d\n", x1, k); return 0;}
f1(x):
f1(x)Steffensen加速后: f2(x): f2(x)Steffensen加速后: