使用levmar的L-M算法拟合曲线

本文所要你拟合的曲线公式:

未知参数:Pi

所求参数数目m=4

已知的点数目n=7

初始的参数设定 p[m] = { 1,1,1,1 }

X[i]设定为y: x[n] = {0,1,2,2,3,4,2};

Data是已知点的x:data[7] = {0,1,2,3,3,4,10};

其他保留为默认。

目标函数:

void ros(double* p, double* x, int m, int n, void* data){
    LVTYPE* data1 = (LVTYPE*)data;
    register int i;
    for (i = 0; i < n; i++){
        x[i] =(p[0]+p[1] * data1[i]+p[2]*data1[i]*data1[i]+p[3]*data1[i]*data1[i]*data1[i]);

    }
}

雅可比函数:

void jacros(double* p, double *jac, int m, int n, void* data){
    LVTYPE* data1 = (LVTYPE*)data;
    register int i, j;
    for (i = 0, j = 0; i < n; i++){
        jac[j++] = 1;
        jac[j++] = data1[i];
        jac[j++] = data1[i]*2;
        jac[j++] = data1[i] * data1[i] * data1[i] * 3;
    }
}

调用:

int ret = dlevmar_der(ros, jacros, p, x, m, n, 10000, NULL, info, NULL, NULL, (void*)data);

结果:

原文地址:https://www.cnblogs.com/jiafenggang/p/5008044.html