五参数拟合算法，如何反求五个参数，请提供c语言源代码

五参数拟合算法是一种基于最小二乘法的拟合算法，可以用于拟合某些具有五个自由参数的非线性函数。反求五个参数的过程即为使用拟合算法计算出五个最优参数的过程。下面是一个简单的C语言源代码示例，使用最小二乘法反求五个参数：

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

// 五参数拟合方程
double fiveParamEquation(double x, double a, double b, double c, double d, double e) {
    return a * pow(x, 4) + b * pow(x, 3) + c * pow(x, 2) + d * x + e;
}

// 最小二乘法求解五参数拟合方程
void leastSquaresFit(double x[], double y[], int n, double *a, double *b, double *c, double *d, double *e) {
    double sum_x = 0.0, sum_x2 = 0.0, sum_x3 = 0.0, sum_x4 = 0.0, sum_y = 0.0, sum_xy = 0.0, sum_x2y = 0.0, sum_x3y = 0.0;
    for (int i = 0; i < n; i++) {
        sum_x += x[i];
        sum_x2 += pow(x[i], 2);
        sum_x3 += pow(x[i], 3);
        sum_x4 += pow(x[i], 4);
        sum_y += y[i];
        sum_xy += x[i] * y[i];
        sum_x2y += pow(x[i], 2) * y[i];
        sum_x3y += pow(x[i], 3) * y[i];
    }
    double D = n * sum_x2 * sum_x4 + 2 * sum_x * sum_x3 * sum_x2 - n * pow(sum_x3, 2) - pow(sum_x2, 2) * n - pow(sum_x, 2) * sum_x4 + pow(sum_x2, 2);
    double Da = sum_y * sum_x2 * sum_x4 + sum_x * sum_x3y * sum_x2 + sum_x3 * sum_x2y * n - sum_x3 * sum_y * sum_x2 - sum_x * sum_x2y * sum_x4 - sum_x2 * sum_x3y * n;
    double Db = sum_x3 * sum_y * sum_x4 + sum_x * sum_x2y * sum_x4 + sum_x2 * sum_x3y * sum_x2 - sum_x2y * sum_x4 * n - sum_x2 * sum_y * sum_x3 - sum_x * sum_x3y * sum_x2;
    double Dc = sum_x2 * sum_y * sum_x4 + sum_x * sum_x3y * sum_x2 + sum_x3 * sum_x2y * sum_x3 - sum_x3 * sum_y * sum_x2 - sum_x * sum_x2y * sum_x4 - sum_x2 * sum_x2y * n;
    double Dd = sum_x2 * sum_x3 * sum_y + sum_x2y * sum_x4 * n + sum_x * sum_x2 * sum_x3y - sum_x3 * sum_x2y * sum_x2 - sum_x * sum_x2y * sum_x3 - sum_x2 * sum_x4 * sum_y;
    double De = sum_x2 * sum_x3y * sum_x4 + sum_x2y * sum_x3 * sum_x2 + sum_x * sum_x2y * sum_x3y - sum_x3 * sum_x2y * sum_x2 - sum_x * sum_x3y * sum_x4 - sum_x2 * sum_x2y * sum_x3;
    *a = Da / D;
    *b = Db / D;
    *c = Dc / D;
    *d = Dd / D;
    *e = De / D;
}

int main() {
    // 生成随机数据
    double x[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    double y[] = {2.4, 3.5, 4.6, 5.7, 6.8, 7.9, 9.0, 10.1, 11.2, 12.3};
    int n = 10;

    // 最小二乘法求解五个参数
    double a, b, c, d, e;
    leastSquaresFit(x, y, n, &a, &b, &c, &d, &e);

    // 输出结果
    printf("a = %f\n", a);
    printf("b = %f\n", b);
    printf("c = %f\n", c);
    printf("d = %f\n", d);
    printf("e = %f\n", e);

    // 根据求解出的五个参数计算函数值
    double x0 = 11.0;
    double y0 = fiveParamEquation(x0, a, b, c, d, e);
    printf("y(%f) = %f\n", x0, y0);

    return 0;
}

上述代码中，`fiveParamEquation`函数是五参数拟合方程的实现，`leastSquaresFit`函数是使用最小二乘法求解五个参数的函数，`main`函数中生成了一组随机数据，然后调用`leastSquaresFit`函数求解五个参数，并输出结果。最后，根据求解出的五个参数计算了一个新的函数值。