五参数拟合方程，如何计算五个参数，请提供c++源代码

对于五参数拟合方程，一般采用最小二乘法进行求解。下面是一个简单的C++代码示例，使用最小二乘法计算五个参数：

#include <iostream>
#include <vector>
#include <cmath>

using namespace std;

// 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
vector<double> leastSquaresFit(vector<double> x, vector<double> y) {
    int n = x.size();
    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;
    double a = Da / D;
    double b = Db / D;
    double c = Dc / D;
    double d = Dd / D;
    double e = De / D;
    vector<double> params = {a, b, c, d, e};
    return params;
}

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

    // 最小二乘法求解五个参数
    vector<double> params = leastSquaresFit(x, y);

    // 输出结果
    cout << "a = " << params[0] << endl;
    cout << "b = " << params[1] << endl;
    cout << "c = " << params[2] << endl;
    cout << "d = " << params[3] << endl;
    cout << "e = " << params[4] << endl;

    // 根据求解出的五个参数计算函数值
    double x0 = 11.0;
    double y0 = fiveParamEquation(x0, params[0], params[1], params[2], params[3], params[4]);
    cout << "y(" << x0 << ") = " << y0 << endl;

    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。