线性拟合C语言算法

最小二乘法拟合一条直线（C语言代码）

#include

#define N 10 //N为要拟合的数据的个数

float X[10] = {1.9,0.8,1.1,0.1,-0.1,4.4,4.6,1.6,5.5,3.4};

float Y[10] = {0.7,-1.0,-0.2,-1.2,-0.1,3.4,0.0,0.8,3.7,2.0};

float K=0; //拟合直线的斜率

float R=0; //拟合直线的截距

float x_sum_average=0; //数组X[N] 个元素求和并求平均值

float y_sum_average=0; //数组Y[N] 个元素求和并求平均值

float x_square_sum=0; //数组X[N] 个个元素的平均值

float x_multiply_y=0; //数组X[N]和Y[N]对应元素的乘机

float Squre_sum(float c[N]) ;

float Sum_Average(float d[N]);

float X_Y_By(float m[N],float n[N]);

float Squre_sum(float c[N]);

void Line_Fit(void);

void Line_Fit(void)

{

x_sum_average= Sum_Average(X);

y_sum_average= Sum_Average(Y);

x_square_sum = Squre_sum(X);

x_multiply_y = X_Y_By(X,Y);

K = ( x_multiply_y - N * x_sum_average * y_sum_average)/( x_square_sum - N * x_sum_average*x_sum_average );

R = y_sum_average - K * x_sum_average;

printf("K = %f\n",K);

printf("R = %f\n",R);

}

float Sum_Average(float d[N])

{

unsigned int i=0;

float z=0;

for(i=0;i

{

z = z + d[i];

}

z = z/N;

return z;

}

float X_Y_By(float m[N],float n[N]) {

unsigned int i=0;

float z=0;

for(i=0;i

{

z = z + m[i]*n[i];

}

return z;

}

float Squre_sum(float c[N])

{

unsigned int i=0;

float z=0;

for(i=0;i

{

z = z + c[i]*c[i];

}

return z;

}

void main(void)

{

Line_Fit();

}