最小二乘法擬合一條直線（C語言代碼）

ID:90014 · 發(fā)表于 2015-9-15 14:58

#include<stdio.h>
#define N10 //N為要擬合的數(shù)據(jù)的個(gè)數(shù)
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};
floatK=0; //擬合直線的斜率
floatR=0; //擬合直線的截距
float x_sum_average=0; //數(shù)組 X[N] 個(gè)元素求和并求平均值
float y_sum_average=0; //數(shù)組 Y[N] 個(gè)元素求和并求平均值
float x_square_sum=0; //數(shù)組 X[N] 個(gè)個(gè)元素的平均值
float x_multiply_y=0; //數(shù)組 X[N]和Y[N]對應(yīng)元素的乘機(jī)
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<N;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<N;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<N;i++)
{
z = z + c[i]*c[i];
}
return z;
}
void main(void)
{
Line_Fit();
}

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