text1.c

最小二乘法拟合用在嵌入式系统的代码,单片机上可以测试过

/*拟合直线方程为y = ax +b*/
#include <stdio.h>
#include <reg51f.h>
#define N_MAX  20    //拟合折线的总数据个数
#define N_TOTAL 15   //实际需拟合折线的总数据个数
#define N_SECTION 3  //一段拟合的数据个数
#define SECTION 5//段数
unsigned int x[N_MAX] = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
unsigned int y[N_MAX] = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15}; //拟合折线的数据
unsigned int dx[N_SECTION],dy[N_SECTION]; //一段拟合的数据
long k[2][3],m1,m2,m0;
int i = 0,j = 0;
//求∑Ai*Bi
long fsum(unsigned int *a,unsigned int *b,int c)
{
        long sum=0;
        for(i=0;i < c;i++)
                sum+=a[i]*b[i];
        return sum; 
}

//求矩阵
long fmatrix(unsigned char m,unsigned char n)
{
        long matrix;
        matrix=k[0][m]*k[1][n]-k[0][n]*k[1][m];
        return matrix;
}
//求折线参数
void get_value(float *pa,float *pb)
{
	long n_section_temp;
        unsigned int mi[N_SECTION] = {1,1,1};                //大小为1的数列，矩阵求和时匹配使
      for(i=0;i < N_SECTION;i++)
		{
               mi[i]=1;
		}
	n_section_temp = (long) N_SECTION;
//求线性方程系数
        k[0][0]=fsum(dx,dx,n_section_temp);
        k[0][1]=fsum(dx,mi,n_section_temp);
        k[0][2]=-fsum(dx,dy,n_section_temp);
        k[1][0]=fsum(dx,mi,n_section_temp);
        k[1][1]=n_section_temp;
        k[1][2]=-fsum(mi,dy,n_section_temp);
//输出线性方程系数
        m0=fmatrix(0,1);
        m1=fmatrix(1,2);
        m2=fmatrix(2,0);

 //       if(m0==0) return ;
//	else
//	{	 
	*pb = (float) (m2/m0);
	*pa = (float) (m1/m0);
//	}
}/*
void get_value(float *pa,float *pb)
{
*pa = 9;
*pb = 8;
}*/
//求最大值
float get_max(float * pp,int pp_size)
{
	float max_temp = *pp;
	for(i = 1;i<pp_size;i++)
	{
	if(max_temp<*(pp+i))
	{
	max_temp = *(pp+i);
	}
	}
	return max_temp;
}
main()
{
	float aBuffer[SECTION],bBuffer[SECTION];
	TI = 1;
	printf("HELLO");
	TI = 0;
	i = 1;
	for(i = 0;i<2;i++)
	{
		for(j = 0;j<N_SECTION;j++)
		{
		dx[j] = x[i*N_SECTION+j];
		dy[j] = y[i*N_SECTION+j];
		}
		get_value(aBuffer+i,bBuffer+i);
	}
	for(i = 0;i<SECTION;i++)
	{
		TI = 1;
		printf("a = %lf,b = %lf",*(aBuffer+i),*(bBuffer+i));
		TI = 0;
	}
/*	dx[0] = 1;dx[1] = 2;dx[2] = 3;
	dy[0] = 4;dy[1] = 7;dy[2] = 10;
	get_value(aBuffer,bBuffer);
	TI = 1;
	printf("a = %lf,b = %lf",*aBuffer,*bBuffer);
	TI = 0;*/
	while(1);
}