linefit.cpp

根据最小二乘法由一组点拟合一条直线

//---------------------------------------------------------------------------


#pragma hdrstop

#include "LineFit.h"
#include <assert.h>

//---------------------------------------------------------------------------

#pragma package(smart_init)

/*LineFit::LineFit(Tpoint l_point[],int n_point)
{
        //TODO: Add your source code here
        assert(n_point);
        double av_x,av_y;
	double l_xx,l_yy,l_xy;
	av_x = 0;
	av_y = 0;
	l_xx = 0;
	l_yy = 0;
	l_xy = 0;
	for(int i = 0;i<n_point;i++)
        {
                av_x += l_point[i].x/n_point;
                av_y += l_point[i].y/n_point;
        }
	for(int i = 0;i<n_point;i++)
        {
                l_xx += (l_point[i].x - av_x)*(l_point[i].x - av_x);
                l_yy += (l_point[i].y - av_y)*(l_point[i].y - av_y);
                l_xy += (l_point[i].x - av_x)*(l_point[i].y - av_y);
        }
        a = l_xy/l_xx;
        b = av_y - l_xy*av_x/l_xx;
        r = l_xy/sqrt(l_xx*l_yy);
}

double __fastcall LineFit::get_x(double y)
{
        //TODO: Add your source code here
        assert(a);
        double x;
        x=(y-b)/a;
        return x;
}

double __fastcall LineFit::get_y(double x)
{
        //TODO: Add your source code here
        double y;
        y=a*x+b;
        return y;
}  */