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最小二乘法直线拟合

最⼩⼆乘法直线拟合/

功能描述：利⽤最⼩⼆乘法求斜率 //

xyTopX -- 截距 //

//⽅法1：

xyTopY -- 斜率 //

湖南卫视百科全说nCount -- 点数 //

void Min2Method(double &xyTopY, double &xyTopX, int X[], int Y[], int nCount) {

int i;

double SumX, SumY, SumXY, SumX2;

SumX = 0;

SumX2 = 0;

for( i=0; i<nCount; i++)

{

SumX += X[i];

SumX2 += (X[i]*X[i]);

}

污染源自动监控设施现场监督检查办法SumY = 0;

for( i=0; i<nCount; i++)

{

SumY += Y[i];

}

SumXY = 0;

for( i=0; i<nCount; i++)

{

SumXY += ( X[i]* Y[i]);

}

xyTopX = ( (SumX2*SumY - SumX*SumXY) / (nCount*SumX2 - SumX * SumX)); xyTopY = ( (nCount*SumXY - SumX*SumY) / (nCount*SumX2 - SumX * SumX)); }

void CTmfcDlg::OnButton2()

{

int x [100]; int y[100];

Graphics graphics(this->m_hWnd); Pen pen(Color(255, 0, 0, 255));

太乐唱录机for( int i = 0 ; i<100; i++)

{

x[i] = i ; y[i] = i ;

if ( i%3 == 0 )lancet

{

x[i] = i +10 ; y[i] = i ;

}

graphics.DrawLine(&pen, Point(x[i],y[i]),Point(x[i],y[i]+1)) ;

}

double k, b;

Min2Method(k,b, x, y, 100 ); showmessage( k, b );

graphics.DrawLine(&pen, 0, b, 100, k*100+b ); // Y=kX+b;

}

//⽅法2： (这是⽹上最多的直线拟合函数)

class CFoldPoint

{

public:

CFoldPoint( double x, double y)

{

X = x;

Y = y;

}

double X;

double Y;

};

typedef CTypedPtrList<CPtrList,CFoldPoint*> CFoldPointList; CFoldPointList FoldList;

BOOL CalculateLineKB(CFoldPointList *m_FoldList,double &k,double &b) {

//最⼩⼆乘法直线拟合

//m_FoldList为关键点(x,y)的链表

//拟合直线⽅程(Y=kX+b)

if(m_FoldList==NULL) return FALSE;

long lCount=m_FoldList->GetCount();

if(lCount<2)return FALSE;

CFoldPoint *pFold;

double mX,mY,mXX,mXY,n;

mX=mY=mXX=mXY=0;

n=lCount;

POSITION pos=m_FoldList->GetHeadPosition();

while(pos != NULL)

{

pFold=m_FoldList->GetNext(pos);

mX+=pFold->X;

mY+=pFold->Y;

mXX+=pFold->X*pFold->X;

mXY+=pFold->X*pFold->Y;

}

if(mX*mX-mXX*n==0)return FALSE;

k=(mY*mX-mXY*n)/(mX*mX-mXX*n);

b=(mY-mX*k)/n;

return TRUE;

}

void CTmfcDlg::OnButton3()

{

// TODO: Add your control notification handler code here

int x [100]; int y[100];

Graphics graphics(this->m_hWnd); Pen pen(Color(255, 0, 0, 255));

for( int i = 0 ; i<100; i++)

{

if (i%2 == 0)

{ continue;

x[i] = i +22 ;

y[i] = i;

FoldList.AddTail( &CFoldPoint(x[i],y[i]) );

}

else

{

x[i] = i -22;

y[i] = i;

FoldList.AddTail( &CFoldPoint(x[i],y[i]) );

}

吹破气球

}

double k, b ;

CalculateLineKB( &FoldList, k, b);

showmessage( k, b );

graphics.DrawLine(&pen, 0, b, 100, k*100+b ); }

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