60 lines
2.2 KiB
C++
60 lines
2.2 KiB
C++
#include "LeastSquarePolynomial.h"
|
|
|
|
// form of [ y = a1*x + a2 ]
|
|
void CalcEquation2(float afA[2], const float afX[2], const float afY[2])
|
|
{
|
|
afA[0] = (afY[0]-afY[1])/(afX[0]-afX[1]);
|
|
afA[1] = afY[0] - afA[0]*afX[0];
|
|
}
|
|
|
|
// form of [ y = a1*x*x + a2*x + a3 ]
|
|
void CalcEquation3(float afA[3], const float afX[3], const float afY[3])
|
|
{
|
|
//afY[0] = afA[0]*afX[0]*afX[0] + afA[1]*afX[0] + afA[2];
|
|
//afY[1] = afA[0]*afX[1]*afX[1] + afA[1]*afX[1] + afA[2];
|
|
|
|
//(afY[0]-afY[1]) = afA[0]*(afX[0]*afX[0]-afX[1]*afX[1]) + afA[1]*(afX[0]-afX[1]);
|
|
//(afY[0]-afY[2]) = afA[0]*(afX[0]*afX[0]-afX[2]*afX[2]) + afA[1]*(afX[0]-afX[2]);
|
|
|
|
//(afY[0]-afY[1])/(afX[0]-afX[1]) = afA[0]*(afX[0]*afX[0]-afX[1]*afX[1])/(afX[0]-afX[1]) + afA[1];
|
|
//(afY[0]-afY[2])/(afX[0]-afX[2]) = afA[0]*(afX[0]*afX[0]-afX[2]*afX[2])/(afX[0]-afX[2]) + afA[2];
|
|
|
|
const float afNewX[2] = {
|
|
(afX[0]*afX[0]-afX[1]*afX[1])/(afX[0]-afX[1]),
|
|
(afX[0]*afX[0]-afX[2]*afX[2])/(afX[0]-afX[2])
|
|
};
|
|
|
|
const float afNewY[2] = {
|
|
(afY[0]-afY[1])/(afX[0]-afX[1]),
|
|
(afY[0]-afY[2])/(afX[0]-afX[2])
|
|
};
|
|
|
|
CalcEquation2(afA, afNewX, afNewY);
|
|
afA[2] = afY[0] - afA[0]*afX[0]*afX[0] - afA[1]*afX[0];
|
|
}
|
|
|
|
// form of [ y = a1*x*x*x + a2*x*x + a3*x + a4 ]
|
|
void CalcEquation4(float afA[4], const float afX[4], const float afY[4])
|
|
{
|
|
//afY[0] = afA[0]*afX[0]*afX[0]*afX[0] + afA[1]*afX[0]*afX[0] + afA[2]*afX[0] + afA[3];
|
|
//afY[1] = afA[0]*afX[1]*afX[1]*afX[1] + afA[1]*afX[1]*afX[1] + afA[2]*afX[1] + afA[3];
|
|
|
|
//(afY[0]-afY[0]) = afA[0]*(afX[0]*afX[0]*afX[0]-afX[1]*afX[1]*afX[1]) + afA[1]*(afX[0]*afX[0]-afX[1]*afX[1]) + afA[2]*(afX[0]-afX[1]);
|
|
|
|
//(afY[0]-afY[0])/(afX[0]-afX[1]) = afA[0]*(afX[0]*afX[0]*afX[0]-afX[1]*afX[1]*afX[1])/(afX[0]-afX[1]) + afA[1]*(afX[0]*afX[0]-afX[1]*afX[1])/(afX[0]-afX[1]) + afA[2];
|
|
|
|
const float afNewX[3] = {
|
|
(afX[0]*afX[0]*afX[0]-afX[1]*afX[1]*afX[1])/(afX[0]-afX[1]),
|
|
(afX[0]*afX[0]*afX[0]-afX[2]*afX[2]*afX[2])/(afX[0]-afX[2]),
|
|
(afX[0]*afX[0]*afX[0]-afX[3]*afX[3]*afX[3])/(afX[0]-afX[3])
|
|
};
|
|
|
|
const float afNewY[3] = {
|
|
(afY[0]-afY[0])/(afX[0]-afX[1]),
|
|
(afY[0]-afY[0])/(afX[0]-afX[2]),
|
|
(afY[0]-afY[0])/(afX[0]-afX[3])
|
|
};
|
|
|
|
CalcEquation3(afA, afNewX, afNewY);
|
|
afA[3] = afY[0] - afA[0]*afX[0]*afX[0]*afX[0] - afA[1]*afX[0]*afX[0] - afA[2]*afX[0];
|
|
} |