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ovince
Yugoslavia
Posts |
 Posted - 11/20/2006 : 07:30:11 AM
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hi,
Using a fitpoly() method, I got the coefficents of 2nd order polynom
Curve crv(x,y);
double coeff[2];
bool bRet=fitpoly(crv, 1, coeff);
Can I use them to overplot the polynom over the (already existing) graph and how?
Thanks
Oliver |
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Mike Buess
USA
3037 Posts |
Posted - 11/20/2006 : 08:24:10 AM
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Hi Oliver,
Create a new column in the wks containing x and y. Fill column with values of the polynomial. Plot column in existing layer.
int colNum = wks.AddCol();
Dataset dx(wks,0); // X dataset
Dataset dy(wks,colNum); // Y dataset
for(int i=0; i<dx.GetSize(); i++)
{
dy[i] = coeff[0] + coeff[1]*dx[i];
}
Curve crv(wks,colNum);
gl.AddPlot(crv,IDM_PLOT_LINE); // gl is existing graph layer
Mike Buess
Origin WebRing Member |
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ovince
Yugoslavia
Posts |
Posted - 11/20/2006 : 09:35:30 AM
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thanks Mike
something strange is happening in the for loop
int colNum = wks.AddCol();
Dataset dx(wks,0); // X dataset
Dataset dy(wks,colNum); // Y dataset
for(int i=0; i<dx.GetSize(); i++)
{
printf("%f\t %f\t %f\n", coeff[0], coeff[1], dx[i]);
dy[i] = coeff[0] + coeff[1]*dx[i];
}
Although, all values (coeff[0], coeff[1], dx[i])) are defined inside the loop (checked with print() ) dy[i] is not calculated. I have tried with changing the name dy[i] -> dyy[i] to be sure it does not exist but does not help
have any idea what to do?
oliver |
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Mike Buess
USA
3037 Posts |
Posted - 11/20/2006 : 09:50:42 AM
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Try setting the size of dy before setting its values...
int colNum = wks.AddCol();
Dataset dx(wks,0); // X dataset
Dataset dy(wks,colNum); // Y dataset
dy.SetSize(dx.GetSize());
Mike Buess
Origin WebRing Member |
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Topic |
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plotting polynoms