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mwmarmw
Poland
1 Posts |
 Posted - 07/05/2021 : 07:13:09 AM
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Hello, I am doing NLCF. My question is how do I set up parameter initialization for a function of the following form:
y=k*(x^c)+l*(x^d)+a*(1-exp(-b*x))
I tried something like that:
sort( x_y_curve );
//smooth( x_y_curve, 2 );
Dataset dx;
x_y_curve.AttachX(dx);
dx = ln(dx);
x_y_curve = ln( x_y_curve );
Dataset coeff;
coeff.SetSize(2);
fitpoly( x_y_curve, 1, coeff);
k= exp( coeff[0] );
c = coeff[1];
coeff.SetSize(3);
fitpoly( x_y_curve, 1, coeff);
l = exp( coeff[0] );
d = coeff[1];
int sign;
double a1;
b = -get_exponent_cuv(x_y_curve, &a1, &a, &sign);
a = (a1-sign*exp(a)) / 2;
but there is definitely some error in it (maybe in a different place of the function being built?), Because although the curve fits well, the parameters obtained have undefined values.
I will appreciate any help |
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Chris D
428 Posts |
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Topic |
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Creating a new Parameters Initialization Script
