How to constrain the lower and upper bounds in lsqcurvefit?
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Hi,
For a data set (x, y), I am trying to fit a function f(m, x) using lsqcurvefit. I write as follow:
x=xdata;
y=ydata;
fun=f(m,x);
m0=[m01; m02; m03]; %these are real numbers
lb=[0; 0; 0];
ub=[ub1; ub2; ub3]; %these are real numbers
m=lsqcurvefit(fun, m0, xdata, ydata, lb, ub);
However, sometimes it obeys the bounds and sometimes it does not while fitting. Could anyone please help me if there is any way of constraining the bounds?
Thank you very much in advance!
Kind regards,
Arun
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Matt J
2019년 1월 2일
편집: Matt J
2019년 1월 2일
This seems to work okay,
for i=1:2
[xdata,is]=sort(realpart(:, i));
ydata=imaginarypart(is, i);
fun=@(m,xdata) ((((m(2)-m(1)).*tan(pi.*m(3)/2))/2)+((sqrt((((m(2)-m(1)).*tan(pi.*m(3)/2)).^2)-(4.*((xdata.*xdata)-(xdata.*(m(1)+m(2)))+(((m(1)+m(2)).^2)/4)-(((m(2)-m(1)).^2)/(4.*((sin(pi.*(m(3)-1)/2)).^2)))+(((m(2)-m(1)).^2).*((tan(pi.*m(3)/2)).^2)/4)))))/2));
m0=[0.45; 0.1815; 0.0735];
lb=[0; 0; 0];
ub=[2, 0.75, 0.25];
[m,resnorm,residual,exitflag,stats]=lsqcurvefit(@(m,xd) abs(fun(m,xd)), m0, xdata, ydata, lb, ub);
plot(xdata, ydata, 'o', 'linewidth', 1.5); hold on;
plot(xdata, fun(m, xdata), '-', 'linewidth', 1.5);
output(i, 1:3)=m(1:3, 1);
end
output =
0.3522 0.0000 0.1771
0.3676 0.0239 0.1444
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