How do I define an output vector as real and positive
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Hi all
I am currently running this script to fit a complex function on my data using lsqcurvefit.
clear all;
hold off E1=importdata('E1.mat'); %E1 and DR1 are the names of my arrays
DR=importdata('DR1.mat');
hold on plot(E1,DR)
%x(1)=C
%x(2)=f
%x(3)=Eg
%x(4)=G
x0= [1 0 1 0.02 ];
F=@(x,E1)x(1)*exp(1i*x(2))./((E1-x(3)-1i*x(4))^2);
[x,resnorm,~,exitflag,output] = lsqcurvefit(F,x0,E1,DR);
plot(E1,F(x,E1),'--r')
hold off
It is working perfectly except for the part where all the fitted parameters are returned as complex numbers when they should be real and positive. Is there some way to fix this?
Thanks in advance
댓글 수: 1
Star Strider
2014년 9월 21일
I don’t know what you are doing, but (from the Euler identities), exp(1i*x(2)) will be evaluated essentially as cos(x(2)) + i*sin(x(2)), and you are also multiplying x(4)^2 by 1i. If you do not want complex parameters, you will likely have to re-write your model. I would go to the literature to see what others have done in similar situations.
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