lsqnonlin question

Question

Shalini 2012-4-18

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/35905-lsqnonlin-question

Consider the following code:

X(1:10304)=xlsread('qs_comp_2.xls',2,'G3822:G14125');
Y(1:10304)=xlsread('qs_comp_2.xls',2,'H3822:H14125');
X(10305:12631)=xlsread('comp.xls',3,'T4259:T6585');
Y(10305:12631)=xlsread('comp.xls',3,'U4259:U6585');
X0=[1012 1400 0.17 -0.0001];
lb = [1012;900;0.17;-0.0001];
ub=[1300;1600;0.3119;10];
StartAt =  [1012;900;0.17;-0.0001];
 options = optimset('MaxFunEvals',10000);
x=lsqnonlin(@(X0)fit_simp(X0,X,Y),StartAt,lb,ub,options);
[total_readings,epsilon_dot_QS,epsilon_dot_MR] = GetMRDetails;
for i=1:total_readings
         Y_new(i)=(X0(1)+X0(2)*(X(i)^X0(3))+X0(4)*log(epsilon_dot_QS/epsilon_dot_MR));
end

Please can anyone help me here:

1) Is the final optimised vector X0 or is it x? That is: which id the final answer X0 or X 2)Is there anything I'm missing in this code?

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Answer 1

Sean de Wolski 2012-4-18

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/35905-lsqnonlin-question#answer_44936

It is x, the output from lsqnonlin. It doesn't look like the above code ever uses the actual optimized value.

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Shalini 2012-4-18

Please can you correct it-I shall be grateful.I'm new to matlab

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Answer 2

Shalini 2012-4-18

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/35905-lsqnonlin-question#answer_44938

在 MATLAB Online 中打开

Why you think so?

My fit_simp function (see properly above) is as below

function diff = fit_simp(x,X,Y)
% This function is called by lsqnonlin.
% x is a vector which contains the coefficients of the
% equation.  X and Y are the option data sets that were
% passed to lsqnonlin.
A=x(1);
B=x(2);
n=x(3);
C=x(4);
[total_readings,epsilon_dot_QS,epsilon_dot_MR] = GetMRDetails;
     for i=1:total_readings
          diff(i)=(A+B*(X(i)^n)+C*log(epsilon_dot_QS/epsilon_dot_MR));
          diff(i)=diff(i)-Y(i);
      end