least-square problem and calling of that function

Question

Erik 2014-4-10

0
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https://ww2.mathworks.cn/matlabcentral/answers/125286-least-square-problem-and-calling-of-that-function

回答： Star Strider 2014-4-10

Hello!

I seem to have a problem with least-square method. I would estimate that the error is simple but I must admit I am code blind at this moment. The file is displayed below and the error directly after. I have marked the rows in the .m-file which is displayed in the error message with >>>.

function[A Deltapar] = MKA(x,y,deltay,n) A = []; Deltapar = []; X=[];

%-----------------------------------------------------------------------------------------------% checking if the input for the matrix size is correct >>>if(size(x)(2)~=1) x=x'; end if(size(y)(2)~=1) y=y'; end if(size(deltay)(2)~=1) deltay=deltay'; end %----------------------------------------------------------------------------------------------- % checking if the matrix x,y, and deltay has the correct size and after that, execute least square method.

if(size(x)(2)==1 && size(y)(2) ==1 && size(deltay)(2)==1)

%----------------------------------------------------------------------------------------------- % Conducting weighted least squares fit on the matrices x and y have the same format. % If not, a message is returned back an x and y are not of the same length. if(length(x)==length(y)) for i=0:n X=[X x.^i]; end sigma=deltay; vminus1 = diag(1./sigma.^2); A = inv(X' * vminus1 * X) * (X' * vminus1 * y); DeltaA = inv(X' * vminus1 * X); Deltapar = sqrt(diag(DeltaA)); else disp('x,y does not have the same length'); end %----------------------------------------------------------------------------------------------- % prints out "you have not written the input on correct form"

else disp('you have not written the input on correct form'); end

??? Error: File: MKA.m Line: 17 Column: 4 ()-indexing must appear last in an index expression.

except this problem I seem to have difficulties with calling this file from another .m-file having code shown in the error message.

the error message is as follow: Error in ==> absnoll2 at 80 [a]= MKA(x,y,deltay,1);

Thanks in advance! sorry for the typo..

Friendly Regards, Erik.