Problem With Combined for Loop.

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Ot 2014-2-27

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评论： Mischa Kim 2014-2-27

I have a problem with a combined for-loop. For every value of i, I want to compute j(=101) values of B to analyse further. Right now I tried the loop standing below, but I get the error: ??? Subscripted assignment dimension mismatch in the first line below the for assignments. I already tried to compute it without a loop, and then it works, but not in the loop.

for i= 1:length(A)

    for j = 1:(2*50+1)
Ang(i,j) = B([A(1,i)-50]:[A(1,i)+50]);
AngAbs(i,j) = abs(Ang(i,j));
ix1(i) = find(AngAbs(i,j)>0.4,1,'first')+(A(1,i)-50);
ix2(i) = find(AngAbs(i,j)>0.4,1,'last')+(A(1,i)-50);
Dir(i) = sum(B([ix1(i)]:[ix2(i)]));
    end
end

I hope you can help me.

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Mischa Kim 2014-2-27

编辑：Mischa Kim 2014-2-27

What are A and B, size, content?

Ot 2014-2-27

A = Midpoint of Angle index and Value [2x8] matrix. For this loop I only need the Index = first row.

B = Angle between different samples. This is an [1x619] matrix.

So what I basically want to do is to compute for each Midpoint of the Angle a beginning and end of the angle ( which I do with the threshold.) Then I take the Beginning and End of the Angle, and compete the difference in Angle by summating the differences for each sample.

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Answer 1

Mischa Kim 2014-2-27

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https://ww2.mathworks.cn/matlabcentral/answers/119346-problem-with-combined-for-loop#answer_126351

在 MATLAB Online 中打开

Ot, in the command

Ang(i,j) = B([A(1,i)-50]:[A(1,i)+50]);

you are assigning a vector of length 101 to Ang(i,j), which is a scalar .

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Ot 2014-2-27

Ok. Thanks for explaining this. How should I fix this?

Mischa Kim 2014-2-27

在 MATLAB Online 中打开

Assuming I correctly understand your problem you could do

 for i = 1:length(A)
    for j = 1:(2*50+1)
       AngAbs = abs(B([A(1,i)-50]:[A(1,i)+50]));
       ix1(i) = find(AngAbs>0.4,1,'first')+(A(1,i)-50);
       ix2(i) = find(AngAbs>0.4,1,'last')+(A(1,i)-50);
       Dir(i) = sum(B([ix1(i)]:[ix2(i)]));
    end
 end