Picking out a value from a Vector in a Loop iteration

Question

Christopher 2013-4-24

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/73427-picking-out-a-value-from-a-vector-in-a-loop-iteration

What i would like to do is from a vector = [a b c d], obtained from calculating the distance between 2 vectors, i want in my iteration to be able to choose lets say c if c is the least distance away. I am trying to implement LBG design algorithm for data compression. This is what i have so far clear all close all

x1 = [8.4 1.9 0.2 6.8 6.8 3.0 3.8 5.4 8.3 1.5 5.1 7.0 7.1 3.8 4.3 8.6 3.0 8.5 1.9 5.9]'; y1 = [2.5 2.5 2.5 7.5 7.5 2.5 7.5 7.5]'; X = reshape(x1,2,10)'; Y = reshape(y1,2,4)';

figure(1) plot(X(:,1),X(:,2),'*');xlabel('X1');ylabel('X2'); hold on plot(Y(:,1),Y(:,2),'o');

for i = 1:length(X) for m =1:length(Y) d = X(i,:)-Y(m,:); x(i,m) = sqrt(sum(d.^2)) end end

    x will spit out a 10 by 4 matrix.  I want to pick out the least distant value in the for loop to get a 10 by 1 matrix

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Matt Kindig 2013-4-24

If I understand you correctly, you just want the smallest value for each row. After your two for loops, just add

smallestRow = min(x, [], 2);

Matt Kindig 2013-4-24

By the way, the delay in you getting a response was because your code was not formatted correctly. In the future, please use the '{} Code' button above to format your code. After copy-pasting your code into the question window, highlight it and click the Code button. This will make it easier for forum members to understand your problem more easily.

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Answer 1

Ahmed A. Selman 2013-4-24

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/73427-picking-out-a-value-from-a-vector-in-a-loop-iteration#answer_83371

Within your same code:

...
plot(Y(:,1),Y(:,2),'o');
z=zeros(1,length(X)); % Add this
for i = 1:length(X) 
    for m =1:length(Y) 
        d = X(i,:)-Y(m,:); 
        x(i,m) = sqrt(sum(d.^2)); 
    end
    z(i)=min(min(x(i,:))); % Add that
end