CODEWITHSUNDEEP
matlab
Duck
Duck

Reputation: 39585

Filling a matrix with vectors in loop and apply operation

I am working on matlab with a matrix. I would like to reproduce this matrix and apply sum for elements in rows.

enter image description here

I have two vectors defined by this code:

unitsvector=1:5;
reordervector=1:3;

Then, I create an empty matrix to store the values:

resultvec=zeros(size(unitsvector,2)*size(reordervector,2),3);

Finally, here is the loop I use but it is not working:

for a=1:length(resultvec)
    for b=reordervector
        for c=unitsvector
            resultvec(a,1)=b;
            resultvec(a,2)=c;
            resultvec(a,3)=b+c;
        end
    end
end

How could I reproduce this matrix in matlab. Thanks for your help.

Upvotes: 0

Views: 188

Answers (2)

Adriaan
Adriaan

Reputation: 18177

Why are you looping at all? sum actually has vector support; a simple resultvec = [a(:,1),a(:,2),sum(a,2)] would work.

As to your code: of course it doesn't work. What do you expect to be the contents of a? You create a as a loop index, which runs over the range 1:length(resultvec). Ergo, within each loop iteration a is a scalar. You try to call it like it is a three-element vector. Nor do you define b and c. This might be possible in R, judging where you're coming from, but not in MATLAB.

Upvotes: 1

Matt
Matt

Reputation: 1362

You can use meshgrid for this without a for loop.

[a,b] = meshgrid(1:5,1:3); 
M = [a(:) b(:)];
M(:,3) = sum(M,2); % Create third column by summing first two

Upvotes: 1

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