Matrix Multiplication with its transpose in the loop

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Mystery Devil
Mystery Devil 2017-1-21
回答： Walter Roberson 2017-1-22
Hi,
Let's say I have a matrix
A = [1 2 3 4 5
2 3 4 5 6
3 4 5 6 7
4 5 6 7 8]
I need to do matrix multiplication i.e. A'*A, but not all the rows and the column at once. For example, I want to multiply the first two column of the matrix first and obtain a result (let's say r1), then column 1, 2 and 3 multiplied with its transpose, obtain the result (let's say r2) and then column 1,2,3, and 4 multiplied with its transpose and the result is r3 and so on. I have to save the result in the matrix, let's say B
B = [r1 0 0 0
r1 r2 0 0
r1 r2 r3 0
.....]
Can anyone help me with this?
Thank you!
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Mystery Devil
Mystery Devil 2017-1-22
Hey John, I know I should use the loop, but that's what I am trying to figure out. I don't know how to loop it

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Walter Roberson
Walter Roberson 2017-1-22
for k=1:size(A,2)
T=A(:, 1:k);
B{k} = T'*T;
end

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