Multiplying elements of a matrix and its transpose row-wise

Question

Gorbz 2021-8-5

0
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https://ww2.mathworks.cn/matlabcentral/answers/892792-multiplying-elements-of-a-matrix-and-its-transpose-row-wise

编辑： Matt J 2021-8-5

I am a novice in Matlab. I have a variable U of the class 'double' and size 500 2 (so it corresponds to a 500x2 matrix). Each row corresponds to a vector so in reality I have 500 vectors. I want to take the dot product of each vector with itself and add the results:

result = U(1)'*U(1) + U(2)'*U(2) + ... + U(500)'*U(500)

I cannot figure out how to do this.

EDIT:

For example, if U = [1 2; 3 4] then I can define result1 = dot(U(1,:)',U(1,:)) and result2 = dot(A(2,:)',A(2,:))

Then I need to do result1 + result2. So I need to store the dot product of each row of U with it self to a list and then add the elements of the list.

Unfortunately I cannot make the following loop work:

for i = 1:length(A)

result1 = dot(A(i,:)',A(i,:))

end

ANSWER:

y = 0;

for n = 1:length(U)

y = y + dot(A(U,:)',A(U,:))

end

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Gorbz 2021-8-5

I thought I used the standard * multiplication symbol that yields the dot product.

Matt J 2021-8-5

编辑：Matt J 2021-8-5

No, the * multiplication symbol in Matlab means matrix multiplication and U' means the conjugate tranpose of U. Is your intended product operation supposed to produce a 2x2 output or something else?

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