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matrix operaions sums multiplications

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Tiina on 27 Dec 2014
Closed: MATLAB Answer Bot on 20 Aug 2021
If I have 2 matrices say
B size (100, 2)
A size (100, n)
How to conduct the following operation?
B(1,1) * A(:,1) + B(1,2) * A(:,2)
Then in another column
B(2,1) * A(:,1) + B(2,2) * A(:,2)
And so on , that is each row of B multiplied by A. with loops or without. Thanks
  1 Comment
Image Analyst
Image Analyst on 27 Dec 2014
When do columns 3 to n of A ever get involved in this calculation???

Answers (2)

Roger Stafford
Roger Stafford on 27 Dec 2014
C = A(:,1:2)*B.';

Shoaibur Rahman
Shoaibur Rahman on 27 Dec 2014
It seems that A(:,3:end) are never used. If that is the case, then you can simply use a for loop:
for k = 1:size(B,1)
out(:,k) = B(k,1)*A(:,1)+B(k,2)*A(:,2);

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