Multiplying vectors through a for loop in Matlab

Question

I have 3 vectors and I want to multiply each of them with it's transpose for example I have A1=[-1 1 -1 1] and I want to find At1=A1'*A1. However, I have several vectors and will be adding more than 3 vectors. So, I constructed a for loop to do this for me however, it is not working and I don't know why. Below is my code:

A(1)=[-1 1 -1 1];
A(2)=[1 1 1 -1];
A(3)=[-1 -1 -1 1];

for i=1:3
    At(i)=A(i)'*A(i)
    i=i+1 
end

At=At1+At2+At3

Can someone help?

MinaKamel MinaKamel · Accepted Answer · 2015-03-22T00:35:28

You can achieve what you want like this:

A(1,:)=[-1 1 -1 1];
A(2,:)=[1 1 1 -1];
A(3,:)=[-1 -1 -1 1];

At = trace(A * A'); %sum of the A(i,:)*A(i,:)'

PS. don't do i=i+1 in your loop, it is done automatically for you.

Multiplying vectors through a for loop in Matlab

1 Answers