It seems like the answer to this should be simple, but I am stumped. I have a matrix of Nx3 matrix where there 1st 2nd and 3rd columns are the X Y and Z coordinates of the nth item. I want to calculate the distance from the origin to the item. In a non vectorized form this is easy.
distance = norm([x y z]);
or
distance = sqrt(x^2+y^2+z^2);
However, in vectorized form its not so simple. When you pass a matrix to norm it no longer returns the Euclidean length.
distance = norm(matrix); %doesn't work
and
distance = sqrt(x(:,1).*x(:,1)+y(:,2).*y(:,2)+z(:,3).*z(:,3)); %just seems messy
Is there a better way to do this?
Try this:
>> xyz = [1 2 3; 4 5 6; 7 8 9; 2 8 4]
xyz =
1 2 3
4 5 6
7 8 9
2 8 4
>> distance = sqrt(sum(xyz.^2, 2))
distance =
3.74165738677394
8.77496438739212
13.9283882771841
9.16515138991168