Getting a j x k Matrix from j and k-dimensional Vectors Without a For Loop?

Suppose I have two column vectors:

J = j x 1 vector

K = k x 1 vector

And I want to create a j x k matrix, W:

W = j x k matrix

where the columns of W are formed by multiplying the corresponding element of K by the vector J.

The for loop to create W looks like this :

% J = j x 1 vector
% K = k x 1 vector
W = zeros(length(J),length(K));
for i = 1:1:length(K)
    W(:,i) = K(i)*J;
end

Numerical example:

J = [1 2 3]';
K = [4 5]';

should result in

W =
     4     5
     8    10
    12    15

Is there any way I can avoid the for loop here? Thanks!

[per isakson]

Homework?

[Mark Rzewnicki]

Nope, just a project for fun on the side. I'm looking at large computing times here so I'm anxious to avoid as many loops as possible.

Answer 1

[per isakson]

See Matrix multiplication

>> J*K'
ans =
     4     5
     8    10
    12    15

[Mark Rzewnicki]

Hah, now I see why you asked if it was homework. Should have been obvious that all I needed to do was transpose.

Thank you!