How to extract matrix element from an indexed matrix

Hi,

How can I extract matrix element from an indexed matrixS(:,:,k)? I know S(2,2) would extract 2nd row,2nd column but how to do it with S(:,:,k) which are calculated in loop k=1:n?

Thanks

Answer 1

[Star Strider]

You can extract them as (MxN) matrices, but you have to do operations on them inside the loop (unless you want to do the extremely unwise and strongly discouraged operation of creating individually-named (MxN) matrices).

The squeeze function is your friend here.

For example, this works:

S = randi(25, 7, 6, 5);
v = randi(10, 6, 1);
for k1 = 1:size(S,3)
    R(:,:) = squeeze(S(:,:,k1));
    Q(:,k1) = R*v;
end

The Q matrix here contains the results of the vector multiplications inside the loop.