For Loop with index inside of a Matrix

Hi all, I am trying to compute this 6x6 matrix associate with index k. My code looks like this:

T=zeros(6,6);
for k=1:1:5;
   S(k)=exp(2.*k.*pi.*1i./(n+1))

     %T(k,:)=zeros(k,:);
     T(k,:)=[-G1  G1+G2+G3+S(k)*C1     -G3-S(k)*C2     0       0       0; 
                0            -G3             0             0       0       0;  
                0             0             -G4       G4+G5+G6+S(k)*C3    -G5       0;
                0             0              0           -G6     -S(k)*C4      0;   
                0             0              0            0       -G7     G7+S(k)*C5;
                1             0              0            0        0       0];

end

The error I got is "Subscripted assignment dimension mismatch." at "T(k,:)=[-G1 G1+G2+G3+S(k)*C1 -G3-S(k)*C2 0 0 0;"

How to fix this? Where does it go wrong? Thank you for your inputs.

Frank

Answer 1

[Sean de Wolski]

It looks like you are tring to stuff a 6x6 matrix into a 1x6 vector, hence the error. Use

dbstop if error

then run your code. It will stop on that line, evaluate the LHS and the RHS and error should become obvious.

[Frank Liu]

It does stop at the line where my matrix begins, so I am thinking my LHS isn't match the 6x6 matrix.

Than how should I write this argument? I am still new to Matlab. Thanks.

[Sean de Wolski]

I don't know what you want, so let's talk it through and that should make it clear:

You want to calculate a 6x6 matrix for each k value - what do you want to do with this matrix? Do you want to add it to the previous? (T = T+[new_stuff])

Do you want to store it as it's own 6x6 ?

T(:,:,k) = new_stuff

Do you want to store it as a 36x1 column vector?

T = zeros(36,6);

for ii...

T(:,ii) = new_36x1

Please elaborate on the goal and it should become clear

[Frank Liu]

Sorry for the confusion. I want six 6x6 matrix "T". Each matrix will have a k value.

I tried "T(:,:,k) = new_stuff". It does work but now T is a 6x6x5 matrix.

If I need to pull out a T when k=1, should I write T(:,:,1)?

[Sean de Wolski]

ayuh!