MATLAB: Build m x m matrix

urgent question

Hello, I wanna build a matrix of m nods. I have some questions:
1-
   if F=[-3 2 -3]
   for I=1:m;end
   B=eye(I)*F;   ---------(1)
the problem here is F in eq (1) is not allowed in matlab, what I have to do to built that matrix which affected by different values of m?
2-
 A=[5 -3];C=[-3 4];
I wanna use use the three matrices (A,B,C), to get the result to be like
D= [ 5   -3    0    0    0;                  
    -3    2   -3    0    0;         
     0   -3    2   -3    0;    
     0    0   -3    2   -3;  
     0    0    0   -3    4 ]
What do u suggest??
thanks

Best Answer

Basheer - as F is a 1x3 matrix, the only multiplication with eye(I) that will succeed is when I==1 (since that will be a 1x1 matrix multiplied against the 1x3 matrix F).
What are you attempting to achieve by creating this B? Is it the output of D that you want, and so when you supply a different m, you will get different D matrices?
 A = [5 -3];
 B = [-3 2 -3]; 
 C = [-3 4];
 m = 3;
 D = zeros(m+2,size(A,2)+m);
 D(1,1:size(A,2)) = A;
 D(end,m+1:end)   = C;
 for k=1:m
     D(1+k,k:k+size(B,2)-1)=B;
 end
So D becomes
 D =
     5    -3     0     0     0
    -3     2    -3     0     0
     0    -3     2    -3     0
     0     0    -3     2    -3
     0     0     0    -3     4
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