How to create an Nn x Nn matrix from N number of matrices of n x n size each?

Here Xv is a 3x3 size matrix, A is a 3x3 matrix and samples = 1000 . I wish to create a 3000X3000 size matrix sigma by taking product of Xv and A and then putting the so obtained 3x3 matrix into the huge matrix of this form. I was trying this but it didnt work.

for i=1:1:samples/3

for j=1:1:samples/3

if i==j

sigma(i,j)=Xv(:,i);

elseif i<j

sigma(i,j)=Xv(:,i)*(A^(j-i))';

else

sigma(i,j)=A^(i-j)*Xv(:,i);

end

end

end

Answer 1

[KSSV]

m = fix(samples/3) ; 
signma = cell(m) ; 
for i=1:m
    for j=1:m
        if i==j
            sigma{i,j}=Xv(:,i);
         else 
            sigma{i,j}=A*Xv(:,i);
        end
    end
 end

[Richa Dubey]

Adding cell2mat(sigma) at the end completed the code. It worked! Thanks a lot!