Create Block Toeplitz Matrix

How can I create a block toeplitz matrix with all zero elements apart from the main diagonal band?

If A and B are scalars the example below works

rng(123)
A = rand(3);
B = rand(3);
T=100;

Omega = toeplitz([A,B,zeros(T,3)]);

[Jan]

A and B are not scalars in your example and if they are some, the last line fails also.

Please show us, which output you want to get.

[Marco Lago]

Sorry, my bad. With the scalar example I meant something like the example below. Which gives a squared toeplitz matrix like the folloqing but where A and B are, say, 3x3 matrices.

A B 0 ...0

B A B ...0

0 B A ...0

0 0 B ...0

: : : ....B

0 0 0 ...A

A =1;
B = 2;
T=100;
Omega = toeplitz([A;B;zeros(T,1)])

Answer 1

[Stephen23]

C = {zeros(3),randi(9,3),randi(9,3)}; % {0,B,A}
N = 5;
X = toeplitz([3,2,ones(1,N-2)]);
M = cell2mat(C(X))

M = 15×15

5 5 9 4 9 7 0 0 0 0 0 0 0 0 0 8 2 3 4 9 7 0 0 0 0 0 0 0 0 0 9 2 3 2 1 9 0 0 0 0 0 0 0 0 0 4 9 7 5 5 9 4 9 7 0 0 0 0 0 0 4 9 7 8 2 3 4 9 7 0 0 0 0 0 0 2 1 9 9 2 3 2 1 9 0 0 0 0 0 0 0 0 0 4 9 7 5 5 9 4 9 7 0 0 0 0 0 0 4 9 7 8 2 3 4 9 7 0 0 0 0 0 0 2 1 9 9 2 3 2 1 9 0 0 0 0 0 0 0 0 0 4 9 7 5 5 9 4 9 7

Answer 2

[Stephan]

Try:

rng(123)
A = eye(3);
B = randi(10,3);
Omega = kron(A,B)

gives:

Omega =

     7     6    10     0     0     0     0     0     0
     3     8     7     0     0     0     0     0     0
     3     5     5     0     0     0     0     0     0
     0     0     0     7     6    10     0     0     0
     0     0     0     3     8     7     0     0     0
     0     0     0     3     5     5     0     0     0
     0     0     0     0     0     0     7     6    10
     0     0     0     0     0     0     3     8     7
     0     0     0     0     0     0     3     5     5

[Marco Lago]

but that will be a block diagonal matrix, not toeplitz

[Stephan]

What is your desired output? Do you mean:

rng(123)
A = randi(10,1,4)
T=3;
Omega = toeplitz([A,zeros(1,T)]

Omega =

     7     3     3     6     0     0     0
     3     7     3     3     6     0     0
     3     3     7     3     3     6     0
     6     3     3     7     3     3     6
     0     6     3     3     7     3     3
     0     0     6     3     3     7     3
     0     0     0     6     3     3     7