Creating a matrix whose entries are matrix

Given a matrix

A = [-4 1 0; 1 -4 1; 0 1 -4];

I want to create a matrix B such that

B = [A I 0; I B I; 0 I B];

where I is identity matrix whose size is equal to size of A. How can I do this?

Answer 1

[Stephen23]

>> A = [-4 1 0; 1 -4 1; 0 1 -4];
>> I = eye(size(A));
>> Z = zeros(size(A));
>> B = [A I Z; I A I; Z I A]
B =
    -4     1     0     1     0     0     0     0     0
     1    -4     1     0     1     0     0     0     0
     0     1    -4     0     0     1     0     0     0
     1     0     0    -4     1     0     1     0     0
     0     1     0     1    -4     1     0     1     0
     0     0     1     0     1    -4     0     0     1
     0     0     0     1     0     0    -4     1     0
     0     0     0     0     1     0     1    -4     1
     0     0     0     0     0     1     0     1    -4

Although perhaps what you want is toeplitz ?:

[Ali Baig]

Thank you Stephen. I will look into the details of toeplitz.

Answer 2

[Ameer Hamza]

I am assuming the in your question, you wrote B by mistake on the Left side of the 2nds statement and they are actually matrix A. If you want to create a big matrix B then follow @Stephen's answer. But If you want them to remain as separate matrices, then you will need a cell array

B = {A I Z; I A I; Z I A};
B =
3×3 cell array
  {3×3 double}    {3×3 double}    {3×3 double}
  {3×3 double}    {3×3 double}    {3×3 double}
  {3×3 double}    {3×3 double}    {3×3 double}

Access each matrix using curly bracket notation. B{1, 2} will access matrix in the first row and second column.

[Ali Baig]

Thank you Hamza.