How to index with a changing index

Hi, I would like to construct a matrix L of size nxn that looks like below:

L = [a,b,c,0,0,0,0,...
     0,a,b,c,0,0,0,...
     0,0,a,b,c,0,0,...
     0,0,0,a,b,c,0,...
     ...
     0,0,0,0,...a,b,c];

I'm trying to do this without the for loop.

 i = 2:n-1;
 L(:,i-1:i+1) = repmat([a,b,c],n,1);

However, this doesn't give what I want, and I was warned by the complier that i is a non-scalar operator.

Is there a way to fix this?

Thank you very much!

Answer 1

[DGM]

You can try something like this:

a = 1;
b = 2;
c = 3;

A = toeplitz([a 0 0 0 0 0 0],[a b c 0 0 0 0]);
A = A(1:end-2,:)

A = 5×7

1 2 3 0 0 0 0 0 1 2 3 0 0 0 0 0 1 2 3 0 0 0 0 0 1 2 3 0 0 0 0 0 1 2 3