MATLAB: Create a matrix using offset elements of a vector

MATLABmatrixmatrix arrayvector

Let say I have a vector v = [v1, v2, v3], I would like to create a non-square matrix putting the vector v as tridiagonal elements like this ,
matrix = [v1, v2, v3, 0, 0, 0,…, 0;
0 , v1,v2,v3, 0, 0 ,…,0;
0 , 0, v1,v2,v3,0,…..,0;]
I know there's a diag command but it's only for square matrix. What's the way of creating a non-square matrix?

Best Answer

Try blktridiag:
A = blktridiag([1;2],[3;4],[5;6],4); 
full(A) 
ans = 
     1     5     0     0 
     2     6     0     0 
     3     1     5     0 
     4     2     6     0 
     0     3     1     5 
     0     4     2     6 
     0     0     3     1 
     0     0     4     2
https://www.mathworks.com/matlabcentral/fileexchange/10603-block-tri-diagonal-matrices
Run help blktridiag for more info
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