How to assign a matrix to the diagonals of another matrix in matlab

Question

I have a matrix D = zeros (30, 432); i want to assign d = [ 1 1 0 0; 0 0 1 1; 0 0 0 0]; to the diagonals of matrix D. i have the code below but it doesn't allow me to assign d for every diagonal values in D.

[N,~,P,Q]=size(D);
diagIndex=repmat(logical(eye(N)),[1 1 P Q]);
D(diagIndex)=d;

The output for 30x432 matrix would be like :

What exactly is the output that you want? Please provide that output. Please create a small sample example — Sardar Usama, Jul 15 '18 at 10:24
Well, it has 30 rows and 432 columns. that was just an small example. — lighting, Jul 15 '18 at 10:59
How exactly? if you put d matrix at its place, there cannot be 30 r and 432 cols? — Sardar Usama, Jul 15 '18 at 11:00
I know, it's OK i just want to have d matrix for first 30 columns and other columns would remain zero. — lighting, Jul 15 '18 at 11:37

score 0 · Accepted Answer · answered Jul 15 '18 at 12:03

You can use spdiags to create a diagonal [10 x 108] sparse matrix then use kron to scale and fill the matrix.

d = [ 1 1 0 0; 0 0 1 1; 0 0 0 0]
size_D=[30, 432];
sz = size_D./size(d);
diagonal = spdiags(ones(sz(1),1),0,sz(1),sz(2));
result = kron(diagonal ,d);

How to assign a matrix to the diagonals of another matrix in matlab

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