Combining sub-matrices diagonally within a for loop

clear all;
clc;
close all;
n=[3 1 2];
for kk=1:length(n)
    matrix=zeros(n(kk),n(kk));
    for ii=1:n(kk)
        for jj=1:n(kk)
            val=2*ii+jj;
            matrix(ii,jj)=val;
        end
    end
end
% Dear users, if you put a debug at the very last "end" (row 13), you can
% see that I aim to generate 3 sub-matrices having the size of 3x3, 1x1 and
% 2x2 (see n=[3 1 2]). I want to combine each sub-matrix one each other diagonally.
% I want to get the matrix as a result below:

matrix=[3 4 5 0 0 0;5 6 7 0 0 0;7 8 9 0 0 0;0 0 0 3 0 0;0 0 0 0 3 4;0 0 0 0 5 6];

%Is there any simple way to do it?
%Thanks in advance!

Answer 1

[Bruno Luong]

submats = arrayfun(@(n) 2*(1:n)'+(1:n),[3 1 2],'unif',0)
matrix = blkdiag(submats{:})

[Rengin]

% Thanks for the answer but I need more explanation because
% I have a much bigger matrix than n= [3 2 1]
% Is it fine to change the matrix as:
submats = arrayfun(@(n) 2*(1:n)'+(1:n),n,'unif',0);
matrix = blkdiag(submats{:});
% What is the function of @(n)? Which part of the code gives me
% length(n)=3? It is important for the original code I am working on. 

[Bruno Luong]

"What is the function of @(n)?"

Please see anonymous function

[Rengin]

I would really appreciate if you can look at my similar question on https://www.mathworks.com/matlabcentral/answers/475992-combination-of-sub-matrices-generated-within-a-for-loop? Your suggestion is cool, I really like to apply it!

[Bruno Luong]

I actually wait to see what do you learn and how you manage to adatp the above code to this tiny change.

Answer 2

[Rengin]

I actually tried the combination of submats = arrayfun(@(n) rad(1:n)*h(1:n),n,'unif',0) but it didn't work.

[Bruno Luong]

n=[3 1 2];
rad=[0.04 0.02 0.01];
h=[10 12 15];

submats = arrayfun(@(n,r,h) r*h*ones(n),n,rad,h,'unif',0);
...

[Rengin]

Now I understand better! Thanks a lot