Create 9x9 matrix with RANDI between [0,2] with each 0,1, and 2 repeating three times each per column.

I'm trying to create a 9x9 matrix with random number generation from 0 to 2 using RANDI:

X = randi([0,2], 9,9)

However, I want to force each of the 9 columns to show an equal distribution of 0's, 1's, and 2's (3 x of each number per column). I'm having difficulty finding a loop that can do this. Any help would be great (very new to this type of MATLAB work).

Thanks.

Answer 1

[Abdolkarim Mohammadi]

You can first create a vector with the values you need:

Reference = repelem (0:2,3)';

Then you initialize the 9x9 matrix with zeros(), and finally fill in the columns with random permutations of Reference using randperm().

[Ryan Graham]

Thank you very much for your help, I'm working on filling in the zero's matrix columns using randperm now.

[madhan ravi]

+1

[Ryan Graham]

Running into a problem filling in the matrix at the column addition. I have:

Reference = repelem(0:2,3)';

M = zeros(9,9)

Y = M(randperm(Reference)),:)

[Abdolkarim Mohammadi]

Reference = repelem (0:2,3)';
M = zeros (9);
for i1 = 1:9
    M (:,i1) = Reference (randperm(9));
end

[Ryan Graham]

Excellent, thank you very much for your help, this works and is a nice guide for me going forward. For future reference, if the Matrix is no longer a square, I should be able to just change the M= zeros (9) to a different number of rows and columns?

[Abdolkarim Mohammadi]

Yes. But the number of rows should not change. For example: zeros (9,4). Otherwise, you should update Reference have the same number of elements as the number of rows in M.

Answer 2

[Bruno Luong]

[~,A] = sort(rand(9)); A = mod(A,3)