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

Question

I'm trying to create a 9×9 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

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().