Zero elements in a matrix more higher than ones (MATLAB)

Dear members,

I want to generate a random binary matrix like this:

M=216;
N=432;
H=randi([0,1],M,N);

But I want to add a condition such that the number of ones '1' must not exceed 3 in each column.

It means for each column we can find (one, two or three ones).

How can I do that please !

Answer 1

[Mike Croucher]

This is almost certainly not the most efficient way of doing it but it seems to work. Will need the statistics and ML toolbox for the randsample function.

numRows = 216;
numCols = 432;
H = zeros(numRows,numCols);
% How many ones are we going to have per column?  Between one and three
numOnesPerCol = randi([1,3],[1,numCols]);
% Randomly choose where on each colum these ones are going to be 
for col=1:numCols
    numOnes = numOnesPerCol(col);  % Number of ones in this column
    indices = randsample(numRows,numOnes)  % Which rows are the ones going to be put
    H(indices,col) = 1;   % Put the ones in this column
end

[high speed]

@Mike Croucher Thank you so much. It works