How to create a random binary matrix with equal number of ones in each column and equal number of 1 in each row ?

Hi All,

I want to create a random binary matrix with equal number of ones in each column and also equal number of ones in each row.

Appreciate if anyone have an idea to implement this in Matlab.

Thanks.

[madhan ravi]

Give an example of your desired output

[Stephen23]

https://www.mathworks.com/matlabcentral/answers/337211-how-to-create-random-binary-matrix-with-specified-number-of-ones-in-each-row-and-column

[Raghwan Chitranshu]

@Madhan thanks for the comment .

Basically I am looking to construct a matrix with these conditions

1. no all 0 coulmns
2. every column contains an odd number of 1's
3. the number od 1's in each row of the matrix should be made equal or as close as possible to the average (total number of 1's in matrix divided by number of rows)

if you can help regarding this

Regards

Answer 1

[Walter Roberson]

N = 10;   %number of 1s to place
M = 20;   %dimension of matrix

maxtries = 10;   %random placement can fail. How often to retry ?

for trynum = 1 : maxtries
    L = zeros(M,M);
    failed = false;
    for K = 1 : M*N
        cmask = sum(L) < N;
        rmask = sum(L,2) < N;
        locs = find(cmask & rmask & L ~= 1);   %implicit expansion used!
        if isempty(locs)
            fprintf('try %d boxed in at iteration %d\n', trynum, K);
            failed = true;
            break;
        end
        thisloc = locs( randi(length(locs)) );
        L(thisloc) = 1;
    end
    if ~failed
        fprintf('try %d worked\n', trynum);
        display(L)
        break;
    end
end
if failed
    fprintf('Did not succeed in %d tries. You could increase maxtries, but are you sure there is a way to succeed?\n', maxtries);
end

My tests show that with this particular combination, 10 of 20, that success rate in placing within 10 tries is roughly 50% -- suggesting that maxtries should perhaps be increased.

Answer 2

[Bruno Luong]

See the same question here