Generate random permutation matrix

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Viviana Arrigoni
Viviana Arrigoni on 1 Jul 2017
Answered: James Tursa on 1 Jul 2017
I am trying to generate a random square matrix A of dimension n that has one and only one 1 per row and column. My idea is the following, but as a result I get a matrix of all 1s. What am I doing wrong?
A = zeros(n);
p = randperm(n);
x = 1:n;
p = p';
x = x';
A(p,x) = 1;

Answers (2)

James Tursa
James Tursa on 1 Jul 2017
Another way:
A = eye(n);
A = A(randperm(n),:);

Star Strider
Star Strider on 1 Jul 2017
See if this does what you want:
n = 5; % Set Matrix Size
p = randi([2 n], n); % Create Matrix EXCLUDING ‘1’
x1 = sub2ind(size(p), randperm(n), randperm(n)); % Create Linear Indices For ‘1’
p(x1) = 1; % Put ‘1’ Randomly In Each Row, Column
Experiment to get the result you want.

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