Symmetric binary matrix with diagonal 0 values

Question

Dina Tarek 2019-10-21

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486615-symmetric-binary-matrix-with-diagonal-0-values

评论： Guillaume 2019-11-25

I want to create a symmetric (10x10) binary matrix with n number of ones and the diagonal values have to be 0s. Can anyone help me?

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

James Tursa 2019-10-21

1's can be located anywhere, just not on the diagonal? Random locations? I am assuming n must be even?

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Guillaume 2019-10-21

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486615-symmetric-binary-matrix-with-diagonal-0-values#answer_397508

在 MATLAB Online 中打开

Guaranteed to work on the first try:

Msize = 10;  %size of square matrix
N = 20; %number of ones on each side of the diagonale
M = zeros(Msize);
indices = nonzeros(tril(reshape(1:Msize^2, Msize, Msize), -1));  %get indices BELOW diagonale
M(indices(randperm(numel(indices), N))) = 1;  %pick N indices and fill with 1
M = M | M.'   %do the symmetry

3 个评论
显示 1更早的评论隐藏 1更早的评论

Dina Tarek 2019-11-25

Error using randperm

Inputs must be nonnegative scalar integers.

The above message appeared when I tried diffrent Msize

for example Msize = 12 or 13 or 9 ;

do you know how to solve this error

Guillaume 2019-11-25

Your N is either non-integer, non-positive, or non-scalar.

请先登录，再进行评论。

Answer 2

KALYAN ACHARJYA 2019-10-21

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486615-symmetric-binary-matrix-with-diagonal-0-values#answer_397502

编辑：KALYAN ACHARJYA 2019-10-21

在 MATLAB Online 中打开

Beware: Before Try (I posted it as answer, so that you may get some idea)

n=input('Eneter the value of n: ')
result=zeros(10,10);
while sum(result)~=n
result=ones(10,10)-diag(diag(ones(10,10))) & randi([0 1],[10 10]);
end
result

When it will works, depending on luck, as I have no idea how to control number on 1 generation in random matrics, but I have forced all diagonal elements to zeros.

During running the Matlab (Execution), you can stop it by pression Ctrl+S