reshuffle a symmetric matrix

1 次查看（过去 30 天）

Muhammad Shafique 2011-6-13

1
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/9365-reshuffle-a-symmetric-matrix

Hi all, I have a large symmetric matrix (600*600)and need to reshuffle the elements randomly while keeping the matrix symmetric.

Could anyone help? I shall be grateful.

Regards, Shafique

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Andrei Bobrov 2011-6-13

3
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/9365-reshuffle-a-symmetric-matrix#answer_12889

在 MATLAB Online 中打开

sz = size(A);
B = zeros(sz);
vtl = nonzeros(tril(reshape(1:numel(A),sz)));
B(tril(true(sz))) = A(vtl( randperm(length(vtl))));
B = B + tril(B,-1).';

2. More variant - don't modify main diagonal

sz = size(A);
B = diag(diag(A));
vtl = nonzeros(tril(reshape(1:numel(A),sz),-1));
B(tril(true(sz),-1)) = A(vtl( randperm(length(vtl))));
B = B + tril(B,-1).';

3. OR main diagonal - zeros (modify last row of the previous cod)

B = B + tril(B,-1).'

4 个评论
显示 2更早的评论隐藏 2更早的评论

Muhammad Shafique 2011-6-13

Hi Andrei. I needed to reshuffle the elements only within a triangle but excluding the diagonal. The variant you added does exactly that. Thanks a lot.