random

Question

Niki 2012-6-6

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/40416-random

I have a Matrix as follows

 x   = [1     2     3     4     5
         6     7     8     9    10
        11    12    13    14    15
        16    17    18    19    20];

I want to generate a matrix from it that will be for example 100 combination of each element but for example for the first iteration, from first colum only one of them select then from the second as well then from the third as well and untill the end

so I may have like this

x   = [ 6 2 18 4 20 
16 17 3 4 10 
and so on

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Answer 1

Andrei Bobrov 2012-6-6

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https://ww2.mathworks.cn/matlabcentral/answers/40416-random#answer_50080

在 MATLAB Online 中打开

x   = [1     2     3     4     5
   7     8     9    10
  12    13    14    15
  17    18    19    20];

EDIT after Mohammad's coment

[m,n] = size(x);
df = bsxfun(@plus,fullfact(m*ones(1,n)),(0:n-1)*m);
k = randperm(size(df,1));
out = x(df(k(1:min(100,numel(k))),:));

OR

[m,n] = size(x);
xc = mat2cell(x,m,ones(n,1));
cc = cell(1,n);
[cc{:}] = ndgrid(xc{:});
k = randperm(numel(cc{1}));
out =  cell2mat(cellfun(@(x)x(k(1:min(100,numel(k)))'),cc,'un',0));