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Niki
Niki on 6 Jun 2012
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

Accepted Answer

Andrei Bobrov
Andrei Bobrov on 6 Jun 2012
x = [1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
16 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));
  3 Comments
Andrei Bobrov
Andrei Bobrov on 6 Jun 2012
full number of permutation for matricies with size m x n : N = m^n

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