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How to generate random matrix from another one?

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IM
IM on 19 Sep 2019
Commented: IM on 20 Sep 2019
Hi!
I have a 18 x 57x11 matrix .
How can I make a new random matrix (the same size) , which is generated by "shuffling" the values of the original matrix?
A lot thanks in advance!

  1 Comment

Adam Danz
Adam Danz on 19 Sep 2019
Ha! You got 3 different approaches that use randperm() and reshape().
By the way, your data is not a matrix. A matrix is 2 dimensional, with rows and columns. Your data contains a 3rd dimension which makes it an array. All 3 answers will work no matter how many dimensions are in the input.

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Accepted Answer

Adam Danz
Adam Danz on 19 Sep 2019
Edited: Adam Danz on 19 Sep 2019
You can use randperm() to shuffle the values of array 'm'.
% Original array
m =rand(180, 57, 11);
% Random permutation index
randpermIdx = randperm(numel(m));
% m shuffled
mShuffle = reshape(m(randpermIdx), size(m));
To convince yourself that mShuffle is merely a random reorganization of m with no additional or missing values or duplicate samples, use this line below which should return True.
isequaln(sort(m(:)),sort(mShuffle(:)))

More Answers (2)

Bruno Luong
Bruno Luong on 19 Sep 2019
A is your input matrix
Ashuffle = reshape(A(randperm(numel(A))),size(A))

Adam
Adam on 19 Sep 2019
newMatrix = reshape( oldMatrix( randperm( numel( oldMatrix ) ) ), size( oldMatrix ) );
should work, though I'm sure there are neater ways.

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