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Randomizing the rows of a matrix and reversing

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Mohsin Shah
Mohsin Shah on 1 Aug 2017
Commented: Mohsin Shah on 2 Aug 2017
Hello, I have a 988 x 3 matrix (say the vertices of 3D object) and I want to randomize the rows of this matrix and then do the reverse process to get the original matrix. I am using the following code to do the job:
The above code doesn't produce the original matrix. Can someone highlight my mistake and give me a solution?

Accepted Answer

José-Luis
José-Luis on 1 Aug 2017
Edited: José-Luis on 1 Aug 2017
If you want to return to the original matrix, you need to keep it. There is no way to undo a random permutation, unless your data was ordered/structured in some way (was it?). If it was ordered, how so? The key word is random.
Just to be psychotic about it. randperm() is not random but pseudo-random. If you knew the state of the random number generator, it could be possible to go back to the original. I am guessing this is not what you had in mind.
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Mohsin Shah
Mohsin Shah on 2 Aug 2017
Thank you so much. This is only to permute the locations for achieving more security. The hiding itself is a complex algorithm and has nothing to do with permutation.

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