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# Matrix rows and columns swapping

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Rakesh Belchandan on 11 Nov 2019
Commented: Rakesh Belchandan on 12 Nov 2019
I want to completely change rows and column simultaneously (please see the picture attached)
Is there a function which can do this?
Thanks,
Rakesh

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### Answers (2)

Walter Roberson on 11 Nov 2019
There is no function that can do that simultaneously, at least not the first time.
For any given row and column exchange pattern, it is possible to pre-process the pattern so that doing the same exchange for multiple different arrays would take place simultaneously for that one matrix. Something like
temp = preprocess_exchange(rows_to_exchange, columns_to_exchange);
newA = A(temp);
newB = B(temp);
where preprocess_exchange is a function that would need to be written.

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Walter Roberson on 12 Nov 2019
I should correct myself: you can do this with indexing.
>> A = [1 2 3;4 5 6;7 8 9]
A =
1 2 3
4 5 6
7 8 9
>> A([2 1 3],[2 1 3])
ans =
5 4 6
2 1 3
8 7 9
Rakesh Belchandan on 12 Nov 2019
Thanks. That works for me.

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Akira Agata on 12 Nov 2019
I don't think rows and column can be randomly changed simultaneously.
There should be at least 2 steps, like this:
% Input 3-by-3 matrix
A = reshape(1:9,3,3)';
% Randomize rows and columns
A = A(randperm(3),:);
A = A(:,randperm(3));

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Rakesh Belchandan on 12 Nov 2019
Thanks.

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