How to get back the original matrix?

Question

Ammy 2022-3-25

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1680319-how-to-get-back-the-original-matrix

回答： Torsten 2022-3-25

采纳的回答： Torsten

A=[1 2 3 2;4 1 2 3;3 4 3 2;2 4 1 1];

>> R=[1 3 4 2];

>> B=A(R,:);

>> C=B(:)';

>> D=[1 0 0 1 0 1 0 1 0 1 0 0 1 1 0 1];

>> E=C(D==1);

Can we get back A?

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KSSV 2022-3-25

Already you have A...

Ammy 2022-3-25

Yes But by the reverse process?

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Answer 1

Torsten 2022-3-25

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https://ww2.mathworks.cn/matlabcentral/answers/1680319-how-to-get-back-the-original-matrix#answer_926804

在 MATLAB Online 中打开

A = [1 2 3 2;...
    4 1 2 3;...
    3 4 3 2;...
    2 4 1 1]
R = [1 3 4 2];
B = A(R,:);
Rinv(R) = 1:numel(R);
A_recovered = B(Rinv,:)

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Answer 2

Chunru 2022-3-25

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1680319-how-to-get-back-the-original-matrix#answer_926659

在 MATLAB Online 中打开

A=[1 2 3 2;4 1 2 3;3 4 3 2;2 4 1 1];
% Reordering the rows of A is reversible
R=[1 3 4 2];
B=A(R,:);
% Straightening up the matrix into vector is also reversible
C=B(:)';
% Picking up part of the data is not reversible
D=[1 0 0 1 0 1 0 1 0 1 0 0 1 1 0 1];
E=C(D==1);