Command to reshape matrix diagonally

Question

fr_sk 2016-4-8

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/277902-command-to-reshape-matrix-diagonally

评论： Andrei Bobrov 2016-4-8

Hi, i'd like to transform

X =  1   100    40
 107    30
  90    50
 120    60

into

Y =  1   100    40     3    90    50
     2   107    30     4   120    60

I thought

Y = reshape(X,2,6)

would do the trick but it didn't give me the matrix I was looking for.

Any quick ideas will be appreciated.

Thanks!

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Answer 1

Andrei Bobrov 2016-4-8

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https://ww2.mathworks.cn/matlabcentral/answers/277902-command-to-reshape-matrix-diagonally#answer_217042

编辑：Andrei Bobrov 2016-4-8

在 MATLAB Online 中打开

% X - array with size [5541888 x 7]
% m2 - number of rows in second array, m2 = 1536
[~,n] = size(X);
out = reshape(permute(reshape(X',n,m2,[]),[1 3 2]),[],m2)';

or

[m,n] = size(X);
a = mat2cell(X,m2*ones(m/m2,1),n);
out = [a{:}];

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fr_sk 2016-4-8

This is the perfect solution, it works like charm!!! Thank you so much!

Just so I understand what you did: What does [1 3 2] do in this case? Also why X' instead of X ?

Andrei Bobrov 2016-4-8

在 MATLAB Online 中打开

rewrite on separate commands:

[~,n] = size(X);
a = reshape(X',n,m2,[]);
b = permute(a,[1 3 2]);
out = reshape(b,[],m2)';

Please read about MATLAB functions: ' - transpose, reshape, permute.

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Answer 2

Rick Rosson 2016-4-8

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/277902-command-to-reshape-matrix-diagonally#answer_217036

在 MATLAB Online 中打开

Y = [ X(1:end/2,:) X(end/2+1:end,:) ];

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fr_sk 2016-4-8

Wow, thanks a lot for the fast response. This works very well for this example. My actual dataset has the dimensions of 5541888 x 7, which I want to stack according to your method to obtain a 1536 X 25256 matrix.

I wanted to apply your idea, but then I realized that I have to enter the code for each column manually. Do you think there is a way to do it for these dimensions?

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