How to create a 3D matrix from subtracting 2D matrices (like creating 2D matrix from subtracting vectors)?

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Mohit Kumar 2022-1-19

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https://ww2.mathworks.cn/matlabcentral/answers/1631840-how-to-create-a-3d-matrix-from-subtracting-2d-matrices-like-creating-2d-matrix-from-subtracting-vec

评论： Mohit Kumar 2022-1-19

Hi,

I wish to extend the behavior of subtracting a row vector and a column vector to matrices. Let me provide an example: Suppose A and B are two n x n matrices. I want to obtain matrix C such that C(:,:,i) = A(:,i)-B(i,:), i runs from 1 to n.

Is there a way to do this without for-loops?

Thanks,

Mohit.

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Answer 1

Stephen23 2022-1-19

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https://ww2.mathworks.cn/matlabcentral/answers/1631840-how-to-create-a-3d-matrix-from-subtracting-2d-matrices-like-creating-2d-matrix-from-subtracting-vec#answer_877325

在 MATLAB Online 中打开

C = permute(A,[1,3,2]) - permute(B,[3,2,1])

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Stephen23 2022-1-19

在 MATLAB Online 中打开

format compact
A = randi(9,3,3)
A = 3×3
     5     9     5
     1     5     9
     5     9     6
B = randi(9,3,3)
B = 3×3
     6     8     6
     8     7     3
     5     9     5
C = permute(A,[1,3,2]) - permute(B,[3,2,1])
C = 
C(:,:,1) =
    -1    -3    -1
    -5    -7    -5
    -1    -3    -1
C(:,:,2) =
     1     2     6
    -3    -2     2
     1     2     6
C(:,:,3) =
     0    -4     0
     4     0     4
     1    -3     1