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

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.

Answer 1

[Stephen23]

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

[Stephen23]

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

[Mohit Kumar]

Very elegant! Thanks!