MATLAB: How randomly choose pairs of elements from a squared matrix and put them in an other matrix

matrix random choose pairs elements function

Hi, I have a matrix A
A =
     1     4     2     3
     4     3     1     2
     3     2     4     1
     2     1     3     4
How to make different groups of two elements from this matrix? But the chosen elements (from the matrix A) have to be adjacent in the matrix A. for example A(1,1) & A(1,2) are adjacent and so they can be chosen. and A(1,1) & A(4,3) can't be chosen to make a group. I'd like to create a function which randomly choose these elements from A. And the function generates an other matrix containing the (2 by 2) different groupements randomly created.
example "function group":
V=group(A)
V=  1 4
  3 2
  4 2
  3 1
  2 1
  4 3
  3 2
  1 4
This new V matrix is made of groups
A(1,1)&A(2,1)
A(2,2)&A(4,1)
A(1,2)&A(1,3)
...
Hope you understand what I mean. In fact we randomly choose pairs of elements in the matrix A. thank you!

Best Answer

m=5
n=numel(A)
ii=0
while ii<m
  id=randperm(16);
  [ii1,jj1]=ind2sub(size(A),id(1));
  [ii2,jj2]=ind2sub(size(A),id(2));
  if and(abs(ii1-ii2)<=1,abs(jj1-jj2)<=1);
      ii=ii+1;
      B(ii,:)=[A(id(1)) A(id(2))]
  end
end
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