how to find the element which is greater than or equal to its row and smaller or equal to its column in a matrix

Neeta Dsouza answered . 2025-07-07 00:39:22

Copying code from the internet is not always a good way to learn best-practice coding: Solving this problem using loops misses using MATLAB's excellent code vectorization abilities. It would be much neater and faster to use bsxfun instead, like this:

 

function idx = saddle(mat)
row_mx = bsxfun(@ge,mat,max(mat,[],2));
col_mn = bsxfun(@le,mat,min(mat,[],1));
[R,C] = find(row_mx & col_mn);
idx = [R,C];
end

Which gives this:

>> saddle(zeros(5,3))
ans =
   1     1
   2     1
   3     1
   4     1
   5     1
   1     2
   2     2
   3     2
   4     2
   5     2
   1     3
   2     3
   3     3
   4     3
   5     3

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