Matlab / Octave中矩阵两列之间的最大欧几里得距离

Question

I need to calculate for a program the maximal euclidian distance of vectors that are put together in a matrix A in Octave.

What I have so far:

for i=1:n 
   for k=i:n+1
      C=A(:,i)-A(:,k);
      maxdiff=max(norm(C),maxdiff);  
   endfor
endfor

This is not working and I don't know why. Any help is appreciated!

Answer 1

You can use pdist from the Statistics Toolbox / Package:

A = rand(3,4); % example data
maxdiff = max(pdist(A.'));

Or, manually:

d = sum(bsxfun(@minus, A, permute(A, [1 3 2])).^2, 1);
maxdiff = sqrt(max(d(:)));