distmat(V);

function L = distmat(V);

%
% Returns the Distance Matrix (n x n) given coordinates V (n x 2).
% 
% L = distmat(V);
%
%
% Author : Sbastien PARIS
%


[n , d] = size(V);


if( (d ~=2) || (n < 2) )
    
    error('Cities coordinates must be (n x 2)');
    
end


n2      = n*n;

On      = ones(n , 1);


ind_x   = (1 : n);

ind_y   = ind_x';




L       = reshape(sqrt(sum((V(reshape(ind_x(On , :) , n2 , 1) , :) - V(reshape(ind_y(: , On) , n2 , 1) , :)).^2 , 2)) , n , n);   % Distance Matrix (n x n)