L2_distance_1.m

% compute squared Euclidean distance
% ||A-B||^2 = ||A||^2 + ||B||^2 - 2*A'*B
function d = L2_distance_1(a,b)
if (size(a,1) == 1)
  a = [a; zeros(1,size(a,2))]; 
  b = [b; zeros(1,size(b,2))]; 
end
aa=sum(a.*a); bb=sum(b.*b); ab=a'*b; 
d = repmat(aa',[1 size(bb,2)]) + repmat(bb,[size(aa,2) 1]) - 2*ab;
d = real(d);
d = max(d,0);