function [x,esq,j] = kmeans(d,k,x0)
%KMEANS K-means 舅絆府硫闌 撈儈茄 氦磐 劇磊拳 [X,ESQ,J]=(D,K,X0)%澇仿 牢磊:
% D 單撈磐 氦磐(one per row)
% K 吝繳 骯薦
% X0 檬扁 吝繳藹(可記)
%
%免仿 牢磊:
% X 免仿 凱 氦磐(K 俺狼 凱)
% ESQ 乞閉 磊鉸 坷瞞(mean square error)
% J 阿 單撈磐 氦磐啊 絹蠢 吝繳俊 加竅綽啊狼 禍牢 
%
%   VOICEBOX 傍俺家膠 薦瀝
%   VOICEBOX home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html
%
[n,p] = size(d);
if nargin<3
   x = d(ceil(rand(1,k)*n),:);
else
   x=x0;
end
y = x+1;
iter = 0;
while any(x(:) ~= y(:))
   iter = iter + 1;
   z = disteusq(d,x,'x');
   [m,j] = min(z,[],2);
   y = x;
   for i=1:k
      s = j==i;
      if any(s)
         x(i,:) = mean(d(s,:),1);
      else
         q=find(m~=0);
         if isempty(q) break; end
         r=q(ceil(rand*length(q)));
         x(i,:) = d(r,:);
         m(r)=0;
         y=x+1;
      end
   end
end
esq=mean(m,1);