我的 kmeans matlab 代码

function [cls,ctr]=kmeans(data,K,tol)
% Kmeans
% input: data K tol
% output: cls: clusters, ctr: centroids
% example:
% data=rand(100,2);
% K=4;tol=0.01;
% [cls,ctr]=kmeans(data,K,tol);
% clr=['r','k','g','b'];
% for k=1:K
%    plot(cls{k}(:,1),cls{k}(:,2),[clr(k),'o']);hold on;
%    plot(ctr(k,1),ctr(k,2),[clr(k),'+']);hold on;
% end

if nargin<=2,tol=0;
end

ctr=data(1:K,:);
N=size(data,1);
while 1
% Assignment step
cls=cell(1,K);                % K clusters
for l=1:N
dl=data(l,:);
d=norm(dl-ctr(1,:));ind=1;
for k=2:K
if norm(dl-ctr(k,:))<d,
ind=k;d=norm(dl-ctr(k,:));
end
end
cls{ind}=[cls{ind};dl];   % data l is in ind-th cluster
end

% Update step
S=0;
for k=1:K                     % calculate new centroids
newctr(k,:)=mean(cls{k});
S=S+norm(newctr(k,:)-ctr(k,:));
end

ctr=newctr;                   % update the centroids
if S<=tol,
break;
end
end