different output in kmeans

Question

Elysi Cochin 2013-5-6

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/74779-different-output-in-kmeans

i used kmeans for clustering similar images.... if i run the code first i get the correct clusters..... but without closing matlab if i execute the second time for the same image, it is clustering different output.... why like that..... what shud i do to get the same output whenever i execute the code... please do reply.....

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Youssef Khmou 2013-5-6

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/74779-different-output-in-kmeans#answer_84532

hi, i think this question has been asked before, the reason is that the K-means algorithm starts with random partition so every time you run the code, you get the same result but with different RMSE.

(try to clear the Workspace and re-run ...)

5 个评论
显示 3更早的评论隐藏 3更早的评论

Walter Roberson 2013-5-6

http://www.mathworks.co.uk/matlabcentral/answers/74592-k-means-clustering-result-always-changes#answer_84423

Walter Roberson 2013-5-7

在 MATLAB Online 中打开

Could you indicate

size(repmat(minc, nsamp, 1))
size( bsxfun(@times, (0:nsamp-1).', (maxc - minc) ./
  (nsamp-1)) )

请先登录，再进行评论。

Answer 2

José-Luis 2013-5-6

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/74779-different-output-in-kmeans#answer_84538

编辑：José-Luis 2013-5-6

在 MATLAB Online 中打开

An option is to reset the random number generator to its initial state every time before running your code:

rng default % ->This is the important bit
X = [randn(100,2)+ones(100,2);...
     randn(100,2)-ones(100,2)];
opts = statset('Display','final');
[idx,ctrs] = kmeans(X,2,...
                    'Distance','city',...
                    'Replicates',5,...
                    'Options',opts);

This will always produce the same result, but it sorts of beat the purpose of the function and might produce bad results.

2 个评论
显示无隐藏无

José-Luis 2013-5-6

编辑：José-Luis 2013-5-6

在 MATLAB Online 中打开

For example:

X = [randn(100,2)+ones(100,2);...
     randn(100,2)-ones(100,2)];
opts = statset('Display','final');
[idx,ctrs] = kmeans(X,2,...
                    'Distance','city',...
                    'Replicates',1,...
                    'Options',opts,...
                    'start',[0.25 0.25; 0.75 0.75]);