On 04/02/2013 10:26 PM, Pieraut, Francis wrote:

Hi Andy & Ken,

Thanks Ken for the alternative but I am using a cosine distance.

Andy, concerning the computation of the mean, the function has to be configurable too but the default function mean is also good for cosine & bregman divergence (http://www-users.cs.umn.edu/~kumar/dmbook/ch8.pdf see table 8.2 page 501). Yes I could implement easily k-means but I will lose lot of benefits from sklearn frameworks such as the ability to compare easily several unsupervised algorithms. I was simply expected the distance function to be configurable as it is with many other sklearn functions.

You can implement it and inherit from BaseEstimator (and optionally cluster mixin) There is no magic to making a sklearn estimator, you just have to define "fit" and "predict".

Actually there are not many place in sklearn where you can pass callables to customize an algorithm. The thing is that you would need to provide a pairwise distance measure and a function to compute the center and these should be compatible. If they are not, the algorithm might not stop (afaik). So does the algorithm check for endless loops? Does it check whether computing the center
does the right thing? Or does it check for infinite loops?

On the other hand, do you know why metrics.cluster.unsupervised.silhouette_score required the labels? I understand that we can compute the supervised version of the silhouette score but was looking for the unsupervised version. Even the help doesn't mention anywhere the labels.

The labels here are the cluster assignments you want to evaluate. Just passing X is no good, is it ;)

Cheers,
Andy
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