I guess, I will correct the first point Jeff mentioned on list.
> One possible alternative might be to add a sort of iterator mechanism in the Vector interface. That would
> only visit non-null elements.
+1 to that. Maybe we could add that functionality after the patch is comitted, enhance the vector implementation after that? There were a few other points that Jeff mentioned. I would rather like to keep this patch focussed on the k-Means and Canopy classes and rather not touch the matrix stuff in it.
The alternative would be to wait with the patch until the proposed functionality is available in the matrix stuff.