Colt uses a foreachNonZero method that accepts what is essentially a closure. This works reasonably well. A real iterator might be better, but I can't say, having used only the Colt method.
I can see that having a nonZeroIndexIterator might be a very nice way to do this. Ultimately, one approach or the other might play better with the JIT and inlining, but I definitely wouldn't worry about that yet. On 4/9/08 9:21 AM, "Isabel Drost (JIRA)" <[EMAIL PROTECTED]> wrote: > > [ > https://issues.apache.org/jira/browse/MAHOUT-20?page=com.atlassian.jira.plugin > .system.issuetabpanels:comment-tabpanel&focusedCommentId=12587253#action_12587 > 253 ] > > Isabel Drost commented on MAHOUT-20: > ------------------------------------ > > > 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. > > > >> Migrate Canopy and KMeans Implementations to Vectors >> ---------------------------------------------------- >> >> Key: MAHOUT-20 >> URL: https://issues.apache.org/jira/browse/MAHOUT-20 >> Project: Mahout >> Issue Type: Task >> Components: Clustering >> Affects Versions: 0.1 >> Reporter: Jeff Eastman >> Assignee: Isabel Drost >> Attachments: vectorClustering.txt >> >> >> Canopy and KMeans clustering implementations use Float[] representations >> instead of the new Vector package. They need to be migrated and the Vector >> package may need some enhancement to support the notion of payloads. This >> would be a good project for somebody new to the project who wants to get >> involved. If somebody wants to implement this, just assign the issue to >> yourself and I will hold off doing it myself.
