> A combiner is definitely the next step. It is definitely not. Why do you need to sort???
> One question, is there already a writable for tuples of e.g. int and Vector, > or should I just write one from scratch? >From scratch. Or, you can save n as first element in the vector, why not. Your front end code would know how to re-shuffle that. But if not that, then custom writable. TupleWritable saves the class with the value. That's exactly why they invented writables and not using java serialization: you must not save type with each value. -d On Sun, Dec 11, 2011 at 8:14 PM, Raphael Cendrillon (Commented) (JIRA) <j...@apache.org> wrote: > > [ > https://issues.apache.org/jira/browse/MAHOUT-923?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13167341#comment-13167341 > ] > > Raphael Cendrillon commented on MAHOUT-923: > ------------------------------------------- > > Thanks Lance. A combiner is definitely the next step. One question, is there > already a writable for tuples of e.g. int and Vector, or should I just write > one from scratch? I know there is TupleWritable, but from what I've read > online it's better to avoid that unless you're doing a multiple input join. > > Regarding the class for the output vector, are you saying that instead of > inhereting the class from the rows of the DistributedRowMatrix you'd rather > be able to specify this manually? > > > >> Row mean job for PCA >> -------------------- >> >> Key: MAHOUT-923 >> URL: https://issues.apache.org/jira/browse/MAHOUT-923 >> Project: Mahout >> Issue Type: Improvement >> Components: Math >> Affects Versions: 0.6 >> Reporter: Raphael Cendrillon >> Assignee: Raphael Cendrillon >> Fix For: Backlog >> >> Attachments: MAHOUT-923.patch >> >> >> Add map reduce job for calculating mean row (column-wise mean) of a >> Distributed Row Matrix for use in PCA. > > -- > This message is automatically generated by JIRA. > If you think it was sent incorrectly, please contact your JIRA > administrators: > https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa > For more information on JIRA, see: http://www.atlassian.com/software/jira > >
