I Would recommend not worrying about having a special symmetric matrix for now. It won't make a huge difference and it will be a pain to convert the one that ssvd uses.
The diagonal matrix could make a much bigger difference. Sent from my iPhone On Jan 14, 2012, at 15:06, Lance Norskog <[email protected]> wrote: > There is a packed symmetric matrix impl in the Stochastic SVD stuff, > but it is hard-coded to a packed implementation. > org.apache.mahout.math.hadoop.stochasticsvd.UpperTriangular - mahout/math > > You could recode this to use the Vector class for storage. Be sure to > run all of the Matrix unit tests if you do this; Matrix has a lot of > things that can go wrong. > > On Sat, Jan 14, 2012 at 2:03 AM, Tamas Jambor <[email protected]> wrote: >> thanks, ideally I would need both symmetric and diagonal. >> >> On Sat, Jan 14, 2012 at 8:26 AM, Sebastian Schelter <[email protected]> wrote: >> >>> I think Tamas referred to matrices that are symmetric (only the upper >>> triangular half would need to be stored) not diagonal matrices. >>> >>> >>> On 14.01.2012 05:25, Lance Norskog wrote: >>>> org.apache.mahout.math.DiagonalMatrix >>>> >>>> It even supports sparse values in the diagonal! >>>> >>>> On Fri, Jan 13, 2012 at 9:00 AM, Tamas Jambor (Commented) (JIRA) >>>> <[email protected]> wrote: >>>>> >>>>> [ >>> https://issues.apache.org/jira/browse/MAHOUT-737?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13185670#comment-13185670] >>>>> >>>>> Tamas Jambor commented on MAHOUT-737: >>>>> ------------------------------------- >>>>> >>>>> I think so. When will you be releasing 0.6? I am planning to do a bit >>> more extensive testing in the next 2-3 weeks. >>>>> >>>>>> Implicit Alternating Least Squares SVD >>>>>> -------------------------------------- >>>>>> >>>>>> Key: MAHOUT-737 >>>>>> URL: https://issues.apache.org/jira/browse/MAHOUT-737 >>>>>> Project: Mahout >>>>>> Issue Type: New Feature >>>>>> Components: Collaborative Filtering >>>>>> Affects Versions: 0.6 >>>>>> Reporter: Tamas Jambor >>>>>> Assignee: Sebastian Schelter >>>>>> Attachments: MAHOUT-737-2.patch, MAHOUT-737.patch, >>> MAHOUT-737.patch, MAHOUT-737.patch, MAHOUT-737.patch >>>>>> >>>>>> >>>>>> I am sharing this Java implementation of mine that is based on the >>> paper - Collaborative Filtering with Implicit Datasets. The implementation >>> is multi-treading and can be easily extended to use it on Hadoop. In fact >>> this approach would possibly work with non-implicit datasets, but further >>> testing is needed. The algorithm is tried and tested on an implicit >>> TV-viewing dataset, and the performance was pretty good (details to follow). >>>>> >>>>> -- >>>>> 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 >>>>> >>>>> >>>> >>>> >>>> >>> >>> > > > > -- > Lance Norskog > [email protected]
